first add files

lib/sqlalchemy/__init__.py

@@ -0,0 +1,158 @@
+# sqlalchemy/__init__.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from . import util as _util
+from .engine import create_engine
+from .engine import create_mock_engine
+from .engine import engine_from_config
+from .inspection import inspect
+from .schema import BLANK_SCHEMA
+from .schema import CheckConstraint
+from .schema import Column
+from .schema import ColumnDefault
+from .schema import Computed
+from .schema import Constraint
+from .schema import DDL
+from .schema import DefaultClause
+from .schema import FetchedValue
+from .schema import ForeignKey
+from .schema import ForeignKeyConstraint
+from .schema import Identity
+from .schema import Index
+from .schema import MetaData
+from .schema import PrimaryKeyConstraint
+from .schema import Sequence
+from .schema import Table
+from .schema import ThreadLocalMetaData
+from .schema import UniqueConstraint
+from .sql import alias
+from .sql import all_
+from .sql import and_
+from .sql import any_
+from .sql import asc
+from .sql import between
+from .sql import bindparam
+from .sql import case
+from .sql import cast
+from .sql import collate
+from .sql import column
+from .sql import delete
+from .sql import desc
+from .sql import distinct
+from .sql import except_
+from .sql import except_all
+from .sql import exists
+from .sql import extract
+from .sql import false
+from .sql import func
+from .sql import funcfilter
+from .sql import insert
+from .sql import intersect
+from .sql import intersect_all
+from .sql import join
+from .sql import LABEL_STYLE_DEFAULT
+from .sql import LABEL_STYLE_DISAMBIGUATE_ONLY
+from .sql import LABEL_STYLE_NONE
+from .sql import LABEL_STYLE_TABLENAME_PLUS_COL
+from .sql import lambda_stmt
+from .sql import lateral
+from .sql import literal
+from .sql import literal_column
+from .sql import modifier
+from .sql import not_
+from .sql import null
+from .sql import nulls_first
+from .sql import nulls_last
+from .sql import nullsfirst
+from .sql import nullslast
+from .sql import or_
+from .sql import outerjoin
+from .sql import outparam
+from .sql import over
+from .sql import select
+from .sql import subquery
+from .sql import table
+from .sql import tablesample
+from .sql import text
+from .sql import true
+from .sql import tuple_
+from .sql import type_coerce
+from .sql import union
+from .sql import union_all
+from .sql import update
+from .sql import values
+from .sql import within_group
+from .types import ARRAY
+from .types import BIGINT
+from .types import BigInteger
+from .types import BINARY
+from .types import BLOB
+from .types import BOOLEAN
+from .types import Boolean
+from .types import CHAR
+from .types import CLOB
+from .types import DATE
+from .types import Date
+from .types import DATETIME
+from .types import DateTime
+from .types import DECIMAL
+from .types import Enum
+from .types import FLOAT
+from .types import Float
+from .types import INT
+from .types import INTEGER
+from .types import Integer
+from .types import Interval
+from .types import JSON
+from .types import LargeBinary
+from .types import NCHAR
+from .types import NUMERIC
+from .types import Numeric
+from .types import NVARCHAR
+from .types import PickleType
+from .types import REAL
+from .types import SMALLINT
+from .types import SmallInteger
+from .types import String
+from .types import TEXT
+from .types import Text
+from .types import TIME
+from .types import Time
+from .types import TIMESTAMP
+from .types import TupleType
+from .types import TypeDecorator
+from .types import Unicode
+from .types import UnicodeText
+from .types import VARBINARY
+from .types import VARCHAR
+
+
+__version__ = "1.4.40"
+
+
+def __go(lcls):
+    global __all__
+
+    from . import events
+    from . import util as _sa_util
+
+    import inspect as _inspect
+
+    __all__ = sorted(
+        name
+        for name, obj in lcls.items()
+        if not (name.startswith("_") or _inspect.ismodule(obj))
+    )
+
+    _sa_util.preloaded.import_prefix("sqlalchemy")
+
+    from . import exc
+
+    exc._version_token = "".join(__version__.split(".")[0:2])
+
+
+__go(locals())

lib/sqlalchemy/connectors/__init__.py

@@ -0,0 +1,10 @@
+# connectors/__init__.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+
+class Connector(object):
+    pass

lib/sqlalchemy/connectors/mxodbc.py

@@ -0,0 +1,166 @@
+# connectors/mxodbc.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""
+Provide a SQLALchemy connector for the eGenix mxODBC commercial
+Python adapter for ODBC. This is not a free product, but eGenix
+provides SQLAlchemy with a license for use in continuous integration
+testing.
+
+This has been tested for use with mxODBC 3.1.2 on SQL Server 2005
+and 2008, using the SQL Server Native driver. However, it is
+possible for this to be used on other database platforms.
+
+For more info on mxODBC, see https://www.egenix.com/
+
+.. deprecated:: 1.4 The mxODBC DBAPI is deprecated and will be removed
+   in a future version. Please use one of the supported DBAPIs to
+   connect to mssql.
+
+"""
+
+import re
+import sys
+import warnings
+
+from . import Connector
+from ..util import warn_deprecated
+
+
+class MxODBCConnector(Connector):
+    driver = "mxodbc"
+
+    supports_sane_multi_rowcount = False
+    supports_unicode_statements = True
+    supports_unicode_binds = True
+
+    supports_native_decimal = True
+
+    @classmethod
+    def dbapi(cls):
+        # this classmethod will normally be replaced by an instance
+        # attribute of the same name, so this is normally only called once.
+        cls._load_mx_exceptions()
+        platform = sys.platform
+        if platform == "win32":
+            from mx.ODBC import Windows as Module
+        # this can be the string "linux2", and possibly others
+        elif "linux" in platform:
+            from mx.ODBC import unixODBC as Module
+        elif platform == "darwin":
+            from mx.ODBC import iODBC as Module
+        else:
+            raise ImportError("Unrecognized platform for mxODBC import")
+
+        warn_deprecated(
+            "The mxODBC DBAPI is deprecated and will be removed"
+            "in a future version. Please use one of the supported DBAPIs to"
+            "connect to mssql.",
+            version="1.4",
+        )
+        return Module
+
+    @classmethod
+    def _load_mx_exceptions(cls):
+        """Import mxODBC exception classes into the module namespace,
+        as if they had been imported normally. This is done here
+        to avoid requiring all SQLAlchemy users to install mxODBC.
+        """
+        global InterfaceError, ProgrammingError
+        from mx.ODBC import InterfaceError
+        from mx.ODBC import ProgrammingError
+
+    def on_connect(self):
+        def connect(conn):
+            conn.stringformat = self.dbapi.MIXED_STRINGFORMAT
+            conn.datetimeformat = self.dbapi.PYDATETIME_DATETIMEFORMAT
+            conn.decimalformat = self.dbapi.DECIMAL_DECIMALFORMAT
+            conn.errorhandler = self._error_handler()
+
+        return connect
+
+    def _error_handler(self):
+        """Return a handler that adjusts mxODBC's raised Warnings to
+        emit Python standard warnings.
+        """
+        from mx.ODBC.Error import Warning as MxOdbcWarning
+
+        def error_handler(connection, cursor, errorclass, errorvalue):
+            if issubclass(errorclass, MxOdbcWarning):
+                errorclass.__bases__ = (Warning,)
+                warnings.warn(
+                    message=str(errorvalue), category=errorclass, stacklevel=2
+                )
+            else:
+                raise errorclass(errorvalue)
+
+        return error_handler
+
+    def create_connect_args(self, url):
+        r"""Return a tuple of \*args, \**kwargs for creating a connection.
+
+        The mxODBC 3.x connection constructor looks like this:
+
+            connect(dsn, user='', password='',
+                    clear_auto_commit=1, errorhandler=None)
+
+        This method translates the values in the provided URI
+        into args and kwargs needed to instantiate an mxODBC Connection.
+
+        The arg 'errorhandler' is not used by SQLAlchemy and will
+        not be populated.
+
+        """
+        opts = url.translate_connect_args(username="user")
+        opts.update(url.query)
+        args = opts.pop("host")
+        opts.pop("port", None)
+        opts.pop("database", None)
+        return (args,), opts
+
+    def is_disconnect(self, e, connection, cursor):
+        # TODO: eGenix recommends checking connection.closed here
+        # Does that detect dropped connections ?
+        if isinstance(e, self.dbapi.ProgrammingError):
+            return "connection already closed" in str(e)
+        elif isinstance(e, self.dbapi.Error):
+            return "[08S01]" in str(e)
+        else:
+            return False
+
+    def _get_server_version_info(self, connection):
+        # eGenix suggests using conn.dbms_version instead
+        # of what we're doing here
+        dbapi_con = connection.connection
+        version = []
+        r = re.compile(r"[.\-]")
+        # 18 == pyodbc.SQL_DBMS_VER
+        for n in r.split(dbapi_con.getinfo(18)[1]):
+            try:
+                version.append(int(n))
+            except ValueError:
+                version.append(n)
+        return tuple(version)
+
+    def _get_direct(self, context):
+        if context:
+            native_odbc_execute = context.execution_options.get(
+                "native_odbc_execute", "auto"
+            )
+            # default to direct=True in all cases, is more generally
+            # compatible especially with SQL Server
+            return False if native_odbc_execute is True else True
+        else:
+            return True
+
+    def do_executemany(self, cursor, statement, parameters, context=None):
+        cursor.executemany(
+            statement, parameters, direct=self._get_direct(context)
+        )
+
+    def do_execute(self, cursor, statement, parameters, context=None):
+        cursor.execute(statement, parameters, direct=self._get_direct(context))

lib/sqlalchemy/connectors/pyodbc.py

@@ -0,0 +1,193 @@
+# connectors/pyodbc.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+import re
+
+from . import Connector
+from .. import util
+
+
+class PyODBCConnector(Connector):
+    driver = "pyodbc"
+
+    # this is no longer False for pyodbc in general
+    supports_sane_rowcount_returning = True
+    supports_sane_multi_rowcount = False
+
+    supports_unicode_statements = True
+    supports_unicode_binds = True
+
+    supports_native_decimal = True
+    default_paramstyle = "named"
+
+    use_setinputsizes = False
+
+    # for non-DSN connections, this *may* be used to
+    # hold the desired driver name
+    pyodbc_driver_name = None
+
+    def __init__(
+        self, supports_unicode_binds=None, use_setinputsizes=False, **kw
+    ):
+        super(PyODBCConnector, self).__init__(**kw)
+        if supports_unicode_binds is not None:
+            self.supports_unicode_binds = supports_unicode_binds
+        self.use_setinputsizes = use_setinputsizes
+
+    @classmethod
+    def dbapi(cls):
+        return __import__("pyodbc")
+
+    def create_connect_args(self, url):
+        opts = url.translate_connect_args(username="user")
+        opts.update(url.query)
+
+        keys = opts
+
+        query = url.query
+
+        connect_args = {}
+        for param in ("ansi", "unicode_results", "autocommit"):
+            if param in keys:
+                connect_args[param] = util.asbool(keys.pop(param))
+
+        if "odbc_connect" in keys:
+            connectors = [util.unquote_plus(keys.pop("odbc_connect"))]
+        else:
+
+            def check_quote(token):
+                if ";" in str(token) or str(token).startswith("{"):
+                    token = "{%s}" % token.replace("}", "}}")
+                return token
+
+            keys = dict((k, check_quote(v)) for k, v in keys.items())
+
+            dsn_connection = "dsn" in keys or (
+                "host" in keys and "database" not in keys
+            )
+            if dsn_connection:
+                connectors = [
+                    "dsn=%s" % (keys.pop("host", "") or keys.pop("dsn", ""))
+                ]
+            else:
+                port = ""
+                if "port" in keys and "port" not in query:
+                    port = ",%d" % int(keys.pop("port"))
+
+                connectors = []
+                driver = keys.pop("driver", self.pyodbc_driver_name)
+                if driver is None and keys:
+                    # note if keys is empty, this is a totally blank URL
+                    util.warn(
+                        "No driver name specified; "
+                        "this is expected by PyODBC when using "
+                        "DSN-less connections"
+                    )
+                else:
+                    connectors.append("DRIVER={%s}" % driver)
+
+                connectors.extend(
+                    [
+                        "Server=%s%s" % (keys.pop("host", ""), port),
+                        "Database=%s" % keys.pop("database", ""),
+                    ]
+                )
+
+            user = keys.pop("user", None)
+            if user:
+                connectors.append("UID=%s" % user)
+                pwd = keys.pop("password", "")
+                if pwd:
+                    connectors.append("PWD=%s" % pwd)
+            else:
+                authentication = keys.pop("authentication", None)
+                if authentication:
+                    connectors.append("Authentication=%s" % authentication)
+                else:
+                    connectors.append("Trusted_Connection=Yes")
+
+            # if set to 'Yes', the ODBC layer will try to automagically
+            # convert textual data from your database encoding to your
+            # client encoding.  This should obviously be set to 'No' if
+            # you query a cp1253 encoded database from a latin1 client...
+            if "odbc_autotranslate" in keys:
+                connectors.append(
+                    "AutoTranslate=%s" % keys.pop("odbc_autotranslate")
+                )
+
+            connectors.extend(["%s=%s" % (k, v) for k, v in keys.items()])
+
+        return [[";".join(connectors)], connect_args]
+
+    def is_disconnect(self, e, connection, cursor):
+        if isinstance(e, self.dbapi.ProgrammingError):
+            return "The cursor's connection has been closed." in str(
+                e
+            ) or "Attempt to use a closed connection." in str(e)
+        else:
+            return False
+
+    def _dbapi_version(self):
+        if not self.dbapi:
+            return ()
+        return self._parse_dbapi_version(self.dbapi.version)
+
+    def _parse_dbapi_version(self, vers):
+        m = re.match(r"(?:py.*-)?([\d\.]+)(?:-(\w+))?", vers)
+        if not m:
+            return ()
+        vers = tuple([int(x) for x in m.group(1).split(".")])
+        if m.group(2):
+            vers += (m.group(2),)
+        return vers
+
+    def _get_server_version_info(self, connection, allow_chars=True):
+        # NOTE: this function is not reliable, particularly when
+        # freetds is in use.   Implement database-specific server version
+        # queries.
+        dbapi_con = connection.connection
+        version = []
+        r = re.compile(r"[.\-]")
+        for n in r.split(dbapi_con.getinfo(self.dbapi.SQL_DBMS_VER)):
+            try:
+                version.append(int(n))
+            except ValueError:
+                if allow_chars:
+                    version.append(n)
+        return tuple(version)
+
+    def do_set_input_sizes(self, cursor, list_of_tuples, context):
+        # the rules for these types seems a little strange, as you can pass
+        # non-tuples as well as tuples, however it seems to assume "0"
+        # for the subsequent values if you don't pass a tuple which fails
+        # for types such as pyodbc.SQL_WLONGVARCHAR, which is the datatype
+        # that ticket #5649 is targeting.
+
+        # NOTE: as of #6058, this won't be called if the use_setinputsizes flag
+        # is False, or if no types were specified in list_of_tuples
+
+        cursor.setinputsizes(
+            [
+                (dbtype, None, None)
+                if not isinstance(dbtype, tuple)
+                else dbtype
+                for key, dbtype, sqltype in list_of_tuples
+            ]
+        )
+
+    def set_isolation_level(self, connection, level):
+        # adjust for ConnectionFairy being present
+        # allows attribute set e.g. "connection.autocommit = True"
+        # to work properly
+        if hasattr(connection, "dbapi_connection"):
+            connection = connection.dbapi_connection
+
+        if level == "AUTOCOMMIT":
+            connection.autocommit = True
+        else:
+            connection.autocommit = False
+            super(PyODBCConnector, self).set_isolation_level(connection, level)

lib/sqlalchemy/databases/__init__.py

@@ -0,0 +1,38 @@
+# databases/__init__.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""Include imports from the sqlalchemy.dialects package for backwards
+compatibility with pre 0.6 versions.
+
+"""
+from ..dialects.firebird import base as firebird
+from ..dialects.mssql import base as mssql
+from ..dialects.mysql import base as mysql
+from ..dialects.oracle import base as oracle
+from ..dialects.postgresql import base as postgresql
+from ..dialects.sqlite import base as sqlite
+from ..dialects.sybase import base as sybase
+from ..util import warn_deprecated_20
+
+postgres = postgresql
+
+
+__all__ = (
+    "firebird",
+    "mssql",
+    "mysql",
+    "postgresql",
+    "sqlite",
+    "oracle",
+    "sybase",
+)
+
+
+warn_deprecated_20(
+    "The `database` package is deprecated and will be removed in v2.0 "
+    "of sqlalchemy. Use the `dialects` package instead."
+)

lib/sqlalchemy/dialects/__init__.py

@@ -0,0 +1,72 @@
+# dialects/__init__.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+__all__ = (
+    "firebird",
+    "mssql",
+    "mysql",
+    "oracle",
+    "postgresql",
+    "sqlite",
+    "sybase",
+)
+
+
+from .. import util
+
+
+def _auto_fn(name):
+    """default dialect importer.
+
+    plugs into the :class:`.PluginLoader`
+    as a first-hit system.
+
+    """
+    if "." in name:
+        dialect, driver = name.split(".")
+    else:
+        dialect = name
+        driver = "base"
+
+    try:
+        if dialect == "firebird":
+            try:
+                module = __import__("sqlalchemy_firebird")
+            except ImportError:
+                module = __import__("sqlalchemy.dialects.firebird").dialects
+                module = getattr(module, dialect)
+        elif dialect == "sybase":
+            try:
+                module = __import__("sqlalchemy_sybase")
+            except ImportError:
+                module = __import__("sqlalchemy.dialects.sybase").dialects
+                module = getattr(module, dialect)
+        elif dialect == "mariadb":
+            # it's "OK" for us to hardcode here since _auto_fn is already
+            # hardcoded.   if mysql / mariadb etc were third party dialects
+            # they would just publish all the entrypoints, which would actually
+            # look much nicer.
+            module = __import__(
+                "sqlalchemy.dialects.mysql.mariadb"
+            ).dialects.mysql.mariadb
+            return module.loader(driver)
+        else:
+            module = __import__("sqlalchemy.dialects.%s" % (dialect,)).dialects
+            module = getattr(module, dialect)
+    except ImportError:
+        return None
+
+    if hasattr(module, driver):
+        module = getattr(module, driver)
+        return lambda: module.dialect
+    else:
+        return None
+
+
+registry = util.PluginLoader("sqlalchemy.dialects", auto_fn=_auto_fn)
+
+plugins = util.PluginLoader("sqlalchemy.plugins")

lib/sqlalchemy/dialects/firebird/__init__.py

@@ -0,0 +1,41 @@
+# firebird/__init__.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from sqlalchemy.dialects.firebird.base import BIGINT
+from sqlalchemy.dialects.firebird.base import BLOB
+from sqlalchemy.dialects.firebird.base import CHAR
+from sqlalchemy.dialects.firebird.base import DATE
+from sqlalchemy.dialects.firebird.base import FLOAT
+from sqlalchemy.dialects.firebird.base import NUMERIC
+from sqlalchemy.dialects.firebird.base import SMALLINT
+from sqlalchemy.dialects.firebird.base import TEXT
+from sqlalchemy.dialects.firebird.base import TIME
+from sqlalchemy.dialects.firebird.base import TIMESTAMP
+from sqlalchemy.dialects.firebird.base import VARCHAR
+from . import base  # noqa
+from . import fdb  # noqa
+from . import kinterbasdb  # noqa
+
+
+base.dialect = dialect = fdb.dialect
+
+__all__ = (
+    "SMALLINT",
+    "BIGINT",
+    "FLOAT",
+    "FLOAT",
+    "DATE",
+    "TIME",
+    "TEXT",
+    "NUMERIC",
+    "FLOAT",
+    "TIMESTAMP",
+    "VARCHAR",
+    "CHAR",
+    "BLOB",
+    "dialect",
+)

lib/sqlalchemy/dialects/firebird/base.py

@@ -0,0 +1,989 @@
+# firebird/base.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+r"""
+
+.. dialect:: firebird
+    :name: Firebird
+
+.. note::
+
+    The Firebird dialect within SQLAlchemy **is not currently supported**.
+    It is not tested within continuous integration and is likely to have
+    many issues and caveats not currently handled. Consider using the
+    `external dialect <https://github.com/pauldex/sqlalchemy-firebird>`_
+    instead.
+
+.. deprecated:: 1.4 The internal Firebird dialect is deprecated and will be
+   removed in a future version. Use the external dialect.
+
+Firebird Dialects
+-----------------
+
+Firebird offers two distinct dialects_ (not to be confused with a
+SQLAlchemy ``Dialect``):
+
+dialect 1
+  This is the old syntax and behaviour, inherited from Interbase pre-6.0.
+
+dialect 3
+  This is the newer and supported syntax, introduced in Interbase 6.0.
+
+The SQLAlchemy Firebird dialect detects these versions and
+adjusts its representation of SQL accordingly.  However,
+support for dialect 1 is not well tested and probably has
+incompatibilities.
+
+Locking Behavior
+----------------
+
+Firebird locks tables aggressively.  For this reason, a DROP TABLE may
+hang until other transactions are released.  SQLAlchemy does its best
+to release transactions as quickly as possible.  The most common cause
+of hanging transactions is a non-fully consumed result set, i.e.::
+
+    result = engine.execute(text("select * from table"))
+    row = result.fetchone()
+    return
+
+Where above, the ``CursorResult`` has not been fully consumed.  The
+connection will be returned to the pool and the transactional state
+rolled back once the Python garbage collector reclaims the objects
+which hold onto the connection, which often occurs asynchronously.
+The above use case can be alleviated by calling ``first()`` on the
+``CursorResult`` which will fetch the first row and immediately close
+all remaining cursor/connection resources.
+
+RETURNING support
+-----------------
+
+Firebird 2.0 supports returning a result set from inserts, and 2.1
+extends that to deletes and updates. This is generically exposed by
+the SQLAlchemy ``returning()`` method, such as::
+
+    # INSERT..RETURNING
+    result = table.insert().returning(table.c.col1, table.c.col2).\
+                   values(name='foo')
+    print(result.fetchall())
+
+    # UPDATE..RETURNING
+    raises = empl.update().returning(empl.c.id, empl.c.salary).\
+                  where(empl.c.sales>100).\
+                  values(dict(salary=empl.c.salary * 1.1))
+    print(raises.fetchall())
+
+
+.. _dialects: https://mc-computing.com/Databases/Firebird/SQL_Dialect.html
+"""
+
+import datetime
+
+from sqlalchemy import exc
+from sqlalchemy import sql
+from sqlalchemy import types as sqltypes
+from sqlalchemy import util
+from sqlalchemy.engine import default
+from sqlalchemy.engine import reflection
+from sqlalchemy.sql import compiler
+from sqlalchemy.sql import expression
+from sqlalchemy.types import BIGINT
+from sqlalchemy.types import BLOB
+from sqlalchemy.types import DATE
+from sqlalchemy.types import FLOAT
+from sqlalchemy.types import INTEGER
+from sqlalchemy.types import Integer
+from sqlalchemy.types import NUMERIC
+from sqlalchemy.types import SMALLINT
+from sqlalchemy.types import TEXT
+from sqlalchemy.types import TIME
+from sqlalchemy.types import TIMESTAMP
+
+
+RESERVED_WORDS = set(
+    [
+        "active",
+        "add",
+        "admin",
+        "after",
+        "all",
+        "alter",
+        "and",
+        "any",
+        "as",
+        "asc",
+        "ascending",
+        "at",
+        "auto",
+        "avg",
+        "before",
+        "begin",
+        "between",
+        "bigint",
+        "bit_length",
+        "blob",
+        "both",
+        "by",
+        "case",
+        "cast",
+        "char",
+        "character",
+        "character_length",
+        "char_length",
+        "check",
+        "close",
+        "collate",
+        "column",
+        "commit",
+        "committed",
+        "computed",
+        "conditional",
+        "connect",
+        "constraint",
+        "containing",
+        "count",
+        "create",
+        "cross",
+        "cstring",
+        "current",
+        "current_connection",
+        "current_date",
+        "current_role",
+        "current_time",
+        "current_timestamp",
+        "current_transaction",
+        "current_user",
+        "cursor",
+        "database",
+        "date",
+        "day",
+        "dec",
+        "decimal",
+        "declare",
+        "default",
+        "delete",
+        "desc",
+        "descending",
+        "disconnect",
+        "distinct",
+        "do",
+        "domain",
+        "double",
+        "drop",
+        "else",
+        "end",
+        "entry_point",
+        "escape",
+        "exception",
+        "execute",
+        "exists",
+        "exit",
+        "external",
+        "extract",
+        "fetch",
+        "file",
+        "filter",
+        "float",
+        "for",
+        "foreign",
+        "from",
+        "full",
+        "function",
+        "gdscode",
+        "generator",
+        "gen_id",
+        "global",
+        "grant",
+        "group",
+        "having",
+        "hour",
+        "if",
+        "in",
+        "inactive",
+        "index",
+        "inner",
+        "input_type",
+        "insensitive",
+        "insert",
+        "int",
+        "integer",
+        "into",
+        "is",
+        "isolation",
+        "join",
+        "key",
+        "leading",
+        "left",
+        "length",
+        "level",
+        "like",
+        "long",
+        "lower",
+        "manual",
+        "max",
+        "maximum_segment",
+        "merge",
+        "min",
+        "minute",
+        "module_name",
+        "month",
+        "names",
+        "national",
+        "natural",
+        "nchar",
+        "no",
+        "not",
+        "null",
+        "numeric",
+        "octet_length",
+        "of",
+        "on",
+        "only",
+        "open",
+        "option",
+        "or",
+        "order",
+        "outer",
+        "output_type",
+        "overflow",
+        "page",
+        "pages",
+        "page_size",
+        "parameter",
+        "password",
+        "plan",
+        "position",
+        "post_event",
+        "precision",
+        "primary",
+        "privileges",
+        "procedure",
+        "protected",
+        "rdb$db_key",
+        "read",
+        "real",
+        "record_version",
+        "recreate",
+        "recursive",
+        "references",
+        "release",
+        "reserv",
+        "reserving",
+        "retain",
+        "returning_values",
+        "returns",
+        "revoke",
+        "right",
+        "rollback",
+        "rows",
+        "row_count",
+        "savepoint",
+        "schema",
+        "second",
+        "segment",
+        "select",
+        "sensitive",
+        "set",
+        "shadow",
+        "shared",
+        "singular",
+        "size",
+        "smallint",
+        "snapshot",
+        "some",
+        "sort",
+        "sqlcode",
+        "stability",
+        "start",
+        "starting",
+        "starts",
+        "statistics",
+        "sub_type",
+        "sum",
+        "suspend",
+        "table",
+        "then",
+        "time",
+        "timestamp",
+        "to",
+        "trailing",
+        "transaction",
+        "trigger",
+        "trim",
+        "uncommitted",
+        "union",
+        "unique",
+        "update",
+        "upper",
+        "user",
+        "using",
+        "value",
+        "values",
+        "varchar",
+        "variable",
+        "varying",
+        "view",
+        "wait",
+        "when",
+        "where",
+        "while",
+        "with",
+        "work",
+        "write",
+        "year",
+    ]
+)
+
+
+class _StringType(sqltypes.String):
+    """Base for Firebird string types."""
+
+    def __init__(self, charset=None, **kw):
+        self.charset = charset
+        super(_StringType, self).__init__(**kw)
+
+
+class VARCHAR(_StringType, sqltypes.VARCHAR):
+    """Firebird VARCHAR type"""
+
+    __visit_name__ = "VARCHAR"
+
+    def __init__(self, length=None, **kwargs):
+        super(VARCHAR, self).__init__(length=length, **kwargs)
+
+
+class CHAR(_StringType, sqltypes.CHAR):
+    """Firebird CHAR type"""
+
+    __visit_name__ = "CHAR"
+
+    def __init__(self, length=None, **kwargs):
+        super(CHAR, self).__init__(length=length, **kwargs)
+
+
+class _FBDateTime(sqltypes.DateTime):
+    def bind_processor(self, dialect):
+        def process(value):
+            if type(value) == datetime.date:
+                return datetime.datetime(value.year, value.month, value.day)
+            else:
+                return value
+
+        return process
+
+
+colspecs = {sqltypes.DateTime: _FBDateTime}
+
+ischema_names = {
+    "SHORT": SMALLINT,
+    "LONG": INTEGER,
+    "QUAD": FLOAT,
+    "FLOAT": FLOAT,
+    "DATE": DATE,
+    "TIME": TIME,
+    "TEXT": TEXT,
+    "INT64": BIGINT,
+    "DOUBLE": FLOAT,
+    "TIMESTAMP": TIMESTAMP,
+    "VARYING": VARCHAR,
+    "CSTRING": CHAR,
+    "BLOB": BLOB,
+}
+
+
+# TODO: date conversion types (should be implemented as _FBDateTime,
+# _FBDate, etc. as bind/result functionality is required)
+
+
+class FBTypeCompiler(compiler.GenericTypeCompiler):
+    def visit_boolean(self, type_, **kw):
+        return self.visit_SMALLINT(type_, **kw)
+
+    def visit_datetime(self, type_, **kw):
+        return self.visit_TIMESTAMP(type_, **kw)
+
+    def visit_TEXT(self, type_, **kw):
+        return "BLOB SUB_TYPE 1"
+
+    def visit_BLOB(self, type_, **kw):
+        return "BLOB SUB_TYPE 0"
+
+    def _extend_string(self, type_, basic):
+        charset = getattr(type_, "charset", None)
+        if charset is None:
+            return basic
+        else:
+            return "%s CHARACTER SET %s" % (basic, charset)
+
+    def visit_CHAR(self, type_, **kw):
+        basic = super(FBTypeCompiler, self).visit_CHAR(type_, **kw)
+        return self._extend_string(type_, basic)
+
+    def visit_VARCHAR(self, type_, **kw):
+        if not type_.length:
+            raise exc.CompileError(
+                "VARCHAR requires a length on dialect %s" % self.dialect.name
+            )
+        basic = super(FBTypeCompiler, self).visit_VARCHAR(type_, **kw)
+        return self._extend_string(type_, basic)
+
+
+class FBCompiler(sql.compiler.SQLCompiler):
+    """Firebird specific idiosyncrasies"""
+
+    ansi_bind_rules = True
+
+    # def visit_contains_op_binary(self, binary, operator, **kw):
+    # cant use CONTAINING b.c. it's case insensitive.
+
+    # def visit_not_contains_op_binary(self, binary, operator, **kw):
+    # cant use NOT CONTAINING b.c. it's case insensitive.
+
+    def visit_now_func(self, fn, **kw):
+        return "CURRENT_TIMESTAMP"
+
+    def visit_startswith_op_binary(self, binary, operator, **kw):
+        return "%s STARTING WITH %s" % (
+            binary.left._compiler_dispatch(self, **kw),
+            binary.right._compiler_dispatch(self, **kw),
+        )
+
+    def visit_not_startswith_op_binary(self, binary, operator, **kw):
+        return "%s NOT STARTING WITH %s" % (
+            binary.left._compiler_dispatch(self, **kw),
+            binary.right._compiler_dispatch(self, **kw),
+        )
+
+    def visit_mod_binary(self, binary, operator, **kw):
+        return "mod(%s, %s)" % (
+            self.process(binary.left, **kw),
+            self.process(binary.right, **kw),
+        )
+
+    def visit_alias(self, alias, asfrom=False, **kwargs):
+        if self.dialect._version_two:
+            return super(FBCompiler, self).visit_alias(
+                alias, asfrom=asfrom, **kwargs
+            )
+        else:
+            # Override to not use the AS keyword which FB 1.5 does not like
+            if asfrom:
+                alias_name = (
+                    isinstance(alias.name, expression._truncated_label)
+                    and self._truncated_identifier("alias", alias.name)
+                    or alias.name
+                )
+
+                return (
+                    self.process(alias.element, asfrom=asfrom, **kwargs)
+                    + " "
+                    + self.preparer.format_alias(alias, alias_name)
+                )
+            else:
+                return self.process(alias.element, **kwargs)
+
+    def visit_substring_func(self, func, **kw):
+        s = self.process(func.clauses.clauses[0])
+        start = self.process(func.clauses.clauses[1])
+        if len(func.clauses.clauses) > 2:
+            length = self.process(func.clauses.clauses[2])
+            return "SUBSTRING(%s FROM %s FOR %s)" % (s, start, length)
+        else:
+            return "SUBSTRING(%s FROM %s)" % (s, start)
+
+    def visit_length_func(self, function, **kw):
+        if self.dialect._version_two:
+            return "char_length" + self.function_argspec(function)
+        else:
+            return "strlen" + self.function_argspec(function)
+
+    visit_char_length_func = visit_length_func
+
+    def function_argspec(self, func, **kw):
+        # TODO: this probably will need to be
+        # narrowed to a fixed list, some no-arg functions
+        # may require parens - see similar example in the oracle
+        # dialect
+        if func.clauses is not None and len(func.clauses):
+            return self.process(func.clause_expr, **kw)
+        else:
+            return ""
+
+    def default_from(self):
+        return " FROM rdb$database"
+
+    def visit_sequence(self, seq, **kw):
+        return "gen_id(%s, 1)" % self.preparer.format_sequence(seq)
+
+    def get_select_precolumns(self, select, **kw):
+        """Called when building a ``SELECT`` statement, position is just
+        before column list Firebird puts the limit and offset right
+        after the ``SELECT``...
+        """
+
+        result = ""
+        if select._limit_clause is not None:
+            result += "FIRST %s " % self.process(select._limit_clause, **kw)
+        if select._offset_clause is not None:
+            result += "SKIP %s " % self.process(select._offset_clause, **kw)
+        result += super(FBCompiler, self).get_select_precolumns(select, **kw)
+        return result
+
+    def limit_clause(self, select, **kw):
+        """Already taken care of in the `get_select_precolumns` method."""
+
+        return ""
+
+    def returning_clause(self, stmt, returning_cols):
+        columns = [
+            self._label_returning_column(stmt, c)
+            for c in expression._select_iterables(returning_cols)
+        ]
+
+        return "RETURNING " + ", ".join(columns)
+
+
+class FBDDLCompiler(sql.compiler.DDLCompiler):
+    """Firebird syntactic idiosyncrasies"""
+
+    def visit_create_sequence(self, create):
+        """Generate a ``CREATE GENERATOR`` statement for the sequence."""
+
+        # no syntax for these
+        # https://www.firebirdsql.org/manual/generatorguide-sqlsyntax.html
+        if create.element.start is not None:
+            raise NotImplementedError(
+                "Firebird SEQUENCE doesn't support START WITH"
+            )
+        if create.element.increment is not None:
+            raise NotImplementedError(
+                "Firebird SEQUENCE doesn't support INCREMENT BY"
+            )
+
+        if self.dialect._version_two:
+            return "CREATE SEQUENCE %s" % self.preparer.format_sequence(
+                create.element
+            )
+        else:
+            return "CREATE GENERATOR %s" % self.preparer.format_sequence(
+                create.element
+            )
+
+    def visit_drop_sequence(self, drop):
+        """Generate a ``DROP GENERATOR`` statement for the sequence."""
+
+        if self.dialect._version_two:
+            return "DROP SEQUENCE %s" % self.preparer.format_sequence(
+                drop.element
+            )
+        else:
+            return "DROP GENERATOR %s" % self.preparer.format_sequence(
+                drop.element
+            )
+
+    def visit_computed_column(self, generated):
+        if generated.persisted is not None:
+            raise exc.CompileError(
+                "Firebird computed columns do not support a persistence "
+                "method setting; set the 'persisted' flag to None for "
+                "Firebird support."
+            )
+        return "GENERATED ALWAYS AS (%s)" % self.sql_compiler.process(
+            generated.sqltext, include_table=False, literal_binds=True
+        )
+
+
+class FBIdentifierPreparer(sql.compiler.IdentifierPreparer):
+    """Install Firebird specific reserved words."""
+
+    reserved_words = RESERVED_WORDS
+    illegal_initial_characters = compiler.ILLEGAL_INITIAL_CHARACTERS.union(
+        ["_"]
+    )
+
+    def __init__(self, dialect):
+        super(FBIdentifierPreparer, self).__init__(dialect, omit_schema=True)
+
+
+class FBExecutionContext(default.DefaultExecutionContext):
+    def fire_sequence(self, seq, type_):
+        """Get the next value from the sequence using ``gen_id()``."""
+
+        return self._execute_scalar(
+            "SELECT gen_id(%s, 1) FROM rdb$database"
+            % self.identifier_preparer.format_sequence(seq),
+            type_,
+        )
+
+
+class FBDialect(default.DefaultDialect):
+    """Firebird dialect"""
+
+    name = "firebird"
+    supports_statement_cache = True
+
+    max_identifier_length = 31
+
+    supports_sequences = True
+    sequences_optional = False
+    supports_default_values = True
+    postfetch_lastrowid = False
+
+    supports_native_boolean = False
+
+    requires_name_normalize = True
+    supports_empty_insert = False
+
+    statement_compiler = FBCompiler
+    ddl_compiler = FBDDLCompiler
+    preparer = FBIdentifierPreparer
+    type_compiler = FBTypeCompiler
+    execution_ctx_cls = FBExecutionContext
+
+    colspecs = colspecs
+    ischema_names = ischema_names
+
+    construct_arguments = []
+
+    # defaults to dialect ver. 3,
+    # will be autodetected off upon
+    # first connect
+    _version_two = True
+
+    def __init__(self, *args, **kwargs):
+        util.warn_deprecated(
+            "The firebird dialect is deprecated and will be removed "
+            "in a future version. This dialect is superseded by the external "
+            "dialect https://github.com/pauldex/sqlalchemy-firebird.",
+            version="1.4",
+        )
+        super(FBDialect, self).__init__(*args, **kwargs)
+
+    def initialize(self, connection):
+        super(FBDialect, self).initialize(connection)
+        self._version_two = (
+            "firebird" in self.server_version_info
+            and self.server_version_info >= (2,)
+        ) or (
+            "interbase" in self.server_version_info
+            and self.server_version_info >= (6,)
+        )
+
+        if not self._version_two:
+            # TODO: whatever other pre < 2.0 stuff goes here
+            self.ischema_names = ischema_names.copy()
+            self.ischema_names["TIMESTAMP"] = sqltypes.DATE
+            self.colspecs = {sqltypes.DateTime: sqltypes.DATE}
+
+        self.implicit_returning = self._version_two and self.__dict__.get(
+            "implicit_returning", True
+        )
+
+    def has_table(self, connection, table_name, schema=None):
+        """Return ``True`` if the given table exists, ignoring
+        the `schema`."""
+        self._ensure_has_table_connection(connection)
+
+        tblqry = """
+        SELECT 1 AS has_table FROM rdb$database
+        WHERE EXISTS (SELECT rdb$relation_name
+                      FROM rdb$relations
+                      WHERE rdb$relation_name=?)
+        """
+        c = connection.exec_driver_sql(
+            tblqry, [self.denormalize_name(table_name)]
+        )
+        return c.first() is not None
+
+    def has_sequence(self, connection, sequence_name, schema=None):
+        """Return ``True`` if the given sequence (generator) exists."""
+
+        genqry = """
+        SELECT 1 AS has_sequence FROM rdb$database
+        WHERE EXISTS (SELECT rdb$generator_name
+                      FROM rdb$generators
+                      WHERE rdb$generator_name=?)
+        """
+        c = connection.exec_driver_sql(
+            genqry, [self.denormalize_name(sequence_name)]
+        )
+        return c.first() is not None
+
+    @reflection.cache
+    def get_table_names(self, connection, schema=None, **kw):
+        # there are two queries commonly mentioned for this.
+        # this one, using view_blr, is at the Firebird FAQ among other places:
+        # https://www.firebirdfaq.org/faq174/
+        s = """
+        select rdb$relation_name
+        from rdb$relations
+        where rdb$view_blr is null
+        and (rdb$system_flag is null or rdb$system_flag = 0);
+        """
+
+        # the other query is this one.  It's not clear if there's really
+        # any difference between these two.  This link:
+        # https://www.alberton.info/firebird_sql_meta_info.html#.Ur3vXfZGni8
+        # states them as interchangeable.  Some discussion at [ticket:2898]
+        # SELECT DISTINCT rdb$relation_name
+        # FROM rdb$relation_fields
+        # WHERE rdb$system_flag=0 AND rdb$view_context IS NULL
+
+        return [
+            self.normalize_name(row[0])
+            for row in connection.exec_driver_sql(s)
+        ]
+
+    @reflection.cache
+    def get_view_names(self, connection, schema=None, **kw):
+        # see https://www.firebirdfaq.org/faq174/
+        s = """
+        select rdb$relation_name
+        from rdb$relations
+        where rdb$view_blr is not null
+        and (rdb$system_flag is null or rdb$system_flag = 0);
+        """
+        return [
+            self.normalize_name(row[0])
+            for row in connection.exec_driver_sql(s)
+        ]
+
+    @reflection.cache
+    def get_view_definition(self, connection, view_name, schema=None, **kw):
+        qry = """
+        SELECT rdb$view_source AS view_source
+        FROM rdb$relations
+        WHERE rdb$relation_name=?
+        """
+        rp = connection.exec_driver_sql(
+            qry, [self.denormalize_name(view_name)]
+        )
+        row = rp.first()
+        if row:
+            return row["view_source"]
+        else:
+            return None
+
+    @reflection.cache
+    def get_pk_constraint(self, connection, table_name, schema=None, **kw):
+        # Query to extract the PK/FK constrained fields of the given table
+        keyqry = """
+        SELECT se.rdb$field_name AS fname
+        FROM rdb$relation_constraints rc
+             JOIN rdb$index_segments se ON rc.rdb$index_name=se.rdb$index_name
+        WHERE rc.rdb$constraint_type=? AND rc.rdb$relation_name=?
+        """
+        tablename = self.denormalize_name(table_name)
+        # get primary key fields
+        c = connection.exec_driver_sql(keyqry, ["PRIMARY KEY", tablename])
+        pkfields = [self.normalize_name(r["fname"]) for r in c.fetchall()]
+        return {"constrained_columns": pkfields, "name": None}
+
+    @reflection.cache
+    def get_column_sequence(
+        self, connection, table_name, column_name, schema=None, **kw
+    ):
+        tablename = self.denormalize_name(table_name)
+        colname = self.denormalize_name(column_name)
+        # Heuristic-query to determine the generator associated to a PK field
+        genqry = """
+        SELECT trigdep.rdb$depended_on_name AS fgenerator
+        FROM rdb$dependencies tabdep
+             JOIN rdb$dependencies trigdep
+                  ON tabdep.rdb$dependent_name=trigdep.rdb$dependent_name
+                     AND trigdep.rdb$depended_on_type=14
+                     AND trigdep.rdb$dependent_type=2
+             JOIN rdb$triggers trig ON
+                    trig.rdb$trigger_name=tabdep.rdb$dependent_name
+        WHERE tabdep.rdb$depended_on_name=?
+          AND tabdep.rdb$depended_on_type=0
+          AND trig.rdb$trigger_type=1
+          AND tabdep.rdb$field_name=?
+          AND (SELECT count(*)
+           FROM rdb$dependencies trigdep2
+           WHERE trigdep2.rdb$dependent_name = trigdep.rdb$dependent_name) = 2
+        """
+        genr = connection.exec_driver_sql(genqry, [tablename, colname]).first()
+        if genr is not None:
+            return dict(name=self.normalize_name(genr["fgenerator"]))
+
+    @reflection.cache
+    def get_columns(self, connection, table_name, schema=None, **kw):
+        # Query to extract the details of all the fields of the given table
+        tblqry = """
+        SELECT r.rdb$field_name AS fname,
+                        r.rdb$null_flag AS null_flag,
+                        t.rdb$type_name AS ftype,
+                        f.rdb$field_sub_type AS stype,
+                        f.rdb$field_length/
+                            COALESCE(cs.rdb$bytes_per_character,1) AS flen,
+                        f.rdb$field_precision AS fprec,
+                        f.rdb$field_scale AS fscale,
+                        COALESCE(r.rdb$default_source,
+                                f.rdb$default_source) AS fdefault
+        FROM rdb$relation_fields r
+             JOIN rdb$fields f ON r.rdb$field_source=f.rdb$field_name
+             JOIN rdb$types t
+              ON t.rdb$type=f.rdb$field_type AND
+                    t.rdb$field_name='RDB$FIELD_TYPE'
+             LEFT JOIN rdb$character_sets cs ON
+                    f.rdb$character_set_id=cs.rdb$character_set_id
+        WHERE f.rdb$system_flag=0 AND r.rdb$relation_name=?
+        ORDER BY r.rdb$field_position
+        """
+        # get the PK, used to determine the eventual associated sequence
+        pk_constraint = self.get_pk_constraint(connection, table_name)
+        pkey_cols = pk_constraint["constrained_columns"]
+
+        tablename = self.denormalize_name(table_name)
+        # get all of the fields for this table
+        c = connection.exec_driver_sql(tblqry, [tablename])
+        cols = []
+        while True:
+            row = c.fetchone()
+            if row is None:
+                break
+            name = self.normalize_name(row["fname"])
+            orig_colname = row["fname"]
+
+            # get the data type
+            colspec = row["ftype"].rstrip()
+            coltype = self.ischema_names.get(colspec)
+            if coltype is None:
+                util.warn(
+                    "Did not recognize type '%s' of column '%s'"
+                    % (colspec, name)
+                )
+                coltype = sqltypes.NULLTYPE
+            elif issubclass(coltype, Integer) and row["fprec"] != 0:
+                coltype = NUMERIC(
+                    precision=row["fprec"], scale=row["fscale"] * -1
+                )
+            elif colspec in ("VARYING", "CSTRING"):
+                coltype = coltype(row["flen"])
+            elif colspec == "TEXT":
+                coltype = TEXT(row["flen"])
+            elif colspec == "BLOB":
+                if row["stype"] == 1:
+                    coltype = TEXT()
+                else:
+                    coltype = BLOB()
+            else:
+                coltype = coltype()
+
+            # does it have a default value?
+            defvalue = None
+            if row["fdefault"] is not None:
+                # the value comes down as "DEFAULT 'value'": there may be
+                # more than one whitespace around the "DEFAULT" keyword
+                # and it may also be lower case
+                # (see also https://tracker.firebirdsql.org/browse/CORE-356)
+                defexpr = row["fdefault"].lstrip()
+                assert defexpr[:8].rstrip().upper() == "DEFAULT", (
+                    "Unrecognized default value: %s" % defexpr
+                )
+                defvalue = defexpr[8:].strip()
+                if defvalue == "NULL":
+                    # Redundant
+                    defvalue = None
+            col_d = {
+                "name": name,
+                "type": coltype,
+                "nullable": not bool(row["null_flag"]),
+                "default": defvalue,
+                "autoincrement": "auto",
+            }
+
+            if orig_colname.lower() == orig_colname:
+                col_d["quote"] = True
+
+            # if the PK is a single field, try to see if its linked to
+            # a sequence thru a trigger
+            if len(pkey_cols) == 1 and name == pkey_cols[0]:
+                seq_d = self.get_column_sequence(connection, tablename, name)
+                if seq_d is not None:
+                    col_d["sequence"] = seq_d
+
+            cols.append(col_d)
+        return cols
+
+    @reflection.cache
+    def get_foreign_keys(self, connection, table_name, schema=None, **kw):
+        # Query to extract the details of each UK/FK of the given table
+        fkqry = """
+        SELECT rc.rdb$constraint_name AS cname,
+               cse.rdb$field_name AS fname,
+               ix2.rdb$relation_name AS targetrname,
+               se.rdb$field_name AS targetfname
+        FROM rdb$relation_constraints rc
+             JOIN rdb$indices ix1 ON ix1.rdb$index_name=rc.rdb$index_name
+             JOIN rdb$indices ix2 ON ix2.rdb$index_name=ix1.rdb$foreign_key
+             JOIN rdb$index_segments cse ON
+                        cse.rdb$index_name=ix1.rdb$index_name
+             JOIN rdb$index_segments se
+                  ON se.rdb$index_name=ix2.rdb$index_name
+                     AND se.rdb$field_position=cse.rdb$field_position
+        WHERE rc.rdb$constraint_type=? AND rc.rdb$relation_name=?
+        ORDER BY se.rdb$index_name, se.rdb$field_position
+        """
+        tablename = self.denormalize_name(table_name)
+
+        c = connection.exec_driver_sql(fkqry, ["FOREIGN KEY", tablename])
+        fks = util.defaultdict(
+            lambda: {
+                "name": None,
+                "constrained_columns": [],
+                "referred_schema": None,
+                "referred_table": None,
+                "referred_columns": [],
+            }
+        )
+
+        for row in c:
+            cname = self.normalize_name(row["cname"])
+            fk = fks[cname]
+            if not fk["name"]:
+                fk["name"] = cname
+                fk["referred_table"] = self.normalize_name(row["targetrname"])
+            fk["constrained_columns"].append(self.normalize_name(row["fname"]))
+            fk["referred_columns"].append(
+                self.normalize_name(row["targetfname"])
+            )
+        return list(fks.values())
+
+    @reflection.cache
+    def get_indexes(self, connection, table_name, schema=None, **kw):
+        qry = """
+        SELECT ix.rdb$index_name AS index_name,
+               ix.rdb$unique_flag AS unique_flag,
+               ic.rdb$field_name AS field_name
+        FROM rdb$indices ix
+             JOIN rdb$index_segments ic
+                  ON ix.rdb$index_name=ic.rdb$index_name
+             LEFT OUTER JOIN rdb$relation_constraints
+                  ON rdb$relation_constraints.rdb$index_name =
+                        ic.rdb$index_name
+        WHERE ix.rdb$relation_name=? AND ix.rdb$foreign_key IS NULL
+          AND rdb$relation_constraints.rdb$constraint_type IS NULL
+        ORDER BY index_name, ic.rdb$field_position
+        """
+        c = connection.exec_driver_sql(
+            qry, [self.denormalize_name(table_name)]
+        )
+
+        indexes = util.defaultdict(dict)
+        for row in c:
+            indexrec = indexes[row["index_name"]]
+            if "name" not in indexrec:
+                indexrec["name"] = self.normalize_name(row["index_name"])
+                indexrec["column_names"] = []
+                indexrec["unique"] = bool(row["unique_flag"])
+
+            indexrec["column_names"].append(
+                self.normalize_name(row["field_name"])
+            )
+
+        return list(indexes.values())

lib/sqlalchemy/dialects/firebird/fdb.py

@@ -0,0 +1,112 @@
+# firebird/fdb.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""
+.. dialect:: firebird+fdb
+    :name: fdb
+    :dbapi: pyodbc
+    :connectstring: firebird+fdb://user:password@host:port/path/to/db[?key=value&key=value...]
+    :url: https://pypi.org/project/fdb/
+
+    fdb is a kinterbasdb compatible DBAPI for Firebird.
+
+    .. versionchanged:: 0.9 - The fdb dialect is now the default dialect
+       under the ``firebird://`` URL space, as ``fdb`` is now the official
+       Python driver for Firebird.
+
+Arguments
+----------
+
+The ``fdb`` dialect is based on the
+:mod:`sqlalchemy.dialects.firebird.kinterbasdb` dialect, however does not
+accept every argument that Kinterbasdb does.
+
+* ``enable_rowcount`` - True by default, setting this to False disables
+  the usage of "cursor.rowcount" with the
+  Kinterbasdb dialect, which SQLAlchemy ordinarily calls upon automatically
+  after any UPDATE or DELETE statement.   When disabled, SQLAlchemy's
+  CursorResult will return -1 for result.rowcount.   The rationale here is
+  that Kinterbasdb requires a second round trip to the database when
+  .rowcount is called -  since SQLA's resultproxy automatically closes
+  the cursor after a non-result-returning statement, rowcount must be
+  called, if at all, before the result object is returned.   Additionally,
+  cursor.rowcount may not return correct results with older versions
+  of Firebird, and setting this flag to False will also cause the
+  SQLAlchemy ORM to ignore its usage. The behavior can also be controlled on a
+  per-execution basis using the ``enable_rowcount`` option with
+  :meth:`_engine.Connection.execution_options`::
+
+      conn = engine.connect().execution_options(enable_rowcount=True)
+      r = conn.execute(stmt)
+      print(r.rowcount)
+
+* ``retaining`` - False by default.   Setting this to True will pass the
+  ``retaining=True`` keyword argument to the ``.commit()`` and ``.rollback()``
+  methods of the DBAPI connection, which can improve performance in some
+  situations, but apparently with significant caveats.
+  Please read the fdb and/or kinterbasdb DBAPI documentation in order to
+  understand the implications of this flag.
+
+  .. versionchanged:: 0.9.0 - the ``retaining`` flag defaults to ``False``.
+     In 0.8 it defaulted to ``True``.
+
+  .. seealso::
+
+    https://pythonhosted.org/fdb/usage-guide.html#retaining-transactions
+    - information on the "retaining" flag.
+
+"""  # noqa
+
+from .kinterbasdb import FBDialect_kinterbasdb
+from ... import util
+
+
+class FBDialect_fdb(FBDialect_kinterbasdb):
+    supports_statement_cache = True
+
+    def __init__(self, enable_rowcount=True, retaining=False, **kwargs):
+        super(FBDialect_fdb, self).__init__(
+            enable_rowcount=enable_rowcount, retaining=retaining, **kwargs
+        )
+
+    @classmethod
+    def dbapi(cls):
+        return __import__("fdb")
+
+    def create_connect_args(self, url):
+        opts = url.translate_connect_args(username="user")
+        if opts.get("port"):
+            opts["host"] = "%s/%s" % (opts["host"], opts["port"])
+            del opts["port"]
+        opts.update(url.query)
+
+        util.coerce_kw_type(opts, "type_conv", int)
+
+        return ([], opts)
+
+    def _get_server_version_info(self, connection):
+        """Get the version of the Firebird server used by a connection.
+
+        Returns a tuple of (`major`, `minor`, `build`), three integers
+        representing the version of the attached server.
+        """
+
+        # This is the simpler approach (the other uses the services api),
+        # that for backward compatibility reasons returns a string like
+        #   LI-V6.3.3.12981 Firebird 2.0
+        # where the first version is a fake one resembling the old
+        # Interbase signature.
+
+        isc_info_firebird_version = 103
+        fbconn = connection.connection
+
+        version = fbconn.db_info(isc_info_firebird_version)
+
+        return self._parse_version_info(version)
+
+
+dialect = FBDialect_fdb

lib/sqlalchemy/dialects/firebird/kinterbasdb.py

@@ -0,0 +1,202 @@
+# firebird/kinterbasdb.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""
+.. dialect:: firebird+kinterbasdb
+    :name: kinterbasdb
+    :dbapi: kinterbasdb
+    :connectstring: firebird+kinterbasdb://user:password@host:port/path/to/db[?key=value&key=value...]
+    :url: https://firebirdsql.org/index.php?op=devel&sub=python
+
+Arguments
+----------
+
+The Kinterbasdb backend accepts the ``enable_rowcount`` and ``retaining``
+arguments accepted by the :mod:`sqlalchemy.dialects.firebird.fdb` dialect.
+In addition, it also accepts the following:
+
+* ``type_conv`` - select the kind of mapping done on the types: by default
+  SQLAlchemy uses 200 with Unicode, datetime and decimal support.  See
+  the linked documents below for further information.
+
+* ``concurrency_level`` - set the backend policy with regards to threading
+  issues: by default SQLAlchemy uses policy 1.  See the linked documents
+  below for further information.
+
+.. seealso::
+
+    https://sourceforge.net/projects/kinterbasdb
+
+    https://kinterbasdb.sourceforge.net/dist_docs/usage.html#adv_param_conv_dynamic_type_translation
+
+    https://kinterbasdb.sourceforge.net/dist_docs/usage.html#special_issue_concurrency
+
+"""  # noqa
+
+import decimal
+from re import match
+
+from .base import FBDialect
+from .base import FBExecutionContext
+from ... import types as sqltypes
+from ... import util
+
+
+class _kinterbasdb_numeric(object):
+    def bind_processor(self, dialect):
+        def process(value):
+            if isinstance(value, decimal.Decimal):
+                return str(value)
+            else:
+                return value
+
+        return process
+
+
+class _FBNumeric_kinterbasdb(_kinterbasdb_numeric, sqltypes.Numeric):
+    pass
+
+
+class _FBFloat_kinterbasdb(_kinterbasdb_numeric, sqltypes.Float):
+    pass
+
+
+class FBExecutionContext_kinterbasdb(FBExecutionContext):
+    @property
+    def rowcount(self):
+        if self.execution_options.get(
+            "enable_rowcount", self.dialect.enable_rowcount
+        ):
+            return self.cursor.rowcount
+        else:
+            return -1
+
+
+class FBDialect_kinterbasdb(FBDialect):
+    driver = "kinterbasdb"
+    supports_statement_cache = True
+    supports_sane_rowcount = False
+    supports_sane_multi_rowcount = False
+    execution_ctx_cls = FBExecutionContext_kinterbasdb
+
+    supports_native_decimal = True
+
+    colspecs = util.update_copy(
+        FBDialect.colspecs,
+        {
+            sqltypes.Numeric: _FBNumeric_kinterbasdb,
+            sqltypes.Float: _FBFloat_kinterbasdb,
+        },
+    )
+
+    def __init__(
+        self,
+        type_conv=200,
+        concurrency_level=1,
+        enable_rowcount=True,
+        retaining=False,
+        **kwargs
+    ):
+        super(FBDialect_kinterbasdb, self).__init__(**kwargs)
+        self.enable_rowcount = enable_rowcount
+        self.type_conv = type_conv
+        self.concurrency_level = concurrency_level
+        self.retaining = retaining
+        if enable_rowcount:
+            self.supports_sane_rowcount = True
+
+    @classmethod
+    def dbapi(cls):
+        return __import__("kinterbasdb")
+
+    def do_execute(self, cursor, statement, parameters, context=None):
+        # kinterbase does not accept a None, but wants an empty list
+        # when there are no arguments.
+        cursor.execute(statement, parameters or [])
+
+    def do_rollback(self, dbapi_connection):
+        dbapi_connection.rollback(self.retaining)
+
+    def do_commit(self, dbapi_connection):
+        dbapi_connection.commit(self.retaining)
+
+    def create_connect_args(self, url):
+        opts = url.translate_connect_args(username="user")
+        if opts.get("port"):
+            opts["host"] = "%s/%s" % (opts["host"], opts["port"])
+            del opts["port"]
+        opts.update(url.query)
+
+        util.coerce_kw_type(opts, "type_conv", int)
+
+        type_conv = opts.pop("type_conv", self.type_conv)
+        concurrency_level = opts.pop(
+            "concurrency_level", self.concurrency_level
+        )
+
+        if self.dbapi is not None:
+            initialized = getattr(self.dbapi, "initialized", None)
+            if initialized is None:
+                # CVS rev 1.96 changed the name of the attribute:
+                # https://kinterbasdb.cvs.sourceforge.net/viewvc/kinterbasdb/
+                # Kinterbasdb-3.0/__init__.py?r1=1.95&r2=1.96
+                initialized = getattr(self.dbapi, "_initialized", False)
+            if not initialized:
+                self.dbapi.init(
+                    type_conv=type_conv, concurrency_level=concurrency_level
+                )
+        return ([], opts)
+
+    def _get_server_version_info(self, connection):
+        """Get the version of the Firebird server used by a connection.
+
+        Returns a tuple of (`major`, `minor`, `build`), three integers
+        representing the version of the attached server.
+        """
+
+        # This is the simpler approach (the other uses the services api),
+        # that for backward compatibility reasons returns a string like
+        #   LI-V6.3.3.12981 Firebird 2.0
+        # where the first version is a fake one resembling the old
+        # Interbase signature.
+
+        fbconn = connection.connection
+        version = fbconn.server_version
+
+        return self._parse_version_info(version)
+
+    def _parse_version_info(self, version):
+        m = match(
+            r"\w+-V(\d+)\.(\d+)\.(\d+)\.(\d+)( \w+ (\d+)\.(\d+))?", version
+        )
+        if not m:
+            raise AssertionError(
+                "Could not determine version from string '%s'" % version
+            )
+
+        if m.group(5) != None:
+            return tuple([int(x) for x in m.group(6, 7, 4)] + ["firebird"])
+        else:
+            return tuple([int(x) for x in m.group(1, 2, 3)] + ["interbase"])
+
+    def is_disconnect(self, e, connection, cursor):
+        if isinstance(
+            e, (self.dbapi.OperationalError, self.dbapi.ProgrammingError)
+        ):
+            msg = str(e)
+            return (
+                "Error writing data to the connection" in msg
+                or "Unable to complete network request to host" in msg
+                or "Invalid connection state" in msg
+                or "Invalid cursor state" in msg
+                or "connection shutdown" in msg
+            )
+        else:
+            return False
+
+
+dialect = FBDialect_kinterbasdb

lib/sqlalchemy/dialects/mssql/__init__.py

@@ -0,0 +1,85 @@
+# mssql/__init__.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from . import base  # noqa
+from . import mxodbc  # noqa
+from . import pymssql  # noqa
+from . import pyodbc  # noqa
+from .base import BIGINT
+from .base import BINARY
+from .base import BIT
+from .base import CHAR
+from .base import DATE
+from .base import DATETIME
+from .base import DATETIME2
+from .base import DATETIMEOFFSET
+from .base import DECIMAL
+from .base import FLOAT
+from .base import IMAGE
+from .base import INTEGER
+from .base import JSON
+from .base import MONEY
+from .base import NCHAR
+from .base import NTEXT
+from .base import NUMERIC
+from .base import NVARCHAR
+from .base import REAL
+from .base import ROWVERSION
+from .base import SMALLDATETIME
+from .base import SMALLINT
+from .base import SMALLMONEY
+from .base import SQL_VARIANT
+from .base import TEXT
+from .base import TIME
+from .base import TIMESTAMP
+from .base import TINYINT
+from .base import try_cast
+from .base import UNIQUEIDENTIFIER
+from .base import VARBINARY
+from .base import VARCHAR
+from .base import XML
+
+
+base.dialect = dialect = pyodbc.dialect
+
+
+__all__ = (
+    "JSON",
+    "INTEGER",
+    "BIGINT",
+    "SMALLINT",
+    "TINYINT",
+    "VARCHAR",
+    "NVARCHAR",
+    "CHAR",
+    "NCHAR",
+    "TEXT",
+    "NTEXT",
+    "DECIMAL",
+    "NUMERIC",
+    "FLOAT",
+    "DATETIME",
+    "DATETIME2",
+    "DATETIMEOFFSET",
+    "DATE",
+    "TIME",
+    "SMALLDATETIME",
+    "BINARY",
+    "VARBINARY",
+    "BIT",
+    "REAL",
+    "IMAGE",
+    "TIMESTAMP",
+    "ROWVERSION",
+    "MONEY",
+    "SMALLMONEY",
+    "UNIQUEIDENTIFIER",
+    "SQL_VARIANT",
+    "XML",
+    "dialect",
+    "try_cast",
+)

lib/sqlalchemy/dialects/mssql/information_schema.py

@@ -0,0 +1,232 @@
+# mssql/information_schema.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from ... import cast
+from ... import Column
+from ... import MetaData
+from ... import Table
+from ... import util
+from ...ext.compiler import compiles
+from ...sql import expression
+from ...types import Boolean
+from ...types import Integer
+from ...types import Numeric
+from ...types import String
+from ...types import TypeDecorator
+from ...types import Unicode
+
+
+ischema = MetaData()
+
+
+class CoerceUnicode(TypeDecorator):
+    impl = Unicode
+    cache_ok = True
+
+    def process_bind_param(self, value, dialect):
+        if util.py2k and isinstance(value, util.binary_type):
+            value = value.decode(dialect.encoding)
+        return value
+
+    def bind_expression(self, bindvalue):
+        return _cast_on_2005(bindvalue)
+
+
+class _cast_on_2005(expression.ColumnElement):
+    def __init__(self, bindvalue):
+        self.bindvalue = bindvalue
+
+
+@compiles(_cast_on_2005)
+def _compile(element, compiler, **kw):
+    from . import base
+
+    if (
+        compiler.dialect.server_version_info is None
+        or compiler.dialect.server_version_info < base.MS_2005_VERSION
+    ):
+        return compiler.process(element.bindvalue, **kw)
+    else:
+        return compiler.process(cast(element.bindvalue, Unicode), **kw)
+
+
+schemata = Table(
+    "SCHEMATA",
+    ischema,
+    Column("CATALOG_NAME", CoerceUnicode, key="catalog_name"),
+    Column("SCHEMA_NAME", CoerceUnicode, key="schema_name"),
+    Column("SCHEMA_OWNER", CoerceUnicode, key="schema_owner"),
+    schema="INFORMATION_SCHEMA",
+)
+
+tables = Table(
+    "TABLES",
+    ischema,
+    Column("TABLE_CATALOG", CoerceUnicode, key="table_catalog"),
+    Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"),
+    Column("TABLE_NAME", CoerceUnicode, key="table_name"),
+    Column("TABLE_TYPE", CoerceUnicode, key="table_type"),
+    schema="INFORMATION_SCHEMA",
+)
+
+columns = Table(
+    "COLUMNS",
+    ischema,
+    Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"),
+    Column("TABLE_NAME", CoerceUnicode, key="table_name"),
+    Column("COLUMN_NAME", CoerceUnicode, key="column_name"),
+    Column("IS_NULLABLE", Integer, key="is_nullable"),
+    Column("DATA_TYPE", String, key="data_type"),
+    Column("ORDINAL_POSITION", Integer, key="ordinal_position"),
+    Column(
+        "CHARACTER_MAXIMUM_LENGTH", Integer, key="character_maximum_length"
+    ),
+    Column("NUMERIC_PRECISION", Integer, key="numeric_precision"),
+    Column("NUMERIC_SCALE", Integer, key="numeric_scale"),
+    Column("COLUMN_DEFAULT", Integer, key="column_default"),
+    Column("COLLATION_NAME", String, key="collation_name"),
+    schema="INFORMATION_SCHEMA",
+)
+
+mssql_temp_table_columns = Table(
+    "COLUMNS",
+    ischema,
+    Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"),
+    Column("TABLE_NAME", CoerceUnicode, key="table_name"),
+    Column("COLUMN_NAME", CoerceUnicode, key="column_name"),
+    Column("IS_NULLABLE", Integer, key="is_nullable"),
+    Column("DATA_TYPE", String, key="data_type"),
+    Column("ORDINAL_POSITION", Integer, key="ordinal_position"),
+    Column(
+        "CHARACTER_MAXIMUM_LENGTH", Integer, key="character_maximum_length"
+    ),
+    Column("NUMERIC_PRECISION", Integer, key="numeric_precision"),
+    Column("NUMERIC_SCALE", Integer, key="numeric_scale"),
+    Column("COLUMN_DEFAULT", Integer, key="column_default"),
+    Column("COLLATION_NAME", String, key="collation_name"),
+    schema="tempdb.INFORMATION_SCHEMA",
+)
+
+constraints = Table(
+    "TABLE_CONSTRAINTS",
+    ischema,
+    Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"),
+    Column("TABLE_NAME", CoerceUnicode, key="table_name"),
+    Column("CONSTRAINT_NAME", CoerceUnicode, key="constraint_name"),
+    Column("CONSTRAINT_TYPE", CoerceUnicode, key="constraint_type"),
+    schema="INFORMATION_SCHEMA",
+)
+
+column_constraints = Table(
+    "CONSTRAINT_COLUMN_USAGE",
+    ischema,
+    Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"),
+    Column("TABLE_NAME", CoerceUnicode, key="table_name"),
+    Column("COLUMN_NAME", CoerceUnicode, key="column_name"),
+    Column("CONSTRAINT_NAME", CoerceUnicode, key="constraint_name"),
+    schema="INFORMATION_SCHEMA",
+)
+
+key_constraints = Table(
+    "KEY_COLUMN_USAGE",
+    ischema,
+    Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"),
+    Column("TABLE_NAME", CoerceUnicode, key="table_name"),
+    Column("COLUMN_NAME", CoerceUnicode, key="column_name"),
+    Column("CONSTRAINT_NAME", CoerceUnicode, key="constraint_name"),
+    Column("CONSTRAINT_SCHEMA", CoerceUnicode, key="constraint_schema"),
+    Column("ORDINAL_POSITION", Integer, key="ordinal_position"),
+    schema="INFORMATION_SCHEMA",
+)
+
+ref_constraints = Table(
+    "REFERENTIAL_CONSTRAINTS",
+    ischema,
+    Column("CONSTRAINT_CATALOG", CoerceUnicode, key="constraint_catalog"),
+    Column("CONSTRAINT_SCHEMA", CoerceUnicode, key="constraint_schema"),
+    Column("CONSTRAINT_NAME", CoerceUnicode, key="constraint_name"),
+    # TODO: is CATLOG misspelled ?
+    Column(
+        "UNIQUE_CONSTRAINT_CATLOG",
+        CoerceUnicode,
+        key="unique_constraint_catalog",
+    ),
+    Column(
+        "UNIQUE_CONSTRAINT_SCHEMA",
+        CoerceUnicode,
+        key="unique_constraint_schema",
+    ),
+    Column(
+        "UNIQUE_CONSTRAINT_NAME", CoerceUnicode, key="unique_constraint_name"
+    ),
+    Column("MATCH_OPTION", String, key="match_option"),
+    Column("UPDATE_RULE", String, key="update_rule"),
+    Column("DELETE_RULE", String, key="delete_rule"),
+    schema="INFORMATION_SCHEMA",
+)
+
+views = Table(
+    "VIEWS",
+    ischema,
+    Column("TABLE_CATALOG", CoerceUnicode, key="table_catalog"),
+    Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"),
+    Column("TABLE_NAME", CoerceUnicode, key="table_name"),
+    Column("VIEW_DEFINITION", CoerceUnicode, key="view_definition"),
+    Column("CHECK_OPTION", String, key="check_option"),
+    Column("IS_UPDATABLE", String, key="is_updatable"),
+    schema="INFORMATION_SCHEMA",
+)
+
+computed_columns = Table(
+    "computed_columns",
+    ischema,
+    Column("object_id", Integer),
+    Column("name", CoerceUnicode),
+    Column("is_computed", Boolean),
+    Column("is_persisted", Boolean),
+    Column("definition", CoerceUnicode),
+    schema="sys",
+)
+
+sequences = Table(
+    "SEQUENCES",
+    ischema,
+    Column("SEQUENCE_CATALOG", CoerceUnicode, key="sequence_catalog"),
+    Column("SEQUENCE_SCHEMA", CoerceUnicode, key="sequence_schema"),
+    Column("SEQUENCE_NAME", CoerceUnicode, key="sequence_name"),
+    schema="INFORMATION_SCHEMA",
+)
+
+
+class IdentitySqlVariant(TypeDecorator):
+    r"""This type casts sql_variant columns in the identity_columns view
+    to numeric. This is required because:
+
+    * pyodbc does not support sql_variant
+    * pymssql under python 2 return the byte representation of the number,
+      int 1 is returned as "\x01\x00\x00\x00". On python 3 it returns the
+      correct value as string.
+    """
+    impl = Unicode
+    cache_ok = True
+
+    def column_expression(self, colexpr):
+        return cast(colexpr, Numeric)
+
+
+identity_columns = Table(
+    "identity_columns",
+    ischema,
+    Column("object_id", Integer),
+    Column("name", CoerceUnicode),
+    Column("is_identity", Boolean),
+    Column("seed_value", IdentitySqlVariant),
+    Column("increment_value", IdentitySqlVariant),
+    Column("last_value", IdentitySqlVariant),
+    Column("is_not_for_replication", Boolean),
+    schema="sys",
+)

lib/sqlalchemy/dialects/mssql/json.py

@@ -0,0 +1,125 @@
+from ... import types as sqltypes
+
+# technically, all the dialect-specific datatypes that don't have any special
+# behaviors would be private with names like _MSJson. However, we haven't been
+# doing this for mysql.JSON or sqlite.JSON which both have JSON / JSONIndexType
+# / JSONPathType in their json.py files, so keep consistent with that
+# sub-convention for now.  A future change can update them all to be
+# package-private at once.
+
+
+class JSON(sqltypes.JSON):
+    """MSSQL JSON type.
+
+    MSSQL supports JSON-formatted data as of SQL Server 2016.
+
+    The :class:`_mssql.JSON` datatype at the DDL level will represent the
+    datatype as ``NVARCHAR(max)``, but provides for JSON-level comparison
+    functions as well as Python coercion behavior.
+
+    :class:`_mssql.JSON` is used automatically whenever the base
+    :class:`_types.JSON` datatype is used against a SQL Server backend.
+
+    .. seealso::
+
+        :class:`_types.JSON` - main documentation for the generic
+        cross-platform JSON datatype.
+
+    The :class:`_mssql.JSON` type supports persistence of JSON values
+    as well as the core index operations provided by :class:`_types.JSON`
+    datatype, by adapting the operations to render the ``JSON_VALUE``
+    or ``JSON_QUERY`` functions at the database level.
+
+    The SQL Server :class:`_mssql.JSON` type necessarily makes use of the
+    ``JSON_QUERY`` and ``JSON_VALUE`` functions when querying for elements
+    of a JSON object.   These two functions have a major restriction in that
+    they are **mutually exclusive** based on the type of object to be returned.
+    The ``JSON_QUERY`` function **only** returns a JSON dictionary or list,
+    but not an individual string, numeric, or boolean element; the
+    ``JSON_VALUE`` function **only** returns an individual string, numeric,
+    or boolean element.   **both functions either return NULL or raise
+    an error if they are not used against the correct expected value**.
+
+    To handle this awkward requirement, indexed access rules are as follows:
+
+    1. When extracting a sub element from a JSON that is itself a JSON
+       dictionary or list, the :meth:`_types.JSON.Comparator.as_json` accessor
+       should be used::
+
+            stmt = select(
+                data_table.c.data["some key"].as_json()
+            ).where(
+                data_table.c.data["some key"].as_json() == {"sub": "structure"}
+            )
+
+    2. When extracting a sub element from a JSON that is a plain boolean,
+       string, integer, or float, use the appropriate method among
+       :meth:`_types.JSON.Comparator.as_boolean`,
+       :meth:`_types.JSON.Comparator.as_string`,
+       :meth:`_types.JSON.Comparator.as_integer`,
+       :meth:`_types.JSON.Comparator.as_float`::
+
+            stmt = select(
+                data_table.c.data["some key"].as_string()
+            ).where(
+                data_table.c.data["some key"].as_string() == "some string"
+            )
+
+    .. versionadded:: 1.4
+
+
+    """
+
+    # note there was a result processor here that was looking for "number",
+    # but none of the tests seem to exercise it.
+
+
+# Note: these objects currently match exactly those of MySQL, however since
+# these are not generalizable to all JSON implementations, remain separately
+# implemented for each dialect.
+class _FormatTypeMixin(object):
+    def _format_value(self, value):
+        raise NotImplementedError()
+
+    def bind_processor(self, dialect):
+        super_proc = self.string_bind_processor(dialect)
+
+        def process(value):
+            value = self._format_value(value)
+            if super_proc:
+                value = super_proc(value)
+            return value
+
+        return process
+
+    def literal_processor(self, dialect):
+        super_proc = self.string_literal_processor(dialect)
+
+        def process(value):
+            value = self._format_value(value)
+            if super_proc:
+                value = super_proc(value)
+            return value
+
+        return process
+
+
+class JSONIndexType(_FormatTypeMixin, sqltypes.JSON.JSONIndexType):
+    def _format_value(self, value):
+        if isinstance(value, int):
+            value = "$[%s]" % value
+        else:
+            value = '$."%s"' % value
+        return value
+
+
+class JSONPathType(_FormatTypeMixin, sqltypes.JSON.JSONPathType):
+    def _format_value(self, value):
+        return "$%s" % (
+            "".join(
+                [
+                    "[%s]" % elem if isinstance(elem, int) else '."%s"' % elem
+                    for elem in value
+                ]
+            )
+        )

lib/sqlalchemy/dialects/mssql/mxodbc.py

@@ -0,0 +1,150 @@
+# mssql/mxodbc.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""
+.. dialect:: mssql+mxodbc
+    :name: mxODBC
+    :dbapi: mxodbc
+    :connectstring: mssql+mxodbc://<username>:<password>@<dsnname>
+    :url: https://www.egenix.com/
+
+.. deprecated:: 1.4 The mxODBC DBAPI is deprecated and will be removed
+   in a future version. Please use one of the supported DBAPIs to
+   connect to mssql.
+
+Execution Modes
+---------------
+
+mxODBC features two styles of statement execution, using the
+``cursor.execute()`` and ``cursor.executedirect()`` methods (the second being
+an extension to the DBAPI specification). The former makes use of a particular
+API call specific to the SQL Server Native Client ODBC driver known
+SQLDescribeParam, while the latter does not.
+
+mxODBC apparently only makes repeated use of a single prepared statement
+when SQLDescribeParam is used. The advantage to prepared statement reuse is
+one of performance. The disadvantage is that SQLDescribeParam has a limited
+set of scenarios in which bind parameters are understood, including that they
+cannot be placed within the argument lists of function calls, anywhere outside
+the FROM, or even within subqueries within the FROM clause - making the usage
+of bind parameters within SELECT statements impossible for all but the most
+simplistic statements.
+
+For this reason, the mxODBC dialect uses the "native" mode by default only for
+INSERT, UPDATE, and DELETE statements, and uses the escaped string mode for
+all other statements.
+
+This behavior can be controlled via
+:meth:`~sqlalchemy.sql.expression.Executable.execution_options` using the
+``native_odbc_execute`` flag with a value of ``True`` or ``False``, where a
+value of ``True`` will unconditionally use native bind parameters and a value
+of ``False`` will unconditionally use string-escaped parameters.
+
+"""
+
+
+from .base import _MSDate
+from .base import _MSDateTime
+from .base import _MSTime
+from .base import MSDialect
+from .base import VARBINARY
+from .pyodbc import _MSNumeric_pyodbc
+from .pyodbc import MSExecutionContext_pyodbc
+from ... import types as sqltypes
+from ...connectors.mxodbc import MxODBCConnector
+
+
+class _MSNumeric_mxodbc(_MSNumeric_pyodbc):
+    """Include pyodbc's numeric processor."""
+
+
+class _MSDate_mxodbc(_MSDate):
+    def bind_processor(self, dialect):
+        def process(value):
+            if value is not None:
+                return "%s-%s-%s" % (value.year, value.month, value.day)
+            else:
+                return None
+
+        return process
+
+
+class _MSTime_mxodbc(_MSTime):
+    def bind_processor(self, dialect):
+        def process(value):
+            if value is not None:
+                return "%s:%s:%s" % (value.hour, value.minute, value.second)
+            else:
+                return None
+
+        return process
+
+
+class _VARBINARY_mxodbc(VARBINARY):
+
+    """
+    mxODBC Support for VARBINARY column types.
+
+    This handles the special case for null VARBINARY values,
+    which maps None values to the mx.ODBC.Manager.BinaryNull symbol.
+    """
+
+    def bind_processor(self, dialect):
+        if dialect.dbapi is None:
+            return None
+
+        DBAPIBinary = dialect.dbapi.Binary
+
+        def process(value):
+            if value is not None:
+                return DBAPIBinary(value)
+            else:
+                # should pull from mx.ODBC.Manager.BinaryNull
+                return dialect.dbapi.BinaryNull
+
+        return process
+
+
+class MSExecutionContext_mxodbc(MSExecutionContext_pyodbc):
+    """
+    The pyodbc execution context is useful for enabling
+    SELECT SCOPE_IDENTITY in cases where OUTPUT clause
+    does not work (tables with insert triggers).
+    """
+
+    # todo - investigate whether the pyodbc execution context
+    #       is really only being used in cases where OUTPUT
+    #       won't work.
+
+
+class MSDialect_mxodbc(MxODBCConnector, MSDialect):
+
+    # this is only needed if "native ODBC" mode is used,
+    # which is now disabled by default.
+    # statement_compiler = MSSQLStrictCompiler
+    supports_statement_cache = True
+
+    execution_ctx_cls = MSExecutionContext_mxodbc
+
+    # flag used by _MSNumeric_mxodbc
+    _need_decimal_fix = True
+
+    colspecs = {
+        sqltypes.Numeric: _MSNumeric_mxodbc,
+        sqltypes.DateTime: _MSDateTime,
+        sqltypes.Date: _MSDate_mxodbc,
+        sqltypes.Time: _MSTime_mxodbc,
+        VARBINARY: _VARBINARY_mxodbc,
+        sqltypes.LargeBinary: _VARBINARY_mxodbc,
+    }
+
+    def __init__(self, description_encoding=None, **params):
+        super(MSDialect_mxodbc, self).__init__(**params)
+        self.description_encoding = description_encoding
+
+
+dialect = MSDialect_mxodbc

lib/sqlalchemy/dialects/mssql/provision.py

@@ -0,0 +1,116 @@
+from sqlalchemy import inspect
+from sqlalchemy import Integer
+from ... import create_engine
+from ... import exc
+from ...schema import Column
+from ...schema import DropConstraint
+from ...schema import ForeignKeyConstraint
+from ...schema import MetaData
+from ...schema import Table
+from ...testing.provision import create_db
+from ...testing.provision import drop_all_schema_objects_pre_tables
+from ...testing.provision import drop_db
+from ...testing.provision import get_temp_table_name
+from ...testing.provision import log
+from ...testing.provision import run_reap_dbs
+from ...testing.provision import temp_table_keyword_args
+
+
+@create_db.for_db("mssql")
+def _mssql_create_db(cfg, eng, ident):
+    with eng.connect().execution_options(isolation_level="AUTOCOMMIT") as conn:
+        conn.exec_driver_sql("create database %s" % ident)
+        conn.exec_driver_sql(
+            "ALTER DATABASE %s SET ALLOW_SNAPSHOT_ISOLATION ON" % ident
+        )
+        conn.exec_driver_sql(
+            "ALTER DATABASE %s SET READ_COMMITTED_SNAPSHOT ON" % ident
+        )
+        conn.exec_driver_sql("use %s" % ident)
+        conn.exec_driver_sql("create schema test_schema")
+        conn.exec_driver_sql("create schema test_schema_2")
+
+
+@drop_db.for_db("mssql")
+def _mssql_drop_db(cfg, eng, ident):
+    with eng.connect().execution_options(isolation_level="AUTOCOMMIT") as conn:
+        _mssql_drop_ignore(conn, ident)
+
+
+def _mssql_drop_ignore(conn, ident):
+    try:
+        # typically when this happens, we can't KILL the session anyway,
+        # so let the cleanup process drop the DBs
+        # for row in conn.exec_driver_sql(
+        #     "select session_id from sys.dm_exec_sessions "
+        #        "where database_id=db_id('%s')" % ident):
+        #    log.info("killing SQL server session %s", row['session_id'])
+        #    conn.exec_driver_sql("kill %s" % row['session_id'])
+        conn.exec_driver_sql("drop database %s" % ident)
+        log.info("Reaped db: %s", ident)
+        return True
+    except exc.DatabaseError as err:
+        log.warning("couldn't drop db: %s", err)
+        return False
+
+
+@run_reap_dbs.for_db("mssql")
+def _reap_mssql_dbs(url, idents):
+    log.info("db reaper connecting to %r", url)
+    eng = create_engine(url)
+    with eng.connect().execution_options(isolation_level="AUTOCOMMIT") as conn:
+
+        log.info("identifiers in file: %s", ", ".join(idents))
+
+        to_reap = conn.exec_driver_sql(
+            "select d.name from sys.databases as d where name "
+            "like 'TEST_%' and not exists (select session_id "
+            "from sys.dm_exec_sessions "
+            "where database_id=d.database_id)"
+        )
+        all_names = {dbname.lower() for (dbname,) in to_reap}
+        to_drop = set()
+        for name in all_names:
+            if name in idents:
+                to_drop.add(name)
+
+        dropped = total = 0
+        for total, dbname in enumerate(to_drop, 1):
+            if _mssql_drop_ignore(conn, dbname):
+                dropped += 1
+        log.info(
+            "Dropped %d out of %d stale databases detected", dropped, total
+        )
+
+
+@temp_table_keyword_args.for_db("mssql")
+def _mssql_temp_table_keyword_args(cfg, eng):
+    return {}
+
+
+@get_temp_table_name.for_db("mssql")
+def _mssql_get_temp_table_name(cfg, eng, base_name):
+    return "##" + base_name
+
+
+@drop_all_schema_objects_pre_tables.for_db("mssql")
+def drop_all_schema_objects_pre_tables(cfg, eng):
+    with eng.connect().execution_options(isolation_level="AUTOCOMMIT") as conn:
+        inspector = inspect(conn)
+        for schema in (None, "dbo", cfg.test_schema, cfg.test_schema_2):
+            for tname in inspector.get_table_names(schema=schema):
+                tb = Table(
+                    tname,
+                    MetaData(),
+                    Column("x", Integer),
+                    Column("y", Integer),
+                    schema=schema,
+                )
+                for fk in inspect(conn).get_foreign_keys(tname, schema=schema):
+                    conn.execute(
+                        DropConstraint(
+                            ForeignKeyConstraint(
+                                [tb.c.x], [tb.c.y], name=fk["name"]
+                            )
+                        )
+                    )

lib/sqlalchemy/dialects/mssql/pymssql.py

@@ -0,0 +1,138 @@
+# mssql/pymssql.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""
+.. dialect:: mssql+pymssql
+    :name: pymssql
+    :dbapi: pymssql
+    :connectstring: mssql+pymssql://<username>:<password>@<freetds_name>/?charset=utf8
+
+pymssql is a Python module that provides a Python DBAPI interface around
+`FreeTDS <https://www.freetds.org/>`_.
+
+.. note::
+
+    pymssql is currently not included in SQLAlchemy's continuous integration
+    (CI) testing.
+
+Modern versions of this driver worked very well with SQL Server and FreeTDS
+from Linux and were highly recommended. However, pymssql is currently
+unmaintained and has fallen behind the progress of the Microsoft ODBC driver in
+its support for newer features of SQL Server. The latest official release of
+pymssql at the time of this document is version 2.1.4 (August, 2018) and it
+lacks support for:
+
+1. table-valued parameters (TVPs),
+2. ``datetimeoffset`` columns using timezone-aware ``datetime`` objects
+   (values are sent and retrieved as strings), and
+3. encrypted connections (e.g., to Azure SQL), when pymssql is installed from
+   the pre-built wheels. Support for encrypted connections requires building
+   pymssql from source, which can be a nuisance, especially under Windows.
+
+The above features are all supported by mssql+pyodbc when using Microsoft's
+ODBC Driver for SQL Server (msodbcsql), which is now available for Windows,
+(several flavors of) Linux, and macOS.
+
+
+"""  # noqa
+import re
+
+from .base import MSDialect
+from .base import MSIdentifierPreparer
+from ... import processors
+from ... import types as sqltypes
+from ... import util
+
+
+class _MSNumeric_pymssql(sqltypes.Numeric):
+    def result_processor(self, dialect, type_):
+        if not self.asdecimal:
+            return processors.to_float
+        else:
+            return sqltypes.Numeric.result_processor(self, dialect, type_)
+
+
+class MSIdentifierPreparer_pymssql(MSIdentifierPreparer):
+    def __init__(self, dialect):
+        super(MSIdentifierPreparer_pymssql, self).__init__(dialect)
+        # pymssql has the very unusual behavior that it uses pyformat
+        # yet does not require that percent signs be doubled
+        self._double_percents = False
+
+
+class MSDialect_pymssql(MSDialect):
+    supports_statement_cache = True
+    supports_native_decimal = True
+    driver = "pymssql"
+
+    preparer = MSIdentifierPreparer_pymssql
+
+    colspecs = util.update_copy(
+        MSDialect.colspecs,
+        {sqltypes.Numeric: _MSNumeric_pymssql, sqltypes.Float: sqltypes.Float},
+    )
+
+    @classmethod
+    def dbapi(cls):
+        module = __import__("pymssql")
+        # pymmsql < 2.1.1 doesn't have a Binary method.  we use string
+        client_ver = tuple(int(x) for x in module.__version__.split("."))
+        if client_ver < (2, 1, 1):
+            # TODO: monkeypatching here is less than ideal
+            module.Binary = lambda x: x if hasattr(x, "decode") else str(x)
+
+        if client_ver < (1,):
+            util.warn(
+                "The pymssql dialect expects at least "
+                "the 1.0 series of the pymssql DBAPI."
+            )
+        return module
+
+    def _get_server_version_info(self, connection):
+        vers = connection.exec_driver_sql("select @@version").scalar()
+        m = re.match(r"Microsoft .*? - (\d+)\.(\d+)\.(\d+)\.(\d+)", vers)
+        if m:
+            return tuple(int(x) for x in m.group(1, 2, 3, 4))
+        else:
+            return None
+
+    def create_connect_args(self, url):
+        opts = url.translate_connect_args(username="user")
+        opts.update(url.query)
+        port = opts.pop("port", None)
+        if port and "host" in opts:
+            opts["host"] = "%s:%s" % (opts["host"], port)
+        return [[], opts]
+
+    def is_disconnect(self, e, connection, cursor):
+        for msg in (
+            "Adaptive Server connection timed out",
+            "Net-Lib error during Connection reset by peer",
+            "message 20003",  # connection timeout
+            "Error 10054",
+            "Not connected to any MS SQL server",
+            "Connection is closed",
+            "message 20006",  # Write to the server failed
+            "message 20017",  # Unexpected EOF from the server
+            "message 20047",  # DBPROCESS is dead or not enabled
+        ):
+            if msg in str(e):
+                return True
+        else:
+            return False
+
+    def set_isolation_level(self, connection, level):
+        if level == "AUTOCOMMIT":
+            connection.autocommit(True)
+        else:
+            connection.autocommit(False)
+            super(MSDialect_pymssql, self).set_isolation_level(
+                connection, level
+            )
+
+
+dialect = MSDialect_pymssql

lib/sqlalchemy/dialects/mssql/pyodbc.py

@@ -0,0 +1,673 @@
+# mssql/pyodbc.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+r"""
+.. dialect:: mssql+pyodbc
+    :name: PyODBC
+    :dbapi: pyodbc
+    :connectstring: mssql+pyodbc://<username>:<password>@<dsnname>
+    :url: https://pypi.org/project/pyodbc/
+
+Connecting to PyODBC
+--------------------
+
+The URL here is to be translated to PyODBC connection strings, as
+detailed in `ConnectionStrings <https://code.google.com/p/pyodbc/wiki/ConnectionStrings>`_.
+
+DSN Connections
+^^^^^^^^^^^^^^^
+
+A DSN connection in ODBC means that a pre-existing ODBC datasource is
+configured on the client machine.   The application then specifies the name
+of this datasource, which encompasses details such as the specific ODBC driver
+in use as well as the network address of the database.   Assuming a datasource
+is configured on the client, a basic DSN-based connection looks like::
+
+    engine = create_engine("mssql+pyodbc://scott:tiger@some_dsn")
+
+Which above, will pass the following connection string to PyODBC::
+
+    DSN=some_dsn;UID=scott;PWD=tiger
+
+If the username and password are omitted, the DSN form will also add
+the ``Trusted_Connection=yes`` directive to the ODBC string.
+
+Hostname Connections
+^^^^^^^^^^^^^^^^^^^^
+
+Hostname-based connections are also supported by pyodbc.  These are often
+easier to use than a DSN and have the additional advantage that the specific
+database name to connect towards may be specified locally in the URL, rather
+than it being fixed as part of a datasource configuration.
+
+When using a hostname connection, the driver name must also be specified in the
+query parameters of the URL.  As these names usually have spaces in them, the
+name must be URL encoded which means using plus signs for spaces::
+
+    engine = create_engine("mssql+pyodbc://scott:tiger@myhost:port/databasename?driver=ODBC+Driver+17+for+SQL+Server")
+
+Other keywords interpreted by the Pyodbc dialect to be passed to
+``pyodbc.connect()`` in both the DSN and hostname cases include:
+``odbc_autotranslate``, ``ansi``, ``unicode_results``, ``autocommit``,
+``authentication``.
+Note that in order for the dialect to recognize these keywords
+(including the ``driver`` keyword above) they must be all lowercase.
+Multiple additional keyword arguments must be separated by an
+ampersand (``&``), not a semicolon::
+
+    engine = create_engine(
+        "mssql+pyodbc://scott:tiger@myhost:49242/databasename"
+        "?driver=ODBC+Driver+17+for+SQL+Server"
+        "&authentication=ActiveDirectoryIntegrated"
+    )
+
+The equivalent URL can be constructed using :class:`_sa.engine.URL`::
+
+    from sqlalchemy.engine import URL
+    connection_url = URL.create(
+        "mssql+pyodbc",
+        username="scott",
+        password="tiger",
+        host="myhost",
+        port=49242,
+        database="databasename",
+        query={
+            "driver": "ODBC Driver 17 for SQL Server",
+            "authentication": "ActiveDirectoryIntegrated",
+        },
+    )
+
+
+Pass through exact Pyodbc string
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+A PyODBC connection string can also be sent in pyodbc's format directly, as
+specified in `the PyODBC documentation
+<https://github.com/mkleehammer/pyodbc/wiki/Connecting-to-databases>`_,
+using the parameter ``odbc_connect``.  A :class:`_sa.engine.URL` object
+can help make this easier::
+
+    from sqlalchemy.engine import URL
+    connection_string = "DRIVER={SQL Server Native Client 10.0};SERVER=dagger;DATABASE=test;UID=user;PWD=password"
+    connection_url = URL.create("mssql+pyodbc", query={"odbc_connect": connection_string})
+
+    engine = create_engine(connection_url)
+
+.. _mssql_pyodbc_access_tokens:
+
+Connecting to databases with access tokens
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Some database servers are set up to only accept access tokens for login. For
+example, SQL Server allows the use of Azure Active Directory tokens to connect
+to databases. This requires creating a credential object using the
+``azure-identity`` library. More information about the authentication step can be
+found in `Microsoft's documentation
+<https://docs.microsoft.com/en-us/azure/developer/python/azure-sdk-authenticate?tabs=bash>`_.
+
+After getting an engine, the credentials need to be sent to ``pyodbc.connect``
+each time a connection is requested. One way to do this is to set up an event
+listener on the engine that adds the credential token to the dialect's connect
+call. This is discussed more generally in :ref:`engines_dynamic_tokens`. For
+SQL Server in particular, this is passed as an ODBC connection attribute with
+a data structure `described by Microsoft
+<https://docs.microsoft.com/en-us/sql/connect/odbc/using-azure-active-directory#authenticating-with-an-access-token>`_.
+
+The following code snippet will create an engine that connects to an Azure SQL
+database using Azure credentials::
+
+    import struct
+    from sqlalchemy import create_engine, event
+    from sqlalchemy.engine.url import URL
+    from azure import identity
+
+    SQL_COPT_SS_ACCESS_TOKEN = 1256  # Connection option for access tokens, as defined in msodbcsql.h
+    TOKEN_URL = "https://database.windows.net/"  # The token URL for any Azure SQL database
+
+    connection_string = "mssql+pyodbc://@my-server.database.windows.net/myDb?driver=ODBC+Driver+17+for+SQL+Server"
+
+    engine = create_engine(connection_string)
+
+    azure_credentials = identity.DefaultAzureCredential()
+
+    @event.listens_for(engine, "do_connect")
+    def provide_token(dialect, conn_rec, cargs, cparams):
+        # remove the "Trusted_Connection" parameter that SQLAlchemy adds
+        cargs[0] = cargs[0].replace(";Trusted_Connection=Yes", "")
+
+        # create token credential
+        raw_token = azure_credentials.get_token(TOKEN_URL).token.encode("utf-16-le")
+        token_struct = struct.pack(f"<I{len(raw_token)}s", len(raw_token), raw_token)
+
+        # apply it to keyword arguments
+        cparams["attrs_before"] = {SQL_COPT_SS_ACCESS_TOKEN: token_struct}
+
+.. tip::
+
+    The ``Trusted_Connection`` token is currently added by the SQLAlchemy
+    pyodbc dialect when no username or password is present.  This needs
+    to be removed per Microsoft's
+    `documentation for Azure access tokens
+    <https://docs.microsoft.com/en-us/sql/connect/odbc/using-azure-active-directory#authenticating-with-an-access-token>`_,
+    stating that a connection string when using an access token must not contain
+    ``UID``, ``PWD``, ``Authentication`` or ``Trusted_Connection`` parameters.
+
+.. _azure_synapse_ignore_no_transaction_on_rollback:
+
+Avoiding transaction-related exceptions on Azure Synapse Analytics
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Azure Synapse Analytics has a significant difference in its transaction
+handling compared to plain SQL Server; in some cases an error within a Synapse
+transaction can cause it to be arbitrarily terminated on the server side, which
+then causes the DBAPI ``.rollback()`` method (as well as ``.commit()``) to
+fail. The issue prevents the usual DBAPI contract of allowing ``.rollback()``
+to pass silently if no transaction is present as the driver does not expect
+this condition. The symptom of this failure is an exception with a message
+resembling 'No corresponding transaction found. (111214)' when attempting to
+emit a ``.rollback()`` after an operation had a failure of some kind.
+
+This specific case can be handled by passing ``ignore_no_transaction_on_rollback=True`` to
+the SQL Server dialect via the :func:`_sa.create_engine` function as follows::
+
+    engine = create_engine(connection_url, ignore_no_transaction_on_rollback=True)
+
+Using the above parameter, the dialect will catch ``ProgrammingError``
+exceptions raised during ``connection.rollback()`` and emit a warning
+if the error message contains code ``111214``, however will not raise
+an exception.
+
+.. versionadded:: 1.4.40  Added the
+   ``ignore_no_transaction_on_rollback=True`` parameter.
+
+Enable autocommit for Azure SQL Data Warehouse (DW) connections
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Azure SQL Data Warehouse does not support transactions,
+and that can cause problems with SQLAlchemy's "autobegin" (and implicit
+commit/rollback) behavior. We can avoid these problems by enabling autocommit
+at both the pyodbc and engine levels::
+
+    connection_url = sa.engine.URL.create(
+        "mssql+pyodbc",
+        username="scott",
+        password="tiger",
+        host="dw.azure.example.com",
+        database="mydb",
+        query={
+            "driver": "ODBC Driver 17 for SQL Server",
+            "autocommit": "True",
+        },
+    )
+
+    engine = create_engine(connection_url).execution_options(
+        isolation_level="AUTOCOMMIT"
+    )
+
+Avoiding sending large string parameters as TEXT/NTEXT
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+By default, for historical reasons, Microsoft's ODBC drivers for SQL Server
+send long string parameters (greater than 4000 SBCS characters or 2000 Unicode
+characters) as TEXT/NTEXT values. TEXT and NTEXT have been deprecated for many
+years and are starting to cause compatibility issues with newer versions of
+SQL_Server/Azure. For example, see `this
+issue <https://github.com/mkleehammer/pyodbc/issues/835>`_.
+
+Starting with ODBC Driver 18 for SQL Server we can override the legacy
+behavior and pass long strings as varchar(max)/nvarchar(max) using the
+``LongAsMax=Yes`` connection string parameter::
+
+    connection_url = sa.engine.URL.create(
+        "mssql+pyodbc",
+        username="scott",
+        password="tiger",
+        host="mssqlserver.example.com",
+        database="mydb",
+        query={
+            "driver": "ODBC Driver 18 for SQL Server",
+            "LongAsMax": "Yes",
+        },
+    )
+
+
+Pyodbc Pooling / connection close behavior
+------------------------------------------
+
+PyODBC uses internal `pooling
+<https://github.com/mkleehammer/pyodbc/wiki/The-pyodbc-Module#pooling>`_ by
+default, which means connections will be longer lived than they are within
+SQLAlchemy itself.  As SQLAlchemy has its own pooling behavior, it is often
+preferable to disable this behavior.  This behavior can only be disabled
+globally at the PyODBC module level, **before** any connections are made::
+
+    import pyodbc
+
+    pyodbc.pooling = False
+
+    # don't use the engine before pooling is set to False
+    engine = create_engine("mssql+pyodbc://user:pass@dsn")
+
+If this variable is left at its default value of ``True``, **the application
+will continue to maintain active database connections**, even when the
+SQLAlchemy engine itself fully discards a connection or if the engine is
+disposed.
+
+.. seealso::
+
+    `pooling <https://github.com/mkleehammer/pyodbc/wiki/The-pyodbc-Module#pooling>`_ -
+    in the PyODBC documentation.
+
+Driver / Unicode Support
+-------------------------
+
+PyODBC works best with Microsoft ODBC drivers, particularly in the area
+of Unicode support on both Python 2 and Python 3.
+
+Using the FreeTDS ODBC drivers on Linux or OSX with PyODBC is **not**
+recommended; there have been historically many Unicode-related issues
+in this area, including before Microsoft offered ODBC drivers for Linux
+and OSX.   Now that Microsoft offers drivers for all platforms, for
+PyODBC support these are recommended.  FreeTDS remains relevant for
+non-ODBC drivers such as pymssql where it works very well.
+
+
+Rowcount Support
+----------------
+
+Pyodbc only has partial support for rowcount.  See the notes at
+:ref:`mssql_rowcount_versioning` for important notes when using ORM
+versioning.
+
+.. _mssql_pyodbc_fastexecutemany:
+
+Fast Executemany Mode
+---------------------
+
+The Pyodbc driver has added support for a "fast executemany" mode of execution
+which greatly reduces round trips for a DBAPI ``executemany()`` call when using
+Microsoft ODBC drivers, for **limited size batches that fit in memory**.  The
+feature is enabled by setting the flag ``.fast_executemany`` on the DBAPI
+cursor when an executemany call is to be used.   The SQLAlchemy pyodbc SQL
+Server dialect supports setting this flag automatically when the
+``.fast_executemany`` flag is passed to
+:func:`_sa.create_engine` ; note that the ODBC driver must be the Microsoft
+driver in order to use this flag::
+
+    engine = create_engine(
+        "mssql+pyodbc://scott:tiger@mssql2017:1433/test?driver=ODBC+Driver+13+for+SQL+Server",
+        fast_executemany=True)
+
+.. warning:: The pyodbc fast_executemany mode **buffers all rows in memory** and is
+   not compatible with very large batches of data.    A future version of SQLAlchemy
+   may support this flag as a per-execution option instead.
+
+.. versionadded:: 1.3
+
+.. seealso::
+
+    `fast executemany <https://github.com/mkleehammer/pyodbc/wiki/Features-beyond-the-DB-API#fast_executemany>`_
+    - on github
+
+.. _mssql_pyodbc_setinputsizes:
+
+Setinputsizes Support
+-----------------------
+
+The pyodbc ``cursor.setinputsizes()`` method can be used if necessary.  To
+enable this hook, pass ``use_setinputsizes=True`` to :func:`_sa.create_engine`::
+
+    engine = create_engine("mssql+pyodbc://...", use_setinputsizes=True)
+
+The behavior of the hook can then be customized, as may be necessary
+particularly if fast_executemany is in use, via the
+:meth:`.DialectEvents.do_setinputsizes` hook. See that method for usage
+examples.
+
+.. versionchanged:: 1.4.1  The pyodbc dialects will not use setinputsizes
+   unless ``use_setinputsizes=True`` is passed.
+
+"""  # noqa
+
+
+import datetime
+import decimal
+import re
+import struct
+
+from .base import BINARY
+from .base import DATETIMEOFFSET
+from .base import MSDialect
+from .base import MSExecutionContext
+from .base import VARBINARY
+from ... import exc
+from ... import types as sqltypes
+from ... import util
+from ...connectors.pyodbc import PyODBCConnector
+
+
+class _ms_numeric_pyodbc(object):
+
+    """Turns Decimals with adjusted() < 0 or > 7 into strings.
+
+    The routines here are needed for older pyodbc versions
+    as well as current mxODBC versions.
+
+    """
+
+    def bind_processor(self, dialect):
+
+        super_process = super(_ms_numeric_pyodbc, self).bind_processor(dialect)
+
+        if not dialect._need_decimal_fix:
+            return super_process
+
+        def process(value):
+            if self.asdecimal and isinstance(value, decimal.Decimal):
+                adjusted = value.adjusted()
+                if adjusted < 0:
+                    return self._small_dec_to_string(value)
+                elif adjusted > 7:
+                    return self._large_dec_to_string(value)
+
+            if super_process:
+                return super_process(value)
+            else:
+                return value
+
+        return process
+
+    # these routines needed for older versions of pyodbc.
+    # as of 2.1.8 this logic is integrated.
+
+    def _small_dec_to_string(self, value):
+        return "%s0.%s%s" % (
+            (value < 0 and "-" or ""),
+            "0" * (abs(value.adjusted()) - 1),
+            "".join([str(nint) for nint in value.as_tuple()[1]]),
+        )
+
+    def _large_dec_to_string(self, value):
+        _int = value.as_tuple()[1]
+        if "E" in str(value):
+            result = "%s%s%s" % (
+                (value < 0 and "-" or ""),
+                "".join([str(s) for s in _int]),
+                "0" * (value.adjusted() - (len(_int) - 1)),
+            )
+        else:
+            if (len(_int) - 1) > value.adjusted():
+                result = "%s%s.%s" % (
+                    (value < 0 and "-" or ""),
+                    "".join([str(s) for s in _int][0 : value.adjusted() + 1]),
+                    "".join([str(s) for s in _int][value.adjusted() + 1 :]),
+                )
+            else:
+                result = "%s%s" % (
+                    (value < 0 and "-" or ""),
+                    "".join([str(s) for s in _int][0 : value.adjusted() + 1]),
+                )
+        return result
+
+
+class _MSNumeric_pyodbc(_ms_numeric_pyodbc, sqltypes.Numeric):
+    pass
+
+
+class _MSFloat_pyodbc(_ms_numeric_pyodbc, sqltypes.Float):
+    pass
+
+
+class _ms_binary_pyodbc(object):
+    """Wraps binary values in dialect-specific Binary wrapper.
+    If the value is null, return a pyodbc-specific BinaryNull
+    object to prevent pyODBC [and FreeTDS] from defaulting binary
+    NULL types to SQLWCHAR and causing implicit conversion errors.
+    """
+
+    def bind_processor(self, dialect):
+        if dialect.dbapi is None:
+            return None
+
+        DBAPIBinary = dialect.dbapi.Binary
+
+        def process(value):
+            if value is not None:
+                return DBAPIBinary(value)
+            else:
+                # pyodbc-specific
+                return dialect.dbapi.BinaryNull
+
+        return process
+
+
+class _ODBCDateTimeBindProcessor(object):
+    """Add bind processors to handle datetimeoffset behaviors"""
+
+    has_tz = False
+
+    def bind_processor(self, dialect):
+        def process(value):
+            if value is None:
+                return None
+            elif isinstance(value, util.string_types):
+                # if a string was passed directly, allow it through
+                return value
+            elif not value.tzinfo or (not self.timezone and not self.has_tz):
+                # for DateTime(timezone=False)
+                return value
+            else:
+                # for DATETIMEOFFSET or DateTime(timezone=True)
+                #
+                # Convert to string format required by T-SQL
+                dto_string = value.strftime("%Y-%m-%d %H:%M:%S.%f %z")
+                # offset needs a colon, e.g., -0700 -> -07:00
+                # "UTC offset in the form (+-)HHMM[SS[.ffffff]]"
+                # backend currently rejects seconds / fractional seconds
+                dto_string = re.sub(
+                    r"([\+\-]\d{2})([\d\.]+)$", r"\1:\2", dto_string
+                )
+                return dto_string
+
+        return process
+
+
+class _ODBCDateTime(_ODBCDateTimeBindProcessor, sqltypes.DateTime):
+    pass
+
+
+class _ODBCDATETIMEOFFSET(_ODBCDateTimeBindProcessor, DATETIMEOFFSET):
+    has_tz = True
+
+
+class _VARBINARY_pyodbc(_ms_binary_pyodbc, VARBINARY):
+    pass
+
+
+class _BINARY_pyodbc(_ms_binary_pyodbc, BINARY):
+    pass
+
+
+class MSExecutionContext_pyodbc(MSExecutionContext):
+    _embedded_scope_identity = False
+
+    def pre_exec(self):
+        """where appropriate, issue "select scope_identity()" in the same
+        statement.
+
+        Background on why "scope_identity()" is preferable to "@@identity":
+        https://msdn.microsoft.com/en-us/library/ms190315.aspx
+
+        Background on why we attempt to embed "scope_identity()" into the same
+        statement as the INSERT:
+        https://code.google.com/p/pyodbc/wiki/FAQs#How_do_I_retrieve_autogenerated/identity_values?
+
+        """
+
+        super(MSExecutionContext_pyodbc, self).pre_exec()
+
+        # don't embed the scope_identity select into an
+        # "INSERT .. DEFAULT VALUES"
+        if (
+            self._select_lastrowid
+            and self.dialect.use_scope_identity
+            and len(self.parameters[0])
+        ):
+            self._embedded_scope_identity = True
+
+            self.statement += "; select scope_identity()"
+
+    def post_exec(self):
+        if self._embedded_scope_identity:
+            # Fetch the last inserted id from the manipulated statement
+            # We may have to skip over a number of result sets with
+            # no data (due to triggers, etc.)
+            while True:
+                try:
+                    # fetchall() ensures the cursor is consumed
+                    # without closing it (FreeTDS particularly)
+                    row = self.cursor.fetchall()[0]
+                    break
+                except self.dialect.dbapi.Error:
+                    # no way around this - nextset() consumes the previous set
+                    # so we need to just keep flipping
+                    self.cursor.nextset()
+
+            self._lastrowid = int(row[0])
+        else:
+            super(MSExecutionContext_pyodbc, self).post_exec()
+
+
+class MSDialect_pyodbc(PyODBCConnector, MSDialect):
+    supports_statement_cache = True
+
+    # mssql still has problems with this on Linux
+    supports_sane_rowcount_returning = False
+
+    execution_ctx_cls = MSExecutionContext_pyodbc
+
+    colspecs = util.update_copy(
+        MSDialect.colspecs,
+        {
+            sqltypes.Numeric: _MSNumeric_pyodbc,
+            sqltypes.Float: _MSFloat_pyodbc,
+            BINARY: _BINARY_pyodbc,
+            # support DateTime(timezone=True)
+            sqltypes.DateTime: _ODBCDateTime,
+            DATETIMEOFFSET: _ODBCDATETIMEOFFSET,
+            # SQL Server dialect has a VARBINARY that is just to support
+            # "deprecate_large_types" w/ VARBINARY(max), but also we must
+            # handle the usual SQL standard VARBINARY
+            VARBINARY: _VARBINARY_pyodbc,
+            sqltypes.VARBINARY: _VARBINARY_pyodbc,
+            sqltypes.LargeBinary: _VARBINARY_pyodbc,
+        },
+    )
+
+    def __init__(
+        self, description_encoding=None, fast_executemany=False, **params
+    ):
+        if "description_encoding" in params:
+            self.description_encoding = params.pop("description_encoding")
+        super(MSDialect_pyodbc, self).__init__(**params)
+        self.use_scope_identity = (
+            self.use_scope_identity
+            and self.dbapi
+            and hasattr(self.dbapi.Cursor, "nextset")
+        )
+        self._need_decimal_fix = self.dbapi and self._dbapi_version() < (
+            2,
+            1,
+            8,
+        )
+        self.fast_executemany = fast_executemany
+
+    def _get_server_version_info(self, connection):
+        try:
+            # "Version of the instance of SQL Server, in the form
+            # of 'major.minor.build.revision'"
+            raw = connection.exec_driver_sql(
+                "SELECT CAST(SERVERPROPERTY('ProductVersion') AS VARCHAR)"
+            ).scalar()
+        except exc.DBAPIError:
+            # SQL Server docs indicate this function isn't present prior to
+            # 2008.  Before we had the VARCHAR cast above, pyodbc would also
+            # fail on this query.
+            return super(MSDialect_pyodbc, self)._get_server_version_info(
+                connection, allow_chars=False
+            )
+        else:
+            version = []
+            r = re.compile(r"[.\-]")
+            for n in r.split(raw):
+                try:
+                    version.append(int(n))
+                except ValueError:
+                    pass
+            return tuple(version)
+
+    def on_connect(self):
+        super_ = super(MSDialect_pyodbc, self).on_connect()
+
+        def on_connect(conn):
+            if super_ is not None:
+                super_(conn)
+
+            self._setup_timestampoffset_type(conn)
+
+        return on_connect
+
+    def _setup_timestampoffset_type(self, connection):
+        # output converter function for datetimeoffset
+        def _handle_datetimeoffset(dto_value):
+            tup = struct.unpack("<6hI2h", dto_value)
+            return datetime.datetime(
+                tup[0],
+                tup[1],
+                tup[2],
+                tup[3],
+                tup[4],
+                tup[5],
+                tup[6] // 1000,
+                util.timezone(
+                    datetime.timedelta(hours=tup[7], minutes=tup[8])
+                ),
+            )
+
+        odbc_SQL_SS_TIMESTAMPOFFSET = -155  # as defined in SQLNCLI.h
+        connection.add_output_converter(
+            odbc_SQL_SS_TIMESTAMPOFFSET, _handle_datetimeoffset
+        )
+
+    def do_executemany(self, cursor, statement, parameters, context=None):
+        if self.fast_executemany:
+            cursor.fast_executemany = True
+        super(MSDialect_pyodbc, self).do_executemany(
+            cursor, statement, parameters, context=context
+        )
+
+    def is_disconnect(self, e, connection, cursor):
+        if isinstance(e, self.dbapi.Error):
+            code = e.args[0]
+            if code in {
+                "08S01",
+                "01000",
+                "01002",
+                "08003",
+                "08007",
+                "08S02",
+                "08001",
+                "HYT00",
+                "HY010",
+                "10054",
+            }:
+                return True
+        return super(MSDialect_pyodbc, self).is_disconnect(
+            e, connection, cursor
+        )
+
+
+dialect = MSDialect_pyodbc

lib/sqlalchemy/dialects/mysql/__init__.py

@@ -0,0 +1,103 @@
+# mysql/__init__.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from . import base  # noqa
+from . import cymysql  # noqa
+from . import mariadbconnector  # noqa
+from . import mysqlconnector  # noqa
+from . import mysqldb  # noqa
+from . import oursql  # noqa
+from . import pymysql  # noqa
+from . import pyodbc  # noqa
+from .base import BIGINT
+from .base import BINARY
+from .base import BIT
+from .base import BLOB
+from .base import BOOLEAN
+from .base import CHAR
+from .base import DATE
+from .base import DATETIME
+from .base import DECIMAL
+from .base import DOUBLE
+from .base import ENUM
+from .base import FLOAT
+from .base import INTEGER
+from .base import JSON
+from .base import LONGBLOB
+from .base import LONGTEXT
+from .base import MEDIUMBLOB
+from .base import MEDIUMINT
+from .base import MEDIUMTEXT
+from .base import NCHAR
+from .base import NUMERIC
+from .base import NVARCHAR
+from .base import REAL
+from .base import SET
+from .base import SMALLINT
+from .base import TEXT
+from .base import TIME
+from .base import TIMESTAMP
+from .base import TINYBLOB
+from .base import TINYINT
+from .base import TINYTEXT
+from .base import VARBINARY
+from .base import VARCHAR
+from .base import YEAR
+from .dml import Insert
+from .dml import insert
+from .expression import match
+from ...util import compat
+
+if compat.py3k:
+    from . import aiomysql  # noqa
+    from . import asyncmy  # noqa
+
+# default dialect
+base.dialect = dialect = mysqldb.dialect
+
+__all__ = (
+    "BIGINT",
+    "BINARY",
+    "BIT",
+    "BLOB",
+    "BOOLEAN",
+    "CHAR",
+    "DATE",
+    "DATETIME",
+    "DECIMAL",
+    "DOUBLE",
+    "ENUM",
+    "DECIMAL",
+    "FLOAT",
+    "INTEGER",
+    "INTEGER",
+    "JSON",
+    "LONGBLOB",
+    "LONGTEXT",
+    "MEDIUMBLOB",
+    "MEDIUMINT",
+    "MEDIUMTEXT",
+    "NCHAR",
+    "NVARCHAR",
+    "NUMERIC",
+    "SET",
+    "SMALLINT",
+    "REAL",
+    "TEXT",
+    "TIME",
+    "TIMESTAMP",
+    "TINYBLOB",
+    "TINYINT",
+    "TINYTEXT",
+    "VARBINARY",
+    "VARCHAR",
+    "YEAR",
+    "dialect",
+    "insert",
+    "Insert",
+    "match",
+)

lib/sqlalchemy/dialects/mysql/aiomysql.py

@@ -0,0 +1,317 @@
+# mysql/aiomysql.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors <see AUTHORS
+# file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+r"""
+.. dialect:: mysql+aiomysql
+    :name: aiomysql
+    :dbapi: aiomysql
+    :connectstring: mysql+aiomysql://user:password@host:port/dbname[?key=value&key=value...]
+    :url: https://github.com/aio-libs/aiomysql
+
+.. warning:: The aiomysql dialect is not currently tested as part of
+   SQLAlchemy’s continuous integration. As of September, 2021 the driver
+   appears to be unmaintained and no longer functions for Python version 3.10,
+   and additionally depends on a significantly outdated version of PyMySQL.
+   Please refer to the :ref:`asyncmy` dialect for current MySQL/MariaDB asyncio
+   functionality.
+
+The aiomysql dialect is SQLAlchemy's second Python asyncio dialect.
+
+Using a special asyncio mediation layer, the aiomysql dialect is usable
+as the backend for the :ref:`SQLAlchemy asyncio <asyncio_toplevel>`
+extension package.
+
+This dialect should normally be used only with the
+:func:`_asyncio.create_async_engine` engine creation function::
+
+    from sqlalchemy.ext.asyncio import create_async_engine
+    engine = create_async_engine("mysql+aiomysql://user:pass@hostname/dbname?charset=utf8mb4")
+
+
+"""  # noqa
+
+from .pymysql import MySQLDialect_pymysql
+from ... import pool
+from ... import util
+from ...engine import AdaptedConnection
+from ...util.concurrency import asyncio
+from ...util.concurrency import await_fallback
+from ...util.concurrency import await_only
+
+
+class AsyncAdapt_aiomysql_cursor:
+    server_side = False
+    __slots__ = (
+        "_adapt_connection",
+        "_connection",
+        "await_",
+        "_cursor",
+        "_rows",
+    )
+
+    def __init__(self, adapt_connection):
+        self._adapt_connection = adapt_connection
+        self._connection = adapt_connection._connection
+        self.await_ = adapt_connection.await_
+
+        cursor = self._connection.cursor()
+
+        # see https://github.com/aio-libs/aiomysql/issues/543
+        self._cursor = self.await_(cursor.__aenter__())
+        self._rows = []
+
+    @property
+    def description(self):
+        return self._cursor.description
+
+    @property
+    def rowcount(self):
+        return self._cursor.rowcount
+
+    @property
+    def arraysize(self):
+        return self._cursor.arraysize
+
+    @arraysize.setter
+    def arraysize(self, value):
+        self._cursor.arraysize = value
+
+    @property
+    def lastrowid(self):
+        return self._cursor.lastrowid
+
+    def close(self):
+        # note we aren't actually closing the cursor here,
+        # we are just letting GC do it.   to allow this to be async
+        # we would need the Result to change how it does "Safe close cursor".
+        # MySQL "cursors" don't actually have state to be "closed" besides
+        # exhausting rows, which we already have done for sync cursor.
+        # another option would be to emulate aiosqlite dialect and assign
+        # cursor only if we are doing server side cursor operation.
+        self._rows[:] = []
+
+    def execute(self, operation, parameters=None):
+        return self.await_(self._execute_async(operation, parameters))
+
+    def executemany(self, operation, seq_of_parameters):
+        return self.await_(
+            self._executemany_async(operation, seq_of_parameters)
+        )
+
+    async def _execute_async(self, operation, parameters):
+        async with self._adapt_connection._execute_mutex:
+            if parameters is None:
+                result = await self._cursor.execute(operation)
+            else:
+                result = await self._cursor.execute(operation, parameters)
+
+            if not self.server_side:
+                # aiomysql has a "fake" async result, so we have to pull it out
+                # of that here since our default result is not async.
+                # we could just as easily grab "_rows" here and be done with it
+                # but this is safer.
+                self._rows = list(await self._cursor.fetchall())
+            return result
+
+    async def _executemany_async(self, operation, seq_of_parameters):
+        async with self._adapt_connection._execute_mutex:
+            return await self._cursor.executemany(operation, seq_of_parameters)
+
+    def setinputsizes(self, *inputsizes):
+        pass
+
+    def __iter__(self):
+        while self._rows:
+            yield self._rows.pop(0)
+
+    def fetchone(self):
+        if self._rows:
+            return self._rows.pop(0)
+        else:
+            return None
+
+    def fetchmany(self, size=None):
+        if size is None:
+            size = self.arraysize
+
+        retval = self._rows[0:size]
+        self._rows[:] = self._rows[size:]
+        return retval
+
+    def fetchall(self):
+        retval = self._rows[:]
+        self._rows[:] = []
+        return retval
+
+
+class AsyncAdapt_aiomysql_ss_cursor(AsyncAdapt_aiomysql_cursor):
+    __slots__ = ()
+    server_side = True
+
+    def __init__(self, adapt_connection):
+        self._adapt_connection = adapt_connection
+        self._connection = adapt_connection._connection
+        self.await_ = adapt_connection.await_
+
+        cursor = self._connection.cursor(
+            adapt_connection.dbapi.aiomysql.SSCursor
+        )
+
+        self._cursor = self.await_(cursor.__aenter__())
+
+    def close(self):
+        if self._cursor is not None:
+            self.await_(self._cursor.close())
+            self._cursor = None
+
+    def fetchone(self):
+        return self.await_(self._cursor.fetchone())
+
+    def fetchmany(self, size=None):
+        return self.await_(self._cursor.fetchmany(size=size))
+
+    def fetchall(self):
+        return self.await_(self._cursor.fetchall())
+
+
+class AsyncAdapt_aiomysql_connection(AdaptedConnection):
+    await_ = staticmethod(await_only)
+    __slots__ = ("dbapi", "_connection", "_execute_mutex")
+
+    def __init__(self, dbapi, connection):
+        self.dbapi = dbapi
+        self._connection = connection
+        self._execute_mutex = asyncio.Lock()
+
+    def ping(self, reconnect):
+        return self.await_(self._connection.ping(reconnect))
+
+    def character_set_name(self):
+        return self._connection.character_set_name()
+
+    def autocommit(self, value):
+        self.await_(self._connection.autocommit(value))
+
+    def cursor(self, server_side=False):
+        if server_side:
+            return AsyncAdapt_aiomysql_ss_cursor(self)
+        else:
+            return AsyncAdapt_aiomysql_cursor(self)
+
+    def rollback(self):
+        self.await_(self._connection.rollback())
+
+    def commit(self):
+        self.await_(self._connection.commit())
+
+    def close(self):
+        # it's not awaitable.
+        self._connection.close()
+
+
+class AsyncAdaptFallback_aiomysql_connection(AsyncAdapt_aiomysql_connection):
+    __slots__ = ()
+
+    await_ = staticmethod(await_fallback)
+
+
+class AsyncAdapt_aiomysql_dbapi:
+    def __init__(self, aiomysql, pymysql):
+        self.aiomysql = aiomysql
+        self.pymysql = pymysql
+        self.paramstyle = "format"
+        self._init_dbapi_attributes()
+
+    def _init_dbapi_attributes(self):
+        for name in (
+            "Warning",
+            "Error",
+            "InterfaceError",
+            "DataError",
+            "DatabaseError",
+            "OperationalError",
+            "InterfaceError",
+            "IntegrityError",
+            "ProgrammingError",
+            "InternalError",
+            "NotSupportedError",
+        ):
+            setattr(self, name, getattr(self.aiomysql, name))
+
+        for name in (
+            "NUMBER",
+            "STRING",
+            "DATETIME",
+            "BINARY",
+            "TIMESTAMP",
+            "Binary",
+        ):
+            setattr(self, name, getattr(self.pymysql, name))
+
+    def connect(self, *arg, **kw):
+        async_fallback = kw.pop("async_fallback", False)
+
+        if util.asbool(async_fallback):
+            return AsyncAdaptFallback_aiomysql_connection(
+                self,
+                await_fallback(self.aiomysql.connect(*arg, **kw)),
+            )
+        else:
+            return AsyncAdapt_aiomysql_connection(
+                self,
+                await_only(self.aiomysql.connect(*arg, **kw)),
+            )
+
+
+class MySQLDialect_aiomysql(MySQLDialect_pymysql):
+    driver = "aiomysql"
+    supports_statement_cache = True
+
+    supports_server_side_cursors = True
+    _sscursor = AsyncAdapt_aiomysql_ss_cursor
+
+    is_async = True
+
+    @classmethod
+    def dbapi(cls):
+        return AsyncAdapt_aiomysql_dbapi(
+            __import__("aiomysql"), __import__("pymysql")
+        )
+
+    @classmethod
+    def get_pool_class(cls, url):
+
+        async_fallback = url.query.get("async_fallback", False)
+
+        if util.asbool(async_fallback):
+            return pool.FallbackAsyncAdaptedQueuePool
+        else:
+            return pool.AsyncAdaptedQueuePool
+
+    def create_connect_args(self, url):
+        return super(MySQLDialect_aiomysql, self).create_connect_args(
+            url, _translate_args=dict(username="user", database="db")
+        )
+
+    def is_disconnect(self, e, connection, cursor):
+        if super(MySQLDialect_aiomysql, self).is_disconnect(
+            e, connection, cursor
+        ):
+            return True
+        else:
+            str_e = str(e).lower()
+            return "not connected" in str_e
+
+    def _found_rows_client_flag(self):
+        from pymysql.constants import CLIENT
+
+        return CLIENT.FOUND_ROWS
+
+    def get_driver_connection(self, connection):
+        return connection._connection
+
+
+dialect = MySQLDialect_aiomysql

lib/sqlalchemy/dialects/mysql/asyncmy.py

@@ -0,0 +1,328 @@
+# mysql/asyncmy.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors <see AUTHORS
+# file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+r"""
+.. dialect:: mysql+asyncmy
+    :name: asyncmy
+    :dbapi: asyncmy
+    :connectstring: mysql+asyncmy://user:password@host:port/dbname[?key=value&key=value...]
+    :url: https://github.com/long2ice/asyncmy
+
+.. note:: The asyncmy dialect as of September, 2021 was added to provide
+   MySQL/MariaDB asyncio compatibility given that the :ref:`aiomysql` database
+   driver has become unmaintained, however asyncmy is itself very new.
+
+Using a special asyncio mediation layer, the asyncmy dialect is usable
+as the backend for the :ref:`SQLAlchemy asyncio <asyncio_toplevel>`
+extension package.
+
+This dialect should normally be used only with the
+:func:`_asyncio.create_async_engine` engine creation function::
+
+    from sqlalchemy.ext.asyncio import create_async_engine
+    engine = create_async_engine("mysql+asyncmy://user:pass@hostname/dbname?charset=utf8mb4")
+
+
+"""  # noqa
+
+from .pymysql import MySQLDialect_pymysql
+from ... import pool
+from ... import util
+from ...engine import AdaptedConnection
+from ...util.concurrency import asynccontextmanager
+from ...util.concurrency import asyncio
+from ...util.concurrency import await_fallback
+from ...util.concurrency import await_only
+
+
+class AsyncAdapt_asyncmy_cursor:
+    server_side = False
+    __slots__ = (
+        "_adapt_connection",
+        "_connection",
+        "await_",
+        "_cursor",
+        "_rows",
+    )
+
+    def __init__(self, adapt_connection):
+        self._adapt_connection = adapt_connection
+        self._connection = adapt_connection._connection
+        self.await_ = adapt_connection.await_
+
+        cursor = self._connection.cursor()
+
+        self._cursor = self.await_(cursor.__aenter__())
+        self._rows = []
+
+    @property
+    def description(self):
+        return self._cursor.description
+
+    @property
+    def rowcount(self):
+        return self._cursor.rowcount
+
+    @property
+    def arraysize(self):
+        return self._cursor.arraysize
+
+    @arraysize.setter
+    def arraysize(self, value):
+        self._cursor.arraysize = value
+
+    @property
+    def lastrowid(self):
+        return self._cursor.lastrowid
+
+    def close(self):
+        # note we aren't actually closing the cursor here,
+        # we are just letting GC do it.   to allow this to be async
+        # we would need the Result to change how it does "Safe close cursor".
+        # MySQL "cursors" don't actually have state to be "closed" besides
+        # exhausting rows, which we already have done for sync cursor.
+        # another option would be to emulate aiosqlite dialect and assign
+        # cursor only if we are doing server side cursor operation.
+        self._rows[:] = []
+
+    def execute(self, operation, parameters=None):
+        return self.await_(self._execute_async(operation, parameters))
+
+    def executemany(self, operation, seq_of_parameters):
+        return self.await_(
+            self._executemany_async(operation, seq_of_parameters)
+        )
+
+    async def _execute_async(self, operation, parameters):
+        async with self._adapt_connection._mutex_and_adapt_errors():
+            if parameters is None:
+                result = await self._cursor.execute(operation)
+            else:
+                result = await self._cursor.execute(operation, parameters)
+
+            if not self.server_side:
+                # asyncmy has a "fake" async result, so we have to pull it out
+                # of that here since our default result is not async.
+                # we could just as easily grab "_rows" here and be done with it
+                # but this is safer.
+                self._rows = list(await self._cursor.fetchall())
+            return result
+
+    async def _executemany_async(self, operation, seq_of_parameters):
+        async with self._adapt_connection._mutex_and_adapt_errors():
+            return await self._cursor.executemany(operation, seq_of_parameters)
+
+    def setinputsizes(self, *inputsizes):
+        pass
+
+    def __iter__(self):
+        while self._rows:
+            yield self._rows.pop(0)
+
+    def fetchone(self):
+        if self._rows:
+            return self._rows.pop(0)
+        else:
+            return None
+
+    def fetchmany(self, size=None):
+        if size is None:
+            size = self.arraysize
+
+        retval = self._rows[0:size]
+        self._rows[:] = self._rows[size:]
+        return retval
+
+    def fetchall(self):
+        retval = self._rows[:]
+        self._rows[:] = []
+        return retval
+
+
+class AsyncAdapt_asyncmy_ss_cursor(AsyncAdapt_asyncmy_cursor):
+    __slots__ = ()
+    server_side = True
+
+    def __init__(self, adapt_connection):
+        self._adapt_connection = adapt_connection
+        self._connection = adapt_connection._connection
+        self.await_ = adapt_connection.await_
+
+        cursor = self._connection.cursor(
+            adapt_connection.dbapi.asyncmy.cursors.SSCursor
+        )
+
+        self._cursor = self.await_(cursor.__aenter__())
+
+    def close(self):
+        if self._cursor is not None:
+            self.await_(self._cursor.close())
+            self._cursor = None
+
+    def fetchone(self):
+        return self.await_(self._cursor.fetchone())
+
+    def fetchmany(self, size=None):
+        return self.await_(self._cursor.fetchmany(size=size))
+
+    def fetchall(self):
+        return self.await_(self._cursor.fetchall())
+
+
+class AsyncAdapt_asyncmy_connection(AdaptedConnection):
+    await_ = staticmethod(await_only)
+    __slots__ = ("dbapi", "_connection", "_execute_mutex")
+
+    def __init__(self, dbapi, connection):
+        self.dbapi = dbapi
+        self._connection = connection
+        self._execute_mutex = asyncio.Lock()
+
+    @asynccontextmanager
+    async def _mutex_and_adapt_errors(self):
+        async with self._execute_mutex:
+            try:
+                yield
+            except AttributeError:
+                raise self.dbapi.InternalError(
+                    "network operation failed due to asyncmy attribute error"
+                )
+
+    def ping(self, reconnect):
+        assert not reconnect
+        return self.await_(self._do_ping())
+
+    async def _do_ping(self):
+        async with self._mutex_and_adapt_errors():
+            return await self._connection.ping(False)
+
+    def character_set_name(self):
+        return self._connection.character_set_name()
+
+    def autocommit(self, value):
+        self.await_(self._connection.autocommit(value))
+
+    def cursor(self, server_side=False):
+        if server_side:
+            return AsyncAdapt_asyncmy_ss_cursor(self)
+        else:
+            return AsyncAdapt_asyncmy_cursor(self)
+
+    def rollback(self):
+        self.await_(self._connection.rollback())
+
+    def commit(self):
+        self.await_(self._connection.commit())
+
+    def close(self):
+        # it's not awaitable.
+        self._connection.close()
+
+
+class AsyncAdaptFallback_asyncmy_connection(AsyncAdapt_asyncmy_connection):
+    __slots__ = ()
+
+    await_ = staticmethod(await_fallback)
+
+
+def _Binary(x):
+    """Return x as a binary type."""
+    return bytes(x)
+
+
+class AsyncAdapt_asyncmy_dbapi:
+    def __init__(self, asyncmy):
+        self.asyncmy = asyncmy
+        self.paramstyle = "format"
+        self._init_dbapi_attributes()
+
+    def _init_dbapi_attributes(self):
+        for name in (
+            "Warning",
+            "Error",
+            "InterfaceError",
+            "DataError",
+            "DatabaseError",
+            "OperationalError",
+            "InterfaceError",
+            "IntegrityError",
+            "ProgrammingError",
+            "InternalError",
+            "NotSupportedError",
+        ):
+            setattr(self, name, getattr(self.asyncmy.errors, name))
+
+    STRING = util.symbol("STRING")
+    NUMBER = util.symbol("NUMBER")
+    BINARY = util.symbol("BINARY")
+    DATETIME = util.symbol("DATETIME")
+    TIMESTAMP = util.symbol("TIMESTAMP")
+    Binary = staticmethod(_Binary)
+
+    def connect(self, *arg, **kw):
+        async_fallback = kw.pop("async_fallback", False)
+
+        if util.asbool(async_fallback):
+            return AsyncAdaptFallback_asyncmy_connection(
+                self,
+                await_fallback(self.asyncmy.connect(*arg, **kw)),
+            )
+        else:
+            return AsyncAdapt_asyncmy_connection(
+                self,
+                await_only(self.asyncmy.connect(*arg, **kw)),
+            )
+
+
+class MySQLDialect_asyncmy(MySQLDialect_pymysql):
+    driver = "asyncmy"
+    supports_statement_cache = True
+
+    supports_server_side_cursors = True
+    _sscursor = AsyncAdapt_asyncmy_ss_cursor
+
+    is_async = True
+
+    @classmethod
+    def dbapi(cls):
+        return AsyncAdapt_asyncmy_dbapi(__import__("asyncmy"))
+
+    @classmethod
+    def get_pool_class(cls, url):
+
+        async_fallback = url.query.get("async_fallback", False)
+
+        if util.asbool(async_fallback):
+            return pool.FallbackAsyncAdaptedQueuePool
+        else:
+            return pool.AsyncAdaptedQueuePool
+
+    def create_connect_args(self, url):
+        return super(MySQLDialect_asyncmy, self).create_connect_args(
+            url, _translate_args=dict(username="user", database="db")
+        )
+
+    def is_disconnect(self, e, connection, cursor):
+        if super(MySQLDialect_asyncmy, self).is_disconnect(
+            e, connection, cursor
+        ):
+            return True
+        else:
+            str_e = str(e).lower()
+            return (
+                "not connected" in str_e or "network operation failed" in str_e
+            )
+
+    def _found_rows_client_flag(self):
+        from asyncmy.constants import CLIENT
+
+        return CLIENT.FOUND_ROWS
+
+    def get_driver_connection(self, connection):
+        return connection._connection
+
+
+dialect = MySQLDialect_asyncmy

lib/sqlalchemy/dialects/mysql/cymysql.py

@@ -0,0 +1,82 @@
+# mysql/cymysql.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+r"""
+
+.. dialect:: mysql+cymysql
+    :name: CyMySQL
+    :dbapi: cymysql
+    :connectstring: mysql+cymysql://<username>:<password>@<host>/<dbname>[?<options>]
+    :url: https://github.com/nakagami/CyMySQL
+
+.. note::
+
+    The CyMySQL dialect is **not tested as part of SQLAlchemy's continuous
+    integration** and may have unresolved issues.  The recommended MySQL
+    dialects are mysqlclient and PyMySQL.
+
+"""  # noqa
+
+from .base import BIT
+from .base import MySQLDialect
+from .mysqldb import MySQLDialect_mysqldb
+from ... import util
+
+
+class _cymysqlBIT(BIT):
+    def result_processor(self, dialect, coltype):
+        """Convert MySQL's 64 bit, variable length binary string to a long."""
+
+        def process(value):
+            if value is not None:
+                v = 0
+                for i in util.iterbytes(value):
+                    v = v << 8 | i
+                return v
+            return value
+
+        return process
+
+
+class MySQLDialect_cymysql(MySQLDialect_mysqldb):
+    driver = "cymysql"
+    supports_statement_cache = True
+
+    description_encoding = None
+    supports_sane_rowcount = True
+    supports_sane_multi_rowcount = False
+    supports_unicode_statements = True
+
+    colspecs = util.update_copy(MySQLDialect.colspecs, {BIT: _cymysqlBIT})
+
+    @classmethod
+    def dbapi(cls):
+        return __import__("cymysql")
+
+    def _detect_charset(self, connection):
+        return connection.connection.charset
+
+    def _extract_error_code(self, exception):
+        return exception.errno
+
+    def is_disconnect(self, e, connection, cursor):
+        if isinstance(e, self.dbapi.OperationalError):
+            return self._extract_error_code(e) in (
+                2006,
+                2013,
+                2014,
+                2045,
+                2055,
+            )
+        elif isinstance(e, self.dbapi.InterfaceError):
+            # if underlying connection is closed,
+            # this is the error you get
+            return True
+        else:
+            return False
+
+
+dialect = MySQLDialect_cymysql

lib/sqlalchemy/dialects/mysql/dml.py

@@ -0,0 +1,175 @@
+from ... import exc
+from ... import util
+from ...sql.base import _exclusive_against
+from ...sql.base import _generative
+from ...sql.base import ColumnCollection
+from ...sql.dml import Insert as StandardInsert
+from ...sql.elements import ClauseElement
+from ...sql.expression import alias
+from ...util.langhelpers import public_factory
+
+
+__all__ = ("Insert", "insert")
+
+
+class Insert(StandardInsert):
+    """MySQL-specific implementation of INSERT.
+
+    Adds methods for MySQL-specific syntaxes such as ON DUPLICATE KEY UPDATE.
+
+    The :class:`~.mysql.Insert` object is created using the
+    :func:`sqlalchemy.dialects.mysql.insert` function.
+
+    .. versionadded:: 1.2
+
+    """
+
+    stringify_dialect = "mysql"
+    inherit_cache = False
+
+    @property
+    def inserted(self):
+        """Provide the "inserted" namespace for an ON DUPLICATE KEY UPDATE
+        statement
+
+        MySQL's ON DUPLICATE KEY UPDATE clause allows reference to the row
+        that would be inserted, via a special function called ``VALUES()``.
+        This attribute provides all columns in this row to be referenceable
+        such that they will render within a ``VALUES()`` function inside the
+        ON DUPLICATE KEY UPDATE clause.    The attribute is named ``.inserted``
+        so as not to conflict with the existing
+        :meth:`_expression.Insert.values` method.
+
+        .. tip::  The :attr:`_mysql.Insert.inserted` attribute is an instance
+            of :class:`_expression.ColumnCollection`, which provides an
+            interface the same as that of the :attr:`_schema.Table.c`
+            collection described at :ref:`metadata_tables_and_columns`.
+            With this collection, ordinary names are accessible like attributes
+            (e.g. ``stmt.inserted.some_column``), but special names and
+            dictionary method names should be accessed using indexed access,
+            such as ``stmt.inserted["column name"]`` or
+            ``stmt.inserted["values"]``.  See the docstring for
+            :class:`_expression.ColumnCollection` for further examples.
+
+        .. seealso::
+
+            :ref:`mysql_insert_on_duplicate_key_update` - example of how
+            to use :attr:`_expression.Insert.inserted`
+
+        """
+        return self.inserted_alias.columns
+
+    @util.memoized_property
+    def inserted_alias(self):
+        return alias(self.table, name="inserted")
+
+    @_generative
+    @_exclusive_against(
+        "_post_values_clause",
+        msgs={
+            "_post_values_clause": "This Insert construct already "
+            "has an ON DUPLICATE KEY clause present"
+        },
+    )
+    def on_duplicate_key_update(self, *args, **kw):
+        r"""
+        Specifies the ON DUPLICATE KEY UPDATE clause.
+
+        :param \**kw:  Column keys linked to UPDATE values.  The
+         values may be any SQL expression or supported literal Python
+         values.
+
+        .. warning:: This dictionary does **not** take into account
+           Python-specified default UPDATE values or generation functions,
+           e.g. those specified using :paramref:`_schema.Column.onupdate`.
+           These values will not be exercised for an ON DUPLICATE KEY UPDATE
+           style of UPDATE, unless values are manually specified here.
+
+        :param \*args: As an alternative to passing key/value parameters,
+         a dictionary or list of 2-tuples can be passed as a single positional
+         argument.
+
+         Passing a single dictionary is equivalent to the keyword argument
+         form::
+
+            insert().on_duplicate_key_update({"name": "some name"})
+
+         Passing a list of 2-tuples indicates that the parameter assignments
+         in the UPDATE clause should be ordered as sent, in a manner similar
+         to that described for the :class:`_expression.Update`
+         construct overall
+         in :ref:`tutorial_parameter_ordered_updates`::
+
+            insert().on_duplicate_key_update(
+                [("name", "some name"), ("value", "some value")])
+
+         .. versionchanged:: 1.3 parameters can be specified as a dictionary
+            or list of 2-tuples; the latter form provides for parameter
+            ordering.
+
+
+        .. versionadded:: 1.2
+
+        .. seealso::
+
+            :ref:`mysql_insert_on_duplicate_key_update`
+
+        """
+        if args and kw:
+            raise exc.ArgumentError(
+                "Can't pass kwargs and positional arguments simultaneously"
+            )
+
+        if args:
+            if len(args) > 1:
+                raise exc.ArgumentError(
+                    "Only a single dictionary or list of tuples "
+                    "is accepted positionally."
+                )
+            values = args[0]
+        else:
+            values = kw
+
+        inserted_alias = getattr(self, "inserted_alias", None)
+        self._post_values_clause = OnDuplicateClause(inserted_alias, values)
+
+
+insert = public_factory(
+    Insert, ".dialects.mysql.insert", ".dialects.mysql.Insert"
+)
+
+
+class OnDuplicateClause(ClauseElement):
+    __visit_name__ = "on_duplicate_key_update"
+
+    _parameter_ordering = None
+
+    stringify_dialect = "mysql"
+
+    def __init__(self, inserted_alias, update):
+        self.inserted_alias = inserted_alias
+
+        # auto-detect that parameters should be ordered.   This is copied from
+        # Update._proces_colparams(), however we don't look for a special flag
+        # in this case since we are not disambiguating from other use cases as
+        # we are in Update.values().
+        if isinstance(update, list) and (
+            update and isinstance(update[0], tuple)
+        ):
+            self._parameter_ordering = [key for key, value in update]
+            update = dict(update)
+
+        if isinstance(update, dict):
+            if not update:
+                raise ValueError(
+                    "update parameter dictionary must not be empty"
+                )
+        elif isinstance(update, ColumnCollection):
+            update = dict(update)
+        else:
+            raise ValueError(
+                "update parameter must be a non-empty dictionary "
+                "or a ColumnCollection such as the `.c.` collection "
+                "of a Table object"
+            )
+        self.update = update

lib/sqlalchemy/dialects/mysql/enumerated.py

@@ -0,0 +1,263 @@
+# mysql/enumerated.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+import re
+
+from .types import _StringType
+from ... import exc
+from ... import sql
+from ... import util
+from ...sql import sqltypes
+from ...sql.base import NO_ARG
+
+
+class ENUM(sqltypes.NativeForEmulated, sqltypes.Enum, _StringType):
+    """MySQL ENUM type."""
+
+    __visit_name__ = "ENUM"
+
+    native_enum = True
+
+    def __init__(self, *enums, **kw):
+        """Construct an ENUM.
+
+        E.g.::
+
+          Column('myenum', ENUM("foo", "bar", "baz"))
+
+        :param enums: The range of valid values for this ENUM.  Values in
+          enums are not quoted, they will be escaped and surrounded by single
+          quotes when generating the schema.  This object may also be a
+          PEP-435-compliant enumerated type.
+
+          .. versionadded: 1.1 added support for PEP-435-compliant enumerated
+             types.
+
+        :param strict: This flag has no effect.
+
+         .. versionchanged:: The MySQL ENUM type as well as the base Enum
+            type now validates all Python data values.
+
+        :param charset: Optional, a column-level character set for this string
+          value.  Takes precedence to 'ascii' or 'unicode' short-hand.
+
+        :param collation: Optional, a column-level collation for this string
+          value.  Takes precedence to 'binary' short-hand.
+
+        :param ascii: Defaults to False: short-hand for the ``latin1``
+          character set, generates ASCII in schema.
+
+        :param unicode: Defaults to False: short-hand for the ``ucs2``
+          character set, generates UNICODE in schema.
+
+        :param binary: Defaults to False: short-hand, pick the binary
+          collation type that matches the column's character set.  Generates
+          BINARY in schema.  This does not affect the type of data stored,
+          only the collation of character data.
+
+        :param quoting: Not used. A warning will be raised if provided.
+
+        """
+        if kw.pop("quoting", NO_ARG) is not NO_ARG:
+            util.warn_deprecated_20(
+                "The 'quoting' parameter to :class:`.mysql.ENUM` is deprecated"
+                " and will be removed in a future release. "
+                "This parameter now has no effect."
+            )
+        kw.pop("strict", None)
+        self._enum_init(enums, kw)
+        _StringType.__init__(self, length=self.length, **kw)
+
+    @classmethod
+    def adapt_emulated_to_native(cls, impl, **kw):
+        """Produce a MySQL native :class:`.mysql.ENUM` from plain
+        :class:`.Enum`.
+
+        """
+        kw.setdefault("validate_strings", impl.validate_strings)
+        kw.setdefault("values_callable", impl.values_callable)
+        kw.setdefault("omit_aliases", impl._omit_aliases)
+        return cls(**kw)
+
+    def _object_value_for_elem(self, elem):
+        # mysql sends back a blank string for any value that
+        # was persisted that was not in the enums; that is, it does no
+        # validation on the incoming data, it "truncates" it to be
+        # the blank string.  Return it straight.
+        if elem == "":
+            return elem
+        else:
+            return super(ENUM, self)._object_value_for_elem(elem)
+
+    def __repr__(self):
+        return util.generic_repr(
+            self, to_inspect=[ENUM, _StringType, sqltypes.Enum]
+        )
+
+
+class SET(_StringType):
+    """MySQL SET type."""
+
+    __visit_name__ = "SET"
+
+    def __init__(self, *values, **kw):
+        """Construct a SET.
+
+        E.g.::
+
+          Column('myset', SET("foo", "bar", "baz"))
+
+
+        The list of potential values is required in the case that this
+        set will be used to generate DDL for a table, or if the
+        :paramref:`.SET.retrieve_as_bitwise` flag is set to True.
+
+        :param values: The range of valid values for this SET. The values
+          are not quoted, they will be escaped and surrounded by single
+          quotes when generating the schema.
+
+        :param convert_unicode: Same flag as that of
+         :paramref:`.String.convert_unicode`.
+
+        :param collation: same as that of :paramref:`.String.collation`
+
+        :param charset: same as that of :paramref:`.VARCHAR.charset`.
+
+        :param ascii: same as that of :paramref:`.VARCHAR.ascii`.
+
+        :param unicode: same as that of :paramref:`.VARCHAR.unicode`.
+
+        :param binary: same as that of :paramref:`.VARCHAR.binary`.
+
+        :param retrieve_as_bitwise: if True, the data for the set type will be
+          persisted and selected using an integer value, where a set is coerced
+          into a bitwise mask for persistence.  MySQL allows this mode which
+          has the advantage of being able to store values unambiguously,
+          such as the blank string ``''``.   The datatype will appear
+          as the expression ``col + 0`` in a SELECT statement, so that the
+          value is coerced into an integer value in result sets.
+          This flag is required if one wishes
+          to persist a set that can store the blank string ``''`` as a value.
+
+          .. warning::
+
+            When using :paramref:`.mysql.SET.retrieve_as_bitwise`, it is
+            essential that the list of set values is expressed in the
+            **exact same order** as exists on the MySQL database.
+
+          .. versionadded:: 1.0.0
+
+        :param quoting: Not used. A warning will be raised if passed.
+
+        """
+        if kw.pop("quoting", NO_ARG) is not NO_ARG:
+            util.warn_deprecated_20(
+                "The 'quoting' parameter to :class:`.mysql.SET` is deprecated"
+                " and will be removed in a future release. "
+                "This parameter now has no effect."
+            )
+        self.retrieve_as_bitwise = kw.pop("retrieve_as_bitwise", False)
+        self.values = tuple(values)
+        if not self.retrieve_as_bitwise and "" in values:
+            raise exc.ArgumentError(
+                "Can't use the blank value '' in a SET without "
+                "setting retrieve_as_bitwise=True"
+            )
+        if self.retrieve_as_bitwise:
+            self._bitmap = dict(
+                (value, 2 ** idx) for idx, value in enumerate(self.values)
+            )
+            self._bitmap.update(
+                (2 ** idx, value) for idx, value in enumerate(self.values)
+            )
+        length = max([len(v) for v in values] + [0])
+        kw.setdefault("length", length)
+        super(SET, self).__init__(**kw)
+
+    def column_expression(self, colexpr):
+        if self.retrieve_as_bitwise:
+            return sql.type_coerce(
+                sql.type_coerce(colexpr, sqltypes.Integer) + 0, self
+            )
+        else:
+            return colexpr
+
+    def result_processor(self, dialect, coltype):
+        if self.retrieve_as_bitwise:
+
+            def process(value):
+                if value is not None:
+                    value = int(value)
+
+                    return set(util.map_bits(self._bitmap.__getitem__, value))
+                else:
+                    return None
+
+        else:
+            super_convert = super(SET, self).result_processor(dialect, coltype)
+
+            def process(value):
+                if isinstance(value, util.string_types):
+                    # MySQLdb returns a string, let's parse
+                    if super_convert:
+                        value = super_convert(value)
+                    return set(re.findall(r"[^,]+", value))
+                else:
+                    # mysql-connector-python does a naive
+                    # split(",") which throws in an empty string
+                    if value is not None:
+                        value.discard("")
+                    return value
+
+        return process
+
+    def bind_processor(self, dialect):
+        super_convert = super(SET, self).bind_processor(dialect)
+        if self.retrieve_as_bitwise:
+
+            def process(value):
+                if value is None:
+                    return None
+                elif isinstance(value, util.int_types + util.string_types):
+                    if super_convert:
+                        return super_convert(value)
+                    else:
+                        return value
+                else:
+                    int_value = 0
+                    for v in value:
+                        int_value |= self._bitmap[v]
+                    return int_value
+
+        else:
+
+            def process(value):
+                # accept strings and int (actually bitflag) values directly
+                if value is not None and not isinstance(
+                    value, util.int_types + util.string_types
+                ):
+                    value = ",".join(value)
+
+                if super_convert:
+                    return super_convert(value)
+                else:
+                    return value
+
+        return process
+
+    def adapt(self, impltype, **kw):
+        kw["retrieve_as_bitwise"] = self.retrieve_as_bitwise
+        return util.constructor_copy(self, impltype, *self.values, **kw)
+
+    def __repr__(self):
+        return util.generic_repr(
+            self,
+            to_inspect=[SET, _StringType],
+            additional_kw=[
+                ("retrieve_as_bitwise", False),
+            ],
+        )

lib/sqlalchemy/dialects/mysql/expression.py

@@ -0,0 +1,130 @@
+from ... import exc
+from ... import util
+from ...sql import coercions
+from ...sql import elements
+from ...sql import operators
+from ...sql import roles
+from ...sql.base import _generative
+from ...sql.base import Generative
+
+
+class match(Generative, elements.BinaryExpression):
+    """Produce a ``MATCH (X, Y) AGAINST ('TEXT')`` clause.
+
+    E.g.::
+
+        from sqlalchemy import desc
+        from sqlalchemy.dialects.mysql import match
+
+        match_expr = match(
+            users_table.c.firstname,
+            users_table.c.lastname,
+            against="Firstname Lastname",
+        )
+
+        stmt = (
+            select(users_table)
+            .where(match_expr.in_boolean_mode())
+            .order_by(desc(match_expr))
+        )
+
+    Would produce SQL resembling::
+
+        SELECT id, firstname, lastname
+        FROM user
+        WHERE MATCH(firstname, lastname) AGAINST (:param_1 IN BOOLEAN MODE)
+        ORDER BY MATCH(firstname, lastname) AGAINST (:param_2) DESC
+
+    The :func:`_mysql.match` function is a standalone version of the
+    :meth:`_sql.ColumnElement.match` method available on all
+    SQL expressions, as when :meth:`_expression.ColumnElement.match` is
+    used, but allows to pass multiple columns
+
+    :param cols: column expressions to match against
+
+    :param against: expression to be compared towards
+
+    :param in_boolean_mode: boolean, set "boolean mode" to true
+
+    :param in_natural_language_mode: boolean , set "natural language" to true
+
+    :param with_query_expansion: boolean, set "query expansion" to true
+
+    .. versionadded:: 1.4.19
+
+    .. seealso::
+
+        :meth:`_expression.ColumnElement.match`
+
+    """
+
+    __visit_name__ = "mysql_match"
+
+    inherit_cache = True
+
+    def __init__(self, *cols, **kw):
+        if not cols:
+            raise exc.ArgumentError("columns are required")
+
+        against = kw.pop("against", None)
+
+        if against is None:
+            raise exc.ArgumentError("against is required")
+        against = coercions.expect(
+            roles.ExpressionElementRole,
+            against,
+        )
+
+        left = elements.BooleanClauseList._construct_raw(
+            operators.comma_op,
+            clauses=cols,
+        )
+        left.group = False
+
+        flags = util.immutabledict(
+            {
+                "mysql_boolean_mode": kw.pop("in_boolean_mode", False),
+                "mysql_natural_language": kw.pop(
+                    "in_natural_language_mode", False
+                ),
+                "mysql_query_expansion": kw.pop("with_query_expansion", False),
+            }
+        )
+
+        if kw:
+            raise exc.ArgumentError("unknown arguments: %s" % (", ".join(kw)))
+
+        super(match, self).__init__(
+            left, against, operators.match_op, modifiers=flags
+        )
+
+    @_generative
+    def in_boolean_mode(self):
+        """Apply the "IN BOOLEAN MODE" modifier to the MATCH expression.
+
+        :return: a new :class:`_mysql.match` instance with modifications
+         applied.
+        """
+
+        self.modifiers = self.modifiers.union({"mysql_boolean_mode": True})
+
+    @_generative
+    def in_natural_language_mode(self):
+        """Apply the "IN NATURAL LANGUAGE MODE" modifier to the MATCH
+        expression.
+
+        :return: a new :class:`_mysql.match` instance with modifications
+         applied.
+        """
+
+        self.modifiers = self.modifiers.union({"mysql_natural_language": True})
+
+    @_generative
+    def with_query_expansion(self):
+        """Apply the "WITH QUERY EXPANSION" modifier to the MATCH expression.
+
+        :return: a new :class:`_mysql.match` instance with modifications
+         applied.
+        """
+
+        self.modifiers = self.modifiers.union({"mysql_query_expansion": True})

lib/sqlalchemy/dialects/mysql/json.py

@@ -0,0 +1,84 @@
+# mysql/json.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from __future__ import absolute_import
+
+from ... import types as sqltypes
+
+
+class JSON(sqltypes.JSON):
+    """MySQL JSON type.
+
+    MySQL supports JSON as of version 5.7.
+    MariaDB supports JSON (as an alias for LONGTEXT) as of version 10.2.
+
+    :class:`_mysql.JSON` is used automatically whenever the base
+    :class:`_types.JSON` datatype is used against a MySQL or MariaDB backend.
+
+    .. seealso::
+
+        :class:`_types.JSON` - main documentation for the generic
+        cross-platform JSON datatype.
+
+    The :class:`.mysql.JSON` type supports persistence of JSON values
+    as well as the core index operations provided by :class:`_types.JSON`
+    datatype, by adapting the operations to render the ``JSON_EXTRACT``
+    function at the database level.
+
+    .. versionadded:: 1.1
+
+    """
+
+    pass
+
+
+class _FormatTypeMixin(object):
+    def _format_value(self, value):
+        raise NotImplementedError()
+
+    def bind_processor(self, dialect):
+        super_proc = self.string_bind_processor(dialect)
+
+        def process(value):
+            value = self._format_value(value)
+            if super_proc:
+                value = super_proc(value)
+            return value
+
+        return process
+
+    def literal_processor(self, dialect):
+        super_proc = self.string_literal_processor(dialect)
+
+        def process(value):
+            value = self._format_value(value)
+            if super_proc:
+                value = super_proc(value)
+            return value
+
+        return process
+
+
+class JSONIndexType(_FormatTypeMixin, sqltypes.JSON.JSONIndexType):
+    def _format_value(self, value):
+        if isinstance(value, int):
+            value = "$[%s]" % value
+        else:
+            value = '$."%s"' % value
+        return value
+
+
+class JSONPathType(_FormatTypeMixin, sqltypes.JSON.JSONPathType):
+    def _format_value(self, value):
+        return "$%s" % (
+            "".join(
+                [
+                    "[%s]" % elem if isinstance(elem, int) else '."%s"' % elem
+                    for elem in value
+                ]
+            )
+        )

lib/sqlalchemy/dialects/mysql/mariadb.py

@@ -0,0 +1,25 @@
+from .base import MariaDBIdentifierPreparer
+from .base import MySQLDialect
+
+
+class MariaDBDialect(MySQLDialect):
+    is_mariadb = True
+    supports_statement_cache = True
+    name = "mariadb"
+    preparer = MariaDBIdentifierPreparer
+
+
+def loader(driver):
+    driver_mod = __import__(
+        "sqlalchemy.dialects.mysql.%s" % driver
+    ).dialects.mysql
+    driver_cls = getattr(driver_mod, driver).dialect
+
+    return type(
+        "MariaDBDialect_%s" % driver,
+        (
+            MariaDBDialect,
+            driver_cls,
+        ),
+        {"supports_statement_cache": True},
+    )

lib/sqlalchemy/dialects/mysql/mariadbconnector.py

@@ -0,0 +1,240 @@
+# mysql/mariadbconnector.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""
+
+.. dialect:: mysql+mariadbconnector
+    :name: MariaDB Connector/Python
+    :dbapi: mariadb
+    :connectstring: mariadb+mariadbconnector://<user>:<password>@<host>[:<port>]/<dbname>
+    :url: https://pypi.org/project/mariadb/
+
+Driver Status
+-------------
+
+MariaDB Connector/Python enables Python programs to access MariaDB and MySQL
+databases using an API which is compliant with the Python DB API 2.0 (PEP-249).
+It is written in C and uses MariaDB Connector/C client library for client server
+communication.
+
+Note that the default driver for a ``mariadb://`` connection URI continues to
+be ``mysqldb``. ``mariadb+mariadbconnector://`` is required to use this driver.
+
+.. mariadb: https://github.com/mariadb-corporation/mariadb-connector-python
+
+"""  # noqa
+import re
+
+from .base import MySQLCompiler
+from .base import MySQLDialect
+from .base import MySQLExecutionContext
+from ... import sql
+from ... import util
+
+mariadb_cpy_minimum_version = (1, 0, 1)
+
+
+class MySQLExecutionContext_mariadbconnector(MySQLExecutionContext):
+    _lastrowid = None
+
+    def create_server_side_cursor(self):
+        return self._dbapi_connection.cursor(buffered=False)
+
+    def create_default_cursor(self):
+        return self._dbapi_connection.cursor(buffered=True)
+
+    def post_exec(self):
+        if self.isinsert and self.compiled.postfetch_lastrowid:
+            self._lastrowid = self.cursor.lastrowid
+
+    def get_lastrowid(self):
+        return self._lastrowid
+
+
+class MySQLCompiler_mariadbconnector(MySQLCompiler):
+    pass
+
+
+class MySQLDialect_mariadbconnector(MySQLDialect):
+    driver = "mariadbconnector"
+    supports_statement_cache = True
+
+    # set this to True at the module level to prevent the driver from running
+    # against a backend that server detects as MySQL. currently this appears to
+    # be unnecessary as MariaDB client libraries have always worked against
+    # MySQL databases.   However, if this changes at some point, this can be
+    # adjusted, but PLEASE ADD A TEST in test/dialect/mysql/test_dialect.py if
+    # this change is made at some point to ensure the correct exception
+    # is raised at the correct point when running the driver against
+    # a MySQL backend.
+    # is_mariadb = True
+
+    supports_unicode_statements = True
+    encoding = "utf8mb4"
+    convert_unicode = True
+    supports_sane_rowcount = True
+    supports_sane_multi_rowcount = True
+    supports_native_decimal = True
+    default_paramstyle = "qmark"
+    execution_ctx_cls = MySQLExecutionContext_mariadbconnector
+    statement_compiler = MySQLCompiler_mariadbconnector
+
+    supports_server_side_cursors = True
+
+    @util.memoized_property
+    def _dbapi_version(self):
+        if self.dbapi and hasattr(self.dbapi, "__version__"):
+            return tuple(
+                [
+                    int(x)
+                    for x in re.findall(
+                        r"(\d+)(?:[-\.]?|$)", self.dbapi.__version__
+                    )
+                ]
+            )
+        else:
+            return (99, 99, 99)
+
+    def __init__(self, **kwargs):
+        super(MySQLDialect_mariadbconnector, self).__init__(**kwargs)
+        self.paramstyle = "qmark"
+        if self.dbapi is not None:
+            if self._dbapi_version < mariadb_cpy_minimum_version:
+                raise NotImplementedError(
+                    "The minimum required version for MariaDB "
+                    "Connector/Python is %s"
+                    % ".".join(str(x) for x in mariadb_cpy_minimum_version)
+                )
+
+    @classmethod
+    def dbapi(cls):
+        return __import__("mariadb")
+
+    def is_disconnect(self, e, connection, cursor):
+        if super(MySQLDialect_mariadbconnector, self).is_disconnect(
+            e, connection, cursor
+        ):
+            return True
+        elif isinstance(e, self.dbapi.Error):
+            str_e = str(e).lower()
+            return "not connected" in str_e or "isn't valid" in str_e
+        else:
+            return False
+
+    def create_connect_args(self, url):
+        opts = url.translate_connect_args()
+
+        int_params = [
+            "connect_timeout",
+            "read_timeout",
+            "write_timeout",
+            "client_flag",
+            "port",
+            "pool_size",
+        ]
+        bool_params = [
+            "local_infile",
+            "ssl_verify_cert",
+            "ssl",
+            "pool_reset_connection",
+        ]
+
+        for key in int_params:
+            util.coerce_kw_type(opts, key, int)
+        for key in bool_params:
+            util.coerce_kw_type(opts, key, bool)
+
+        # FOUND_ROWS must be set in CLIENT_FLAGS to enable
+        # supports_sane_rowcount.
+        client_flag = opts.get("client_flag", 0)
+        if self.dbapi is not None:
+            try:
+                CLIENT_FLAGS = __import__(
+                    self.dbapi.__name__ + ".constants.CLIENT"
+                ).constants.CLIENT
+                client_flag |= CLIENT_FLAGS.FOUND_ROWS
+            except (AttributeError, ImportError):
+                self.supports_sane_rowcount = False
+            opts["client_flag"] = client_flag
+        return [[], opts]
+
+    def _extract_error_code(self, exception):
+        try:
+            rc = exception.errno
+        except:
+            rc = -1
+        return rc
+
+    def _detect_charset(self, connection):
+        return "utf8mb4"
+
+    _isolation_lookup = set(
+        [
+            "SERIALIZABLE",
+            "READ UNCOMMITTED",
+            "READ COMMITTED",
+            "REPEATABLE READ",
+            "AUTOCOMMIT",
+        ]
+    )
+
+    def _set_isolation_level(self, connection, level):
+        if level == "AUTOCOMMIT":
+            connection.autocommit = True
+        else:
+            connection.autocommit = False
+            super(MySQLDialect_mariadbconnector, self)._set_isolation_level(
+                connection, level
+            )
+
+    def do_begin_twophase(self, connection, xid):
+        connection.execute(
+            sql.text("XA BEGIN :xid").bindparams(
+                sql.bindparam("xid", xid, literal_execute=True)
+            )
+        )
+
+    def do_prepare_twophase(self, connection, xid):
+        connection.execute(
+            sql.text("XA END :xid").bindparams(
+                sql.bindparam("xid", xid, literal_execute=True)
+            )
+        )
+        connection.execute(
+            sql.text("XA PREPARE :xid").bindparams(
+                sql.bindparam("xid", xid, literal_execute=True)
+            )
+        )
+
+    def do_rollback_twophase(
+        self, connection, xid, is_prepared=True, recover=False
+    ):
+        if not is_prepared:
+            connection.execute(
+                sql.text("XA END :xid").bindparams(
+                    sql.bindparam("xid", xid, literal_execute=True)
+                )
+            )
+        connection.execute(
+            sql.text("XA ROLLBACK :xid").bindparams(
+                sql.bindparam("xid", xid, literal_execute=True)
+            )
+        )
+
+    def do_commit_twophase(
+        self, connection, xid, is_prepared=True, recover=False
+    ):
+        if not is_prepared:
+            self.do_prepare_twophase(connection, xid)
+        connection.execute(
+            sql.text("XA COMMIT :xid").bindparams(
+                sql.bindparam("xid", xid, literal_execute=True)
+            )
+        )
+
+
+dialect = MySQLDialect_mariadbconnector

lib/sqlalchemy/dialects/mysql/mysqlconnector.py

@@ -0,0 +1,240 @@
+# mysql/mysqlconnector.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+r"""
+.. dialect:: mysql+mysqlconnector
+    :name: MySQL Connector/Python
+    :dbapi: myconnpy
+    :connectstring: mysql+mysqlconnector://<user>:<password>@<host>[:<port>]/<dbname>
+    :url: https://pypi.org/project/mysql-connector-python/
+
+.. note::
+
+    The MySQL Connector/Python DBAPI has had many issues since its release,
+    some of which may remain unresolved, and the mysqlconnector dialect is
+    **not tested as part of SQLAlchemy's continuous integration**.
+    The recommended MySQL dialects are mysqlclient and PyMySQL.
+
+"""  # noqa
+
+import re
+
+from .base import BIT
+from .base import MySQLCompiler
+from .base import MySQLDialect
+from .base import MySQLIdentifierPreparer
+from ... import processors
+from ... import util
+
+
+class MySQLCompiler_mysqlconnector(MySQLCompiler):
+    def visit_mod_binary(self, binary, operator, **kw):
+        if self.dialect._mysqlconnector_double_percents:
+            return (
+                self.process(binary.left, **kw)
+                + " %% "
+                + self.process(binary.right, **kw)
+            )
+        else:
+            return (
+                self.process(binary.left, **kw)
+                + " % "
+                + self.process(binary.right, **kw)
+            )
+
+    def post_process_text(self, text):
+        if self.dialect._mysqlconnector_double_percents:
+            return text.replace("%", "%%")
+        else:
+            return text
+
+    def escape_literal_column(self, text):
+        if self.dialect._mysqlconnector_double_percents:
+            return text.replace("%", "%%")
+        else:
+            return text
+
+
+class MySQLIdentifierPreparer_mysqlconnector(MySQLIdentifierPreparer):
+    @property
+    def _double_percents(self):
+        return self.dialect._mysqlconnector_double_percents
+
+    @_double_percents.setter
+    def _double_percents(self, value):
+        pass
+
+    def _escape_identifier(self, value):
+        value = value.replace(self.escape_quote, self.escape_to_quote)
+        if self.dialect._mysqlconnector_double_percents:
+            return value.replace("%", "%%")
+        else:
+            return value
+
+
+class _myconnpyBIT(BIT):
+    def result_processor(self, dialect, coltype):
+        """MySQL-connector already converts mysql bits, so."""
+
+        return None
+
+
+class MySQLDialect_mysqlconnector(MySQLDialect):
+    driver = "mysqlconnector"
+    supports_statement_cache = True
+
+    supports_unicode_binds = True
+
+    supports_sane_rowcount = True
+    supports_sane_multi_rowcount = True
+
+    supports_native_decimal = True
+
+    default_paramstyle = "format"
+    statement_compiler = MySQLCompiler_mysqlconnector
+
+    preparer = MySQLIdentifierPreparer_mysqlconnector
+
+    colspecs = util.update_copy(MySQLDialect.colspecs, {BIT: _myconnpyBIT})
+
+    def __init__(self, *arg, **kw):
+        super(MySQLDialect_mysqlconnector, self).__init__(*arg, **kw)
+
+        # hack description encoding since mysqlconnector randomly
+        # returns bytes or not
+        self._description_decoder = (
+            processors.to_conditional_unicode_processor_factory
+        )(self.description_encoding)
+
+    def _check_unicode_description(self, connection):
+        # hack description encoding since mysqlconnector randomly
+        # returns bytes or not
+        return False
+
+    @property
+    def description_encoding(self):
+        # total guess
+        return "latin-1"
+
+    @util.memoized_property
+    def supports_unicode_statements(self):
+        return util.py3k or self._mysqlconnector_version_info > (2, 0)
+
+    @classmethod
+    def dbapi(cls):
+        from mysql import connector
+
+        return connector
+
+    def do_ping(self, dbapi_connection):
+        try:
+            dbapi_connection.ping(False)
+        except self.dbapi.Error as err:
+            if self.is_disconnect(err, dbapi_connection, None):
+                return False
+            else:
+                raise
+        else:
+            return True
+
+    def create_connect_args(self, url):
+        opts = url.translate_connect_args(username="user")
+
+        opts.update(url.query)
+
+        util.coerce_kw_type(opts, "allow_local_infile", bool)
+        util.coerce_kw_type(opts, "autocommit", bool)
+        util.coerce_kw_type(opts, "buffered", bool)
+        util.coerce_kw_type(opts, "compress", bool)
+        util.coerce_kw_type(opts, "connection_timeout", int)
+        util.coerce_kw_type(opts, "connect_timeout", int)
+        util.coerce_kw_type(opts, "consume_results", bool)
+        util.coerce_kw_type(opts, "force_ipv6", bool)
+        util.coerce_kw_type(opts, "get_warnings", bool)
+        util.coerce_kw_type(opts, "pool_reset_session", bool)
+        util.coerce_kw_type(opts, "pool_size", int)
+        util.coerce_kw_type(opts, "raise_on_warnings", bool)
+        util.coerce_kw_type(opts, "raw", bool)
+        util.coerce_kw_type(opts, "ssl_verify_cert", bool)
+        util.coerce_kw_type(opts, "use_pure", bool)
+        util.coerce_kw_type(opts, "use_unicode", bool)
+
+        # unfortunately, MySQL/connector python refuses to release a
+        # cursor without reading fully, so non-buffered isn't an option
+        opts.setdefault("buffered", True)
+
+        # FOUND_ROWS must be set in ClientFlag to enable
+        # supports_sane_rowcount.
+        if self.dbapi is not None:
+            try:
+                from mysql.connector.constants import ClientFlag
+
+                client_flags = opts.get(
+                    "client_flags", ClientFlag.get_default()
+                )
+                client_flags |= ClientFlag.FOUND_ROWS
+                opts["client_flags"] = client_flags
+            except Exception:
+                pass
+        return [[], opts]
+
+    @util.memoized_property
+    def _mysqlconnector_version_info(self):
+        if self.dbapi and hasattr(self.dbapi, "__version__"):
+            m = re.match(r"(\d+)\.(\d+)(?:\.(\d+))?", self.dbapi.__version__)
+            if m:
+                return tuple(int(x) for x in m.group(1, 2, 3) if x is not None)
+
+    @util.memoized_property
+    def _mysqlconnector_double_percents(self):
+        return not util.py3k and self._mysqlconnector_version_info < (2, 0)
+
+    def _detect_charset(self, connection):
+        return connection.connection.charset
+
+    def _extract_error_code(self, exception):
+        return exception.errno
+
+    def is_disconnect(self, e, connection, cursor):
+        errnos = (2006, 2013, 2014, 2045, 2055, 2048)
+        exceptions = (self.dbapi.OperationalError, self.dbapi.InterfaceError)
+        if isinstance(e, exceptions):
+            return (
+                e.errno in errnos
+                or "MySQL Connection not available." in str(e)
+                or "Connection to MySQL is not available" in str(e)
+            )
+        else:
+            return False
+
+    def _compat_fetchall(self, rp, charset=None):
+        return rp.fetchall()
+
+    def _compat_fetchone(self, rp, charset=None):
+        return rp.fetchone()
+
+    _isolation_lookup = set(
+        [
+            "SERIALIZABLE",
+            "READ UNCOMMITTED",
+            "READ COMMITTED",
+            "REPEATABLE READ",
+            "AUTOCOMMIT",
+        ]
+    )
+
+    def _set_isolation_level(self, connection, level):
+        if level == "AUTOCOMMIT":
+            connection.autocommit = True
+        else:
+            connection.autocommit = False
+            super(MySQLDialect_mysqlconnector, self)._set_isolation_level(
+                connection, level
+            )
+
+
+dialect = MySQLDialect_mysqlconnector

lib/sqlalchemy/dialects/mysql/mysqldb.py

@@ -0,0 +1,331 @@
+# mysql/mysqldb.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""
+
+.. dialect:: mysql+mysqldb
+    :name: mysqlclient (maintained fork of MySQL-Python)
+    :dbapi: mysqldb
+    :connectstring: mysql+mysqldb://<user>:<password>@<host>[:<port>]/<dbname>
+    :url: https://pypi.org/project/mysqlclient/
+
+Driver Status
+-------------
+
+The mysqlclient DBAPI is a maintained fork of the
+`MySQL-Python <https://sourceforge.net/projects/mysql-python>`_ DBAPI
+that is no longer maintained.  `mysqlclient`_ supports Python 2 and Python 3
+and is very stable.
+
+.. _mysqlclient: https://github.com/PyMySQL/mysqlclient-python
+
+.. _mysqldb_unicode:
+
+Unicode
+-------
+
+Please see :ref:`mysql_unicode` for current recommendations on unicode
+handling.
+
+.. _mysqldb_ssl:
+
+SSL Connections
+----------------
+
+The mysqlclient and PyMySQL DBAPIs accept an additional dictionary under the
+key "ssl", which may be specified using the
+:paramref:`_sa.create_engine.connect_args` dictionary::
+
+    engine = create_engine(
+        "mysql+mysqldb://scott:tiger@192.168.0.134/test",
+        connect_args={
+            "ssl": {
+                "ssl_ca": "/home/gord/client-ssl/ca.pem",
+                "ssl_cert": "/home/gord/client-ssl/client-cert.pem",
+                "ssl_key": "/home/gord/client-ssl/client-key.pem"
+            }
+        }
+    )
+
+For convenience, the following keys may also be specified inline within the URL
+where they will be interpreted into the "ssl" dictionary automatically:
+"ssl_ca", "ssl_cert", "ssl_key", "ssl_capath", "ssl_cipher",
+"ssl_check_hostname". An example is as follows::
+
+    connection_uri = (
+        "mysql+mysqldb://scott:tiger@192.168.0.134/test"
+        "?ssl_ca=/home/gord/client-ssl/ca.pem"
+        "&ssl_cert=/home/gord/client-ssl/client-cert.pem"
+        "&ssl_key=/home/gord/client-ssl/client-key.pem"
+    )
+
+If the server uses an automatically-generated certificate that is self-signed
+or does not match the host name (as seen from the client), it may also be
+necessary to indicate ``ssl_check_hostname=false``::
+
+    connection_uri = (
+        "mysql+pymysql://scott:tiger@192.168.0.134/test"
+        "?ssl_ca=/home/gord/client-ssl/ca.pem"
+        "&ssl_cert=/home/gord/client-ssl/client-cert.pem"
+        "&ssl_key=/home/gord/client-ssl/client-key.pem"
+        "&ssl_check_hostname=false"
+    )
+
+
+.. seealso::
+
+    :ref:`pymysql_ssl` in the PyMySQL dialect
+
+
+Using MySQLdb with Google Cloud SQL
+-----------------------------------
+
+Google Cloud SQL now recommends use of the MySQLdb dialect.  Connect
+using a URL like the following::
+
+    mysql+mysqldb://root@/<dbname>?unix_socket=/cloudsql/<projectid>:<instancename>
+
+Server Side Cursors
+-------------------
+
+The mysqldb dialect supports server-side cursors. See :ref:`mysql_ss_cursors`.
+
+"""
+
+import re
+
+from .base import MySQLCompiler
+from .base import MySQLDialect
+from .base import MySQLExecutionContext
+from .base import MySQLIdentifierPreparer
+from .base import TEXT
+from ... import sql
+from ... import util
+
+
+class MySQLExecutionContext_mysqldb(MySQLExecutionContext):
+    @property
+    def rowcount(self):
+        if hasattr(self, "_rowcount"):
+            return self._rowcount
+        else:
+            return self.cursor.rowcount
+
+
+class MySQLCompiler_mysqldb(MySQLCompiler):
+    pass
+
+
+class MySQLDialect_mysqldb(MySQLDialect):
+    driver = "mysqldb"
+    supports_statement_cache = True
+    supports_unicode_statements = True
+    supports_sane_rowcount = True
+    supports_sane_multi_rowcount = True
+
+    supports_native_decimal = True
+
+    default_paramstyle = "format"
+    execution_ctx_cls = MySQLExecutionContext_mysqldb
+    statement_compiler = MySQLCompiler_mysqldb
+    preparer = MySQLIdentifierPreparer
+
+    def __init__(self, **kwargs):
+        super(MySQLDialect_mysqldb, self).__init__(**kwargs)
+        self._mysql_dbapi_version = (
+            self._parse_dbapi_version(self.dbapi.__version__)
+            if self.dbapi is not None and hasattr(self.dbapi, "__version__")
+            else (0, 0, 0)
+        )
+
+    def _parse_dbapi_version(self, version):
+        m = re.match(r"(\d+)\.(\d+)(?:\.(\d+))?", version)
+        if m:
+            return tuple(int(x) for x in m.group(1, 2, 3) if x is not None)
+        else:
+            return (0, 0, 0)
+
+    @util.langhelpers.memoized_property
+    def supports_server_side_cursors(self):
+        try:
+            cursors = __import__("MySQLdb.cursors").cursors
+            self._sscursor = cursors.SSCursor
+            return True
+        except (ImportError, AttributeError):
+            return False
+
+    @classmethod
+    def dbapi(cls):
+        return __import__("MySQLdb")
+
+    def on_connect(self):
+        super_ = super(MySQLDialect_mysqldb, self).on_connect()
+
+        def on_connect(conn):
+            if super_ is not None:
+                super_(conn)
+
+            charset_name = conn.character_set_name()
+
+            if charset_name is not None:
+                cursor = conn.cursor()
+                cursor.execute("SET NAMES %s" % charset_name)
+                cursor.close()
+
+        return on_connect
+
+    def do_ping(self, dbapi_connection):
+        try:
+            dbapi_connection.ping(False)
+        except self.dbapi.Error as err:
+            if self.is_disconnect(err, dbapi_connection, None):
+                return False
+            else:
+                raise
+        else:
+            return True
+
+    def do_executemany(self, cursor, statement, parameters, context=None):
+        rowcount = cursor.executemany(statement, parameters)
+        if context is not None:
+            context._rowcount = rowcount
+
+    def _check_unicode_returns(self, connection):
+        # work around issue fixed in
+        # https://github.com/farcepest/MySQLdb1/commit/cd44524fef63bd3fcb71947392326e9742d520e8
+        # specific issue w/ the utf8mb4_bin collation and unicode returns
+
+        collation = connection.exec_driver_sql(
+            "show collation where %s = 'utf8mb4' and %s = 'utf8mb4_bin'"
+            % (
+                self.identifier_preparer.quote("Charset"),
+                self.identifier_preparer.quote("Collation"),
+            )
+        ).scalar()
+        has_utf8mb4_bin = self.server_version_info > (5,) and collation
+        if has_utf8mb4_bin:
+            additional_tests = [
+                sql.collate(
+                    sql.cast(
+                        sql.literal_column("'test collated returns'"),
+                        TEXT(charset="utf8mb4"),
+                    ),
+                    "utf8mb4_bin",
+                )
+            ]
+        else:
+            additional_tests = []
+        return super(MySQLDialect_mysqldb, self)._check_unicode_returns(
+            connection, additional_tests
+        )
+
+    def create_connect_args(self, url, _translate_args=None):
+        if _translate_args is None:
+            _translate_args = dict(
+                database="db", username="user", password="passwd"
+            )
+
+        opts = url.translate_connect_args(**_translate_args)
+        opts.update(url.query)
+
+        util.coerce_kw_type(opts, "compress", bool)
+        util.coerce_kw_type(opts, "connect_timeout", int)
+        util.coerce_kw_type(opts, "read_timeout", int)
+        util.coerce_kw_type(opts, "write_timeout", int)
+        util.coerce_kw_type(opts, "client_flag", int)
+        util.coerce_kw_type(opts, "local_infile", int)
+        # Note: using either of the below will cause all strings to be
+        # returned as Unicode, both in raw SQL operations and with column
+        # types like String and MSString.
+        util.coerce_kw_type(opts, "use_unicode", bool)
+        util.coerce_kw_type(opts, "charset", str)
+
+        # Rich values 'cursorclass' and 'conv' are not supported via
+        # query string.
+
+        ssl = {}
+        keys = [
+            ("ssl_ca", str),
+            ("ssl_key", str),
+            ("ssl_cert", str),
+            ("ssl_capath", str),
+            ("ssl_cipher", str),
+            ("ssl_check_hostname", bool),
+        ]
+        for key, kw_type in keys:
+            if key in opts:
+                ssl[key[4:]] = opts[key]
+                util.coerce_kw_type(ssl, key[4:], kw_type)
+                del opts[key]
+        if ssl:
+            opts["ssl"] = ssl
+
+        # FOUND_ROWS must be set in CLIENT_FLAGS to enable
+        # supports_sane_rowcount.
+        client_flag = opts.get("client_flag", 0)
+
+        client_flag_found_rows = self._found_rows_client_flag()
+        if client_flag_found_rows is not None:
+            client_flag |= client_flag_found_rows
+            opts["client_flag"] = client_flag
+        return [[], opts]
+
+    def _found_rows_client_flag(self):
+        if self.dbapi is not None:
+            try:
+                CLIENT_FLAGS = __import__(
+                    self.dbapi.__name__ + ".constants.CLIENT"
+                ).constants.CLIENT
+            except (AttributeError, ImportError):
+                return None
+            else:
+                return CLIENT_FLAGS.FOUND_ROWS
+        else:
+            return None
+
+    def _extract_error_code(self, exception):
+        return exception.args[0]
+
+    def _detect_charset(self, connection):
+        """Sniff out the character set in use for connection results."""
+
+        try:
+            # note: the SQL here would be
+            # "SHOW VARIABLES LIKE 'character_set%%'"
+            cset_name = connection.connection.character_set_name
+        except AttributeError:
+            util.warn(
+                "No 'character_set_name' can be detected with "
+                "this MySQL-Python version; "
+                "please upgrade to a recent version of MySQL-Python.  "
+                "Assuming latin1."
+            )
+            return "latin1"
+        else:
+            return cset_name()
+
+    _isolation_lookup = set(
+        [
+            "SERIALIZABLE",
+            "READ UNCOMMITTED",
+            "READ COMMITTED",
+            "REPEATABLE READ",
+            "AUTOCOMMIT",
+        ]
+    )
+
+    def _set_isolation_level(self, connection, level):
+        if level == "AUTOCOMMIT":
+            connection.autocommit(True)
+        else:
+            connection.autocommit(False)
+            super(MySQLDialect_mysqldb, self)._set_isolation_level(
+                connection, level
+            )
+
+
+dialect = MySQLDialect_mysqldb

lib/sqlalchemy/dialects/mysql/oursql.py

@@ -0,0 +1,273 @@
+# mysql/oursql.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""
+
+.. dialect:: mysql+oursql
+    :name: OurSQL
+    :dbapi: oursql
+    :connectstring: mysql+oursql://<user>:<password>@<host>[:<port>]/<dbname>
+    :url: https://packages.python.org/oursql/
+
+.. note::
+
+    The OurSQL MySQL dialect is legacy and is no longer supported upstream,
+    and is **not tested as part of SQLAlchemy's continuous integration**.
+    The recommended MySQL dialects are mysqlclient and PyMySQL.
+
+.. deprecated:: 1.4 The OurSQL DBAPI is deprecated and will be removed
+   in a future version. Please use one of the supported DBAPIs to
+   connect to mysql.
+
+Unicode
+-------
+
+Please see :ref:`mysql_unicode` for current recommendations on unicode
+handling.
+
+
+"""
+
+
+from .base import BIT
+from .base import MySQLDialect
+from .base import MySQLExecutionContext
+from ... import types as sqltypes
+from ... import util
+
+
+class _oursqlBIT(BIT):
+    def result_processor(self, dialect, coltype):
+        """oursql already converts mysql bits, so."""
+
+        return None
+
+
+class MySQLExecutionContext_oursql(MySQLExecutionContext):
+    @property
+    def plain_query(self):
+        return self.execution_options.get("_oursql_plain_query", False)
+
+
+class MySQLDialect_oursql(MySQLDialect):
+    driver = "oursql"
+    supports_statement_cache = True
+
+    if util.py2k:
+        supports_unicode_binds = True
+        supports_unicode_statements = True
+
+    supports_native_decimal = True
+
+    supports_sane_rowcount = True
+    supports_sane_multi_rowcount = True
+    execution_ctx_cls = MySQLExecutionContext_oursql
+
+    colspecs = util.update_copy(
+        MySQLDialect.colspecs, {sqltypes.Time: sqltypes.Time, BIT: _oursqlBIT}
+    )
+
+    @classmethod
+    def dbapi(cls):
+        util.warn_deprecated(
+            "The OurSQL DBAPI is deprecated and will be removed "
+            "in a future version. Please use one of the supported DBAPIs to "
+            "connect to mysql.",
+            version="1.4",
+        )
+        return __import__("oursql")
+
+    def do_execute(self, cursor, statement, parameters, context=None):
+        """Provide an implementation of
+        *cursor.execute(statement, parameters)*."""
+
+        if context and context.plain_query:
+            cursor.execute(statement, plain_query=True)
+        else:
+            cursor.execute(statement, parameters)
+
+    def do_begin(self, connection):
+        connection.cursor().execute("BEGIN", plain_query=True)
+
+    def _xa_query(self, connection, query, xid):
+        if util.py2k:
+            arg = connection.connection._escape_string(xid)
+        else:
+            charset = self._connection_charset
+            arg = connection.connection._escape_string(
+                xid.encode(charset)
+            ).decode(charset)
+        arg = "'%s'" % arg
+        connection.execution_options(_oursql_plain_query=True).exec_driver_sql(
+            query % arg
+        )
+
+    # Because mysql is bad, these methods have to be
+    # reimplemented to use _PlainQuery. Basically, some queries
+    # refuse to return any data if they're run through
+    # the parameterized query API, or refuse to be parameterized
+    # in the first place.
+    def do_begin_twophase(self, connection, xid):
+        self._xa_query(connection, "XA BEGIN %s", xid)
+
+    def do_prepare_twophase(self, connection, xid):
+        self._xa_query(connection, "XA END %s", xid)
+        self._xa_query(connection, "XA PREPARE %s", xid)
+
+    def do_rollback_twophase(
+        self, connection, xid, is_prepared=True, recover=False
+    ):
+        if not is_prepared:
+            self._xa_query(connection, "XA END %s", xid)
+        self._xa_query(connection, "XA ROLLBACK %s", xid)
+
+    def do_commit_twophase(
+        self, connection, xid, is_prepared=True, recover=False
+    ):
+        if not is_prepared:
+            self.do_prepare_twophase(connection, xid)
+        self._xa_query(connection, "XA COMMIT %s", xid)
+
+    # Q: why didn't we need all these "plain_query" overrides earlier ?
+    # am i on a newer/older version of OurSQL ?
+    def has_table(self, connection, table_name, schema=None):
+        return MySQLDialect.has_table(
+            self,
+            connection.connect().execution_options(_oursql_plain_query=True),
+            table_name,
+            schema,
+        )
+
+    def get_table_options(self, connection, table_name, schema=None, **kw):
+        return MySQLDialect.get_table_options(
+            self,
+            connection.connect().execution_options(_oursql_plain_query=True),
+            table_name,
+            schema=schema,
+            **kw
+        )
+
+    def get_columns(self, connection, table_name, schema=None, **kw):
+        return MySQLDialect.get_columns(
+            self,
+            connection.connect().execution_options(_oursql_plain_query=True),
+            table_name,
+            schema=schema,
+            **kw
+        )
+
+    def get_view_names(self, connection, schema=None, **kw):
+        return MySQLDialect.get_view_names(
+            self,
+            connection.connect().execution_options(_oursql_plain_query=True),
+            schema=schema,
+            **kw
+        )
+
+    def get_table_names(self, connection, schema=None, **kw):
+        return MySQLDialect.get_table_names(
+            self,
+            connection.connect().execution_options(_oursql_plain_query=True),
+            schema,
+        )
+
+    def get_schema_names(self, connection, **kw):
+        return MySQLDialect.get_schema_names(
+            self,
+            connection.connect().execution_options(_oursql_plain_query=True),
+            **kw
+        )
+
+    def initialize(self, connection):
+        return MySQLDialect.initialize(
+            self, connection.execution_options(_oursql_plain_query=True)
+        )
+
+    def _show_create_table(
+        self, connection, table, charset=None, full_name=None
+    ):
+        return MySQLDialect._show_create_table(
+            self,
+            connection.connect(close_with_result=True).execution_options(
+                _oursql_plain_query=True
+            ),
+            table,
+            charset,
+            full_name,
+        )
+
+    def is_disconnect(self, e, connection, cursor):
+        if isinstance(e, self.dbapi.ProgrammingError):
+            return (
+                e.errno is None
+                and "cursor" not in e.args[1]
+                and e.args[1].endswith("closed")
+            )
+        else:
+            return e.errno in (2006, 2013, 2014, 2045, 2055)
+
+    def create_connect_args(self, url):
+        opts = url.translate_connect_args(
+            database="db", username="user", password="passwd"
+        )
+        opts.update(url.query)
+
+        util.coerce_kw_type(opts, "port", int)
+        util.coerce_kw_type(opts, "compress", bool)
+        util.coerce_kw_type(opts, "autoping", bool)
+        util.coerce_kw_type(opts, "raise_on_warnings", bool)
+
+        util.coerce_kw_type(opts, "default_charset", bool)
+        if opts.pop("default_charset", False):
+            opts["charset"] = None
+        else:
+            util.coerce_kw_type(opts, "charset", str)
+        opts["use_unicode"] = opts.get("use_unicode", True)
+        util.coerce_kw_type(opts, "use_unicode", bool)
+
+        # FOUND_ROWS must be set in CLIENT_FLAGS to enable
+        # supports_sane_rowcount.
+        opts.setdefault("found_rows", True)
+
+        ssl = {}
+        for key in [
+            "ssl_ca",
+            "ssl_key",
+            "ssl_cert",
+            "ssl_capath",
+            "ssl_cipher",
+        ]:
+            if key in opts:
+                ssl[key[4:]] = opts[key]
+                util.coerce_kw_type(ssl, key[4:], str)
+                del opts[key]
+        if ssl:
+            opts["ssl"] = ssl
+
+        return [[], opts]
+
+    def _extract_error_code(self, exception):
+        return exception.errno
+
+    def _detect_charset(self, connection):
+        """Sniff out the character set in use for connection results."""
+
+        return connection.connection.charset
+
+    def _compat_fetchall(self, rp, charset=None):
+        """oursql isn't super-broken like MySQLdb, yaaay."""
+        return rp.fetchall()
+
+    def _compat_fetchone(self, rp, charset=None):
+        """oursql isn't super-broken like MySQLdb, yaaay."""
+        return rp.fetchone()
+
+    def _compat_first(self, rp, charset=None):
+        return rp.first()
+
+
+dialect = MySQLDialect_oursql

lib/sqlalchemy/dialects/mysql/provision.py

@@ -0,0 +1,78 @@
+from ... import exc
+from ...testing.provision import configure_follower
+from ...testing.provision import create_db
+from ...testing.provision import drop_db
+from ...testing.provision import generate_driver_url
+from ...testing.provision import temp_table_keyword_args
+
+
+@generate_driver_url.for_db("mysql", "mariadb")
+def generate_driver_url(url, driver, query_str):
+    backend = url.get_backend_name()
+
+    # NOTE: at the moment, tests are running mariadbconnector
+    # against both mariadb and mysql backends.   if we want this to be
+    # limited, do the decision making here to reject a "mysql+mariadbconnector"
+    # URL.  Optionally also re-enable the module level
+    # MySQLDialect_mariadbconnector.is_mysql flag as well, which must include
+    # a unit and/or functional test.
+
+    # all the Jenkins tests have been running mysqlclient Python library
+    # built against mariadb client drivers for years against all MySQL /
+    # MariaDB versions going back to MySQL 5.6, currently they can talk
+    # to MySQL databases without problems.
+
+    if backend == "mysql":
+        dialect_cls = url.get_dialect()
+        if dialect_cls._is_mariadb_from_url(url):
+            backend = "mariadb"
+
+    new_url = url.set(
+        drivername="%s+%s" % (backend, driver)
+    ).update_query_string(query_str)
+
+    try:
+        new_url.get_dialect()
+    except exc.NoSuchModuleError:
+        return None
+    else:
+        return new_url
+
+
+@create_db.for_db("mysql", "mariadb")
+def _mysql_create_db(cfg, eng, ident):
+    with eng.begin() as conn:
+        try:
+            _mysql_drop_db(cfg, conn, ident)
+        except Exception:
+            pass
+
+    with eng.begin() as conn:
+        conn.exec_driver_sql(
+            "CREATE DATABASE %s CHARACTER SET utf8mb4" % ident
+        )
+        conn.exec_driver_sql(
+            "CREATE DATABASE %s_test_schema CHARACTER SET utf8mb4" % ident
+        )
+        conn.exec_driver_sql(
+            "CREATE DATABASE %s_test_schema_2 CHARACTER SET utf8mb4" % ident
+        )
+
+
+@configure_follower.for_db("mysql", "mariadb")
+def _mysql_configure_follower(config, ident):
+    config.test_schema = "%s_test_schema" % ident
+    config.test_schema_2 = "%s_test_schema_2" % ident
+
+
+@drop_db.for_db("mysql", "mariadb")
+def _mysql_drop_db(cfg, eng, ident):
+    with eng.begin() as conn:
+        conn.exec_driver_sql("DROP DATABASE %s_test_schema" % ident)
+        conn.exec_driver_sql("DROP DATABASE %s_test_schema_2" % ident)
+        conn.exec_driver_sql("DROP DATABASE %s" % ident)
+
+
+@temp_table_keyword_args.for_db("mysql", "mariadb")
+def _mysql_temp_table_keyword_args(cfg, eng):
+    return {"prefixes": ["TEMPORARY"]}

lib/sqlalchemy/dialects/mysql/pymysql.py

@@ -0,0 +1,98 @@
+# mysql/pymysql.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+r"""
+
+.. dialect:: mysql+pymysql
+    :name: PyMySQL
+    :dbapi: pymysql
+    :connectstring: mysql+pymysql://<username>:<password>@<host>/<dbname>[?<options>]
+    :url: https://pymysql.readthedocs.io/
+
+Unicode
+-------
+
+Please see :ref:`mysql_unicode` for current recommendations on unicode
+handling.
+
+.. _pymysql_ssl:
+
+SSL Connections
+------------------
+
+The PyMySQL DBAPI accepts the same SSL arguments as that of MySQLdb,
+described at :ref:`mysqldb_ssl`.   See that section for examples.
+
+
+MySQL-Python Compatibility
+--------------------------
+
+The pymysql DBAPI is a pure Python port of the MySQL-python (MySQLdb) driver,
+and targets 100% compatibility.   Most behavioral notes for MySQL-python apply
+to the pymysql driver as well.
+
+"""  # noqa
+
+from .mysqldb import MySQLDialect_mysqldb
+from ...util import langhelpers
+from ...util import py3k
+
+
+class MySQLDialect_pymysql(MySQLDialect_mysqldb):
+    driver = "pymysql"
+    supports_statement_cache = True
+
+    description_encoding = None
+
+    # generally, these two values should be both True
+    # or both False.   PyMySQL unicode tests pass all the way back
+    # to 0.4 either way.  See [ticket:3337]
+    supports_unicode_statements = True
+    supports_unicode_binds = True
+
+    @langhelpers.memoized_property
+    def supports_server_side_cursors(self):
+        try:
+            cursors = __import__("pymysql.cursors").cursors
+            self._sscursor = cursors.SSCursor
+            return True
+        except (ImportError, AttributeError):
+            return False
+
+    @classmethod
+    def dbapi(cls):
+        return __import__("pymysql")
+
+    def create_connect_args(self, url, _translate_args=None):
+        if _translate_args is None:
+            _translate_args = dict(username="user")
+        return super(MySQLDialect_pymysql, self).create_connect_args(
+            url, _translate_args=_translate_args
+        )
+
+    def is_disconnect(self, e, connection, cursor):
+        if super(MySQLDialect_pymysql, self).is_disconnect(
+            e, connection, cursor
+        ):
+            return True
+        elif isinstance(e, self.dbapi.Error):
+            str_e = str(e).lower()
+            return (
+                "already closed" in str_e or "connection was killed" in str_e
+            )
+        else:
+            return False
+
+    if py3k:
+
+        def _extract_error_code(self, exception):
+            if isinstance(exception.args[0], Exception):
+                exception = exception.args[0]
+            return exception.args[0]
+
+
+dialect = MySQLDialect_pymysql

lib/sqlalchemy/dialects/mysql/pyodbc.py

@@ -0,0 +1,136 @@
+# mysql/pyodbc.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+r"""
+
+
+.. dialect:: mysql+pyodbc
+    :name: PyODBC
+    :dbapi: pyodbc
+    :connectstring: mysql+pyodbc://<username>:<password>@<dsnname>
+    :url: https://pypi.org/project/pyodbc/
+
+.. note::
+
+    The PyODBC for MySQL dialect is **not tested as part of
+    SQLAlchemy's continuous integration**.
+    The recommended MySQL dialects are mysqlclient and PyMySQL.
+    However, if you want to use the mysql+pyodbc dialect and require
+    full support for ``utf8mb4`` characters (including supplementary
+    characters like emoji) be sure to use a current release of
+    MySQL Connector/ODBC and specify the "ANSI" (**not** "Unicode")
+    version of the driver in your DSN or connection string.
+
+Pass through exact pyodbc connection string::
+
+    import urllib
+    connection_string = (
+        'DRIVER=MySQL ODBC 8.0 ANSI Driver;'
+        'SERVER=localhost;'
+        'PORT=3307;'
+        'DATABASE=mydb;'
+        'UID=root;'
+        'PWD=(whatever);'
+        'charset=utf8mb4;'
+    )
+    params = urllib.parse.quote_plus(connection_string)
+    connection_uri = "mysql+pyodbc:///?odbc_connect=%s" % params
+
+"""  # noqa
+
+import re
+
+from .base import MySQLDialect
+from .base import MySQLExecutionContext
+from .types import TIME
+from ... import exc
+from ... import util
+from ...connectors.pyodbc import PyODBCConnector
+from ...sql.sqltypes import Time
+
+
+class _pyodbcTIME(TIME):
+    def result_processor(self, dialect, coltype):
+        def process(value):
+            # pyodbc returns a datetime.time object; no need to convert
+            return value
+
+        return process
+
+
+class MySQLExecutionContext_pyodbc(MySQLExecutionContext):
+    def get_lastrowid(self):
+        cursor = self.create_cursor()
+        cursor.execute("SELECT LAST_INSERT_ID()")
+        lastrowid = cursor.fetchone()[0]
+        cursor.close()
+        return lastrowid
+
+
+class MySQLDialect_pyodbc(PyODBCConnector, MySQLDialect):
+    supports_statement_cache = True
+    colspecs = util.update_copy(MySQLDialect.colspecs, {Time: _pyodbcTIME})
+    supports_unicode_statements = True
+    execution_ctx_cls = MySQLExecutionContext_pyodbc
+
+    pyodbc_driver_name = "MySQL"
+
+    def _detect_charset(self, connection):
+        """Sniff out the character set in use for connection results."""
+
+        # Prefer 'character_set_results' for the current connection over the
+        # value in the driver.  SET NAMES or individual variable SETs will
+        # change the charset without updating the driver's view of the world.
+        #
+        # If it's decided that issuing that sort of SQL leaves you SOL, then
+        # this can prefer the driver value.
+
+        # set this to None as _fetch_setting attempts to use it (None is OK)
+        self._connection_charset = None
+        try:
+            value = self._fetch_setting(connection, "character_set_client")
+            if value:
+                return value
+        except exc.DBAPIError:
+            pass
+
+        util.warn(
+            "Could not detect the connection character set.  "
+            "Assuming latin1."
+        )
+        return "latin1"
+
+    def _get_server_version_info(self, connection):
+        return MySQLDialect._get_server_version_info(self, connection)
+
+    def _extract_error_code(self, exception):
+        m = re.compile(r"\((\d+)\)").search(str(exception.args))
+        c = m.group(1)
+        if c:
+            return int(c)
+        else:
+            return None
+
+    def on_connect(self):
+        super_ = super(MySQLDialect_pyodbc, self).on_connect()
+
+        def on_connect(conn):
+            if super_ is not None:
+                super_(conn)
+
+            # declare Unicode encoding for pyodbc as per
+            #   https://github.com/mkleehammer/pyodbc/wiki/Unicode
+            pyodbc_SQL_CHAR = 1  # pyodbc.SQL_CHAR
+            pyodbc_SQL_WCHAR = -8  # pyodbc.SQL_WCHAR
+            conn.setdecoding(pyodbc_SQL_CHAR, encoding="utf-8")
+            conn.setdecoding(pyodbc_SQL_WCHAR, encoding="utf-8")
+            conn.setencoding(encoding="utf-8")
+
+        return on_connect
+
+
+dialect = MySQLDialect_pyodbc

lib/sqlalchemy/dialects/mysql/reflection.py

@@ -0,0 +1,558 @@
+# mysql/reflection.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+import re
+
+from .enumerated import ENUM
+from .enumerated import SET
+from .types import DATETIME
+from .types import TIME
+from .types import TIMESTAMP
+from ... import log
+from ... import types as sqltypes
+from ... import util
+
+
+class ReflectedState(object):
+    """Stores raw information about a SHOW CREATE TABLE statement."""
+
+    def __init__(self):
+        self.columns = []
+        self.table_options = {}
+        self.table_name = None
+        self.keys = []
+        self.fk_constraints = []
+        self.ck_constraints = []
+
+
+@log.class_logger
+class MySQLTableDefinitionParser(object):
+    """Parses the results of a SHOW CREATE TABLE statement."""
+
+    def __init__(self, dialect, preparer):
+        self.dialect = dialect
+        self.preparer = preparer
+        self._prep_regexes()
+
+    def parse(self, show_create, charset):
+        state = ReflectedState()
+        state.charset = charset
+        for line in re.split(r"\r?\n", show_create):
+            if line.startswith("  " + self.preparer.initial_quote):
+                self._parse_column(line, state)
+            # a regular table options line
+            elif line.startswith(") "):
+                self._parse_table_options(line, state)
+            # an ANSI-mode table options line
+            elif line == ")":
+                pass
+            elif line.startswith("CREATE "):
+                self._parse_table_name(line, state)
+            # Not present in real reflection, but may be if
+            # loading from a file.
+            elif not line:
+                pass
+            else:
+                type_, spec = self._parse_constraints(line)
+                if type_ is None:
+                    util.warn("Unknown schema content: %r" % line)
+                elif type_ == "key":
+                    state.keys.append(spec)
+                elif type_ == "fk_constraint":
+                    state.fk_constraints.append(spec)
+                elif type_ == "ck_constraint":
+                    state.ck_constraints.append(spec)
+                else:
+                    pass
+        return state
+
+    def _parse_constraints(self, line):
+        """Parse a KEY or CONSTRAINT line.
+
+        :param line: A line of SHOW CREATE TABLE output
+        """
+
+        # KEY
+        m = self._re_key.match(line)
+        if m:
+            spec = m.groupdict()
+            # convert columns into name, length pairs
+            # NOTE: we may want to consider SHOW INDEX as the
+            # format of indexes in MySQL becomes more complex
+            spec["columns"] = self._parse_keyexprs(spec["columns"])
+            if spec["version_sql"]:
+                m2 = self._re_key_version_sql.match(spec["version_sql"])
+                if m2 and m2.groupdict()["parser"]:
+                    spec["parser"] = m2.groupdict()["parser"]
+            if spec["parser"]:
+                spec["parser"] = self.preparer.unformat_identifiers(
+                    spec["parser"]
+                )[0]
+            return "key", spec
+
+        # FOREIGN KEY CONSTRAINT
+        m = self._re_fk_constraint.match(line)
+        if m:
+            spec = m.groupdict()
+            spec["table"] = self.preparer.unformat_identifiers(spec["table"])
+            spec["local"] = [c[0] for c in self._parse_keyexprs(spec["local"])]
+            spec["foreign"] = [
+                c[0] for c in self._parse_keyexprs(spec["foreign"])
+            ]
+            return "fk_constraint", spec
+
+        # CHECK constraint
+        m = self._re_ck_constraint.match(line)
+        if m:
+            spec = m.groupdict()
+            return "ck_constraint", spec
+
+        # PARTITION and SUBPARTITION
+        m = self._re_partition.match(line)
+        if m:
+            # Punt!
+            return "partition", line
+
+        # No match.
+        return (None, line)
+
+    def _parse_table_name(self, line, state):
+        """Extract the table name.
+
+        :param line: The first line of SHOW CREATE TABLE
+        """
+
+        regex, cleanup = self._pr_name
+        m = regex.match(line)
+        if m:
+            state.table_name = cleanup(m.group("name"))
+
+    def _parse_table_options(self, line, state):
+        """Build a dictionary of all reflected table-level options.
+
+        :param line: The final line of SHOW CREATE TABLE output.
+        """
+
+        options = {}
+
+        if not line or line == ")":
+            pass
+
+        else:
+            rest_of_line = line[:]
+            for regex, cleanup in self._pr_options:
+                m = regex.search(rest_of_line)
+                if not m:
+                    continue
+                directive, value = m.group("directive"), m.group("val")
+                if cleanup:
+                    value = cleanup(value)
+                options[directive.lower()] = value
+                rest_of_line = regex.sub("", rest_of_line)
+
+        for nope in ("auto_increment", "data directory", "index directory"):
+            options.pop(nope, None)
+
+        for opt, val in options.items():
+            state.table_options["%s_%s" % (self.dialect.name, opt)] = val
+
+    def _parse_column(self, line, state):
+        """Extract column details.
+
+        Falls back to a 'minimal support' variant if full parse fails.
+
+        :param line: Any column-bearing line from SHOW CREATE TABLE
+        """
+
+        spec = None
+        m = self._re_column.match(line)
+        if m:
+            spec = m.groupdict()
+            spec["full"] = True
+        else:
+            m = self._re_column_loose.match(line)
+            if m:
+                spec = m.groupdict()
+                spec["full"] = False
+        if not spec:
+            util.warn("Unknown column definition %r" % line)
+            return
+        if not spec["full"]:
+            util.warn("Incomplete reflection of column definition %r" % line)
+
+        name, type_, args = spec["name"], spec["coltype"], spec["arg"]
+
+        try:
+            col_type = self.dialect.ischema_names[type_]
+        except KeyError:
+            util.warn(
+                "Did not recognize type '%s' of column '%s'" % (type_, name)
+            )
+            col_type = sqltypes.NullType
+
+        # Column type positional arguments eg. varchar(32)
+        if args is None or args == "":
+            type_args = []
+        elif args[0] == "'" and args[-1] == "'":
+            type_args = self._re_csv_str.findall(args)
+        else:
+            type_args = [int(v) for v in self._re_csv_int.findall(args)]
+
+        # Column type keyword options
+        type_kw = {}
+
+        if issubclass(col_type, (DATETIME, TIME, TIMESTAMP)):
+            if type_args:
+                type_kw["fsp"] = type_args.pop(0)
+
+        for kw in ("unsigned", "zerofill"):
+            if spec.get(kw, False):
+                type_kw[kw] = True
+        for kw in ("charset", "collate"):
+            if spec.get(kw, False):
+                type_kw[kw] = spec[kw]
+        if issubclass(col_type, (ENUM, SET)):
+            type_args = _strip_values(type_args)
+
+            if issubclass(col_type, SET) and "" in type_args:
+                type_kw["retrieve_as_bitwise"] = True
+
+        type_instance = col_type(*type_args, **type_kw)
+
+        col_kw = {}
+
+        # NOT NULL
+        col_kw["nullable"] = True
+        # this can be "NULL" in the case of TIMESTAMP
+        if spec.get("notnull", False) == "NOT NULL":
+            col_kw["nullable"] = False
+
+        # AUTO_INCREMENT
+        if spec.get("autoincr", False):
+            col_kw["autoincrement"] = True
+        elif issubclass(col_type, sqltypes.Integer):
+            col_kw["autoincrement"] = False
+
+        # DEFAULT
+        default = spec.get("default", None)
+
+        if default == "NULL":
+            # eliminates the need to deal with this later.
+            default = None
+
+        comment = spec.get("comment", None)
+
+        if comment is not None:
+            comment = comment.replace("\\\\", "\\").replace("''", "'")
+
+        sqltext = spec.get("generated")
+        if sqltext is not None:
+            computed = dict(sqltext=sqltext)
+            persisted = spec.get("persistence")
+            if persisted is not None:
+                computed["persisted"] = persisted == "STORED"
+            col_kw["computed"] = computed
+
+        col_d = dict(
+            name=name, type=type_instance, default=default, comment=comment
+        )
+        col_d.update(col_kw)
+        state.columns.append(col_d)
+
+    def _describe_to_create(self, table_name, columns):
+        """Re-format DESCRIBE output as a SHOW CREATE TABLE string.
+
+        DESCRIBE is a much simpler reflection and is sufficient for
+        reflecting views for runtime use.  This method formats DDL
+        for columns only- keys are omitted.
+
+        :param columns: A sequence of DESCRIBE or SHOW COLUMNS 6-tuples.
+          SHOW FULL COLUMNS FROM rows must be rearranged for use with
+          this function.
+        """
+
+        buffer = []
+        for row in columns:
+            (name, col_type, nullable, default, extra) = [
+                row[i] for i in (0, 1, 2, 4, 5)
+            ]
+
+            line = [" "]
+            line.append(self.preparer.quote_identifier(name))
+            line.append(col_type)
+            if not nullable:
+                line.append("NOT NULL")
+            if default:
+                if "auto_increment" in default:
+                    pass
+                elif col_type.startswith("timestamp") and default.startswith(
+                    "C"
+                ):
+                    line.append("DEFAULT")
+                    line.append(default)
+                elif default == "NULL":
+                    line.append("DEFAULT")
+                    line.append(default)
+                else:
+                    line.append("DEFAULT")
+                    line.append("'%s'" % default.replace("'", "''"))
+            if extra:
+                line.append(extra)
+
+            buffer.append(" ".join(line))
+
+        return "".join(
+            [
+                (
+                    "CREATE TABLE %s (\n"
+                    % self.preparer.quote_identifier(table_name)
+                ),
+                ",\n".join(buffer),
+                "\n) ",
+            ]
+        )
+
+    def _parse_keyexprs(self, identifiers):
+        """Unpack '"col"(2),"col" ASC'-ish strings into components."""
+
+        return self._re_keyexprs.findall(identifiers)
+
+    def _prep_regexes(self):
+        """Pre-compile regular expressions."""
+
+        self._re_columns = []
+        self._pr_options = []
+
+        _final = self.preparer.final_quote
+
+        quotes = dict(
+            zip(
+                ("iq", "fq", "esc_fq"),
+                [
+                    re.escape(s)
+                    for s in (
+                        self.preparer.initial_quote,
+                        _final,
+                        self.preparer._escape_identifier(_final),
+                    )
+                ],
+            )
+        )
+
+        self._pr_name = _pr_compile(
+            r"^CREATE (?:\w+ +)?TABLE +"
+            r"%(iq)s(?P<name>(?:%(esc_fq)s|[^%(fq)s])+)%(fq)s +\($" % quotes,
+            self.preparer._unescape_identifier,
+        )
+
+        # `col`,`col2`(32),`col3`(15) DESC
+        #
+        self._re_keyexprs = _re_compile(
+            r"(?:"
+            r"(?:%(iq)s((?:%(esc_fq)s|[^%(fq)s])+)%(fq)s)"
+            r"(?:\((\d+)\))?(?: +(ASC|DESC))?(?=\,|$))+" % quotes
+        )
+
+        # 'foo' or 'foo','bar' or 'fo,o','ba''a''r'
+        self._re_csv_str = _re_compile(r"\x27(?:\x27\x27|[^\x27])*\x27")
+
+        # 123 or 123,456
+        self._re_csv_int = _re_compile(r"\d+")
+
+        # `colname` <type> [type opts]
+        #  (NOT NULL | NULL)
+        #   DEFAULT ('value' | CURRENT_TIMESTAMP...)
+        #   COMMENT 'comment'
+        #  COLUMN_FORMAT (FIXED|DYNAMIC|DEFAULT)
+        #  STORAGE (DISK|MEMORY)
+        self._re_column = _re_compile(
+            r"  "
+            r"%(iq)s(?P<name>(?:%(esc_fq)s|[^%(fq)s])+)%(fq)s +"
+            r"(?P<coltype>\w+)"
+            r"(?:\((?P<arg>(?:\d+|\d+,\d+|"
+            r"(?:'(?:''|[^'])*',?)+))\))?"
+            r"(?: +(?P<unsigned>UNSIGNED))?"
+            r"(?: +(?P<zerofill>ZEROFILL))?"
+            r"(?: +CHARACTER SET +(?P<charset>[\w_]+))?"
+            r"(?: +COLLATE +(?P<collate>[\w_]+))?"
+            r"(?: +(?P<notnull>(?:NOT )?NULL))?"
+            r"(?: +DEFAULT +(?P<default>"
+            r"(?:NULL|'(?:''|[^'])*'|[\-\w\.\(\)]+"
+            r"(?: +ON UPDATE [\-\w\.\(\)]+)?)"
+            r"))?"
+            r"(?: +(?:GENERATED ALWAYS)? ?AS +(?P<generated>\("
+            r".*\))? ?(?P<persistence>VIRTUAL|STORED)?)?"
+            r"(?: +(?P<autoincr>AUTO_INCREMENT))?"
+            r"(?: +COMMENT +'(?P<comment>(?:''|[^'])*)')?"
+            r"(?: +COLUMN_FORMAT +(?P<colfmt>\w+))?"
+            r"(?: +STORAGE +(?P<storage>\w+))?"
+            r"(?: +(?P<extra>.*))?"
+            r",?$" % quotes
+        )
+
+        # Fallback, try to parse as little as possible
+        self._re_column_loose = _re_compile(
+            r"  "
+            r"%(iq)s(?P<name>(?:%(esc_fq)s|[^%(fq)s])+)%(fq)s +"
+            r"(?P<coltype>\w+)"
+            r"(?:\((?P<arg>(?:\d+|\d+,\d+|\x27(?:\x27\x27|[^\x27])+\x27))\))?"
+            r".*?(?P<notnull>(?:NOT )NULL)?" % quotes
+        )
+
+        # (PRIMARY|UNIQUE|FULLTEXT|SPATIAL) INDEX `name` (USING (BTREE|HASH))?
+        # (`col` (ASC|DESC)?, `col` (ASC|DESC)?)
+        # KEY_BLOCK_SIZE size | WITH PARSER name  /*!50100 WITH PARSER name */
+        self._re_key = _re_compile(
+            r"  "
+            r"(?:(?P<type>\S+) )?KEY"
+            r"(?: +%(iq)s(?P<name>(?:%(esc_fq)s|[^%(fq)s])+)%(fq)s)?"
+            r"(?: +USING +(?P<using_pre>\S+))?"
+            r" +\((?P<columns>.+?)\)"
+            r"(?: +USING +(?P<using_post>\S+))?"
+            r"(?: +KEY_BLOCK_SIZE *[ =]? *(?P<keyblock>\S+))?"
+            r"(?: +WITH PARSER +(?P<parser>\S+))?"
+            r"(?: +COMMENT +(?P<comment>(\x27\x27|\x27([^\x27])*?\x27)+))?"
+            r"(?: +/\*(?P<version_sql>.+)\*/ *)?"
+            r",?$" % quotes
+        )
+
+        # https://forums.mysql.com/read.php?20,567102,567111#msg-567111
+        # It means if the MySQL version >= \d+, execute what's in the comment
+        self._re_key_version_sql = _re_compile(
+            r"\!\d+ " r"(?: *WITH PARSER +(?P<parser>\S+) *)?"
+        )
+
+        # CONSTRAINT `name` FOREIGN KEY (`local_col`)
+        # REFERENCES `remote` (`remote_col`)
+        # MATCH FULL | MATCH PARTIAL | MATCH SIMPLE
+        # ON DELETE CASCADE ON UPDATE RESTRICT
+        #
+        # unique constraints come back as KEYs
+        kw = quotes.copy()
+        kw["on"] = "RESTRICT|CASCADE|SET NULL|NO ACTION"
+        self._re_fk_constraint = _re_compile(
+            r"  "
+            r"CONSTRAINT +"
+            r"%(iq)s(?P<name>(?:%(esc_fq)s|[^%(fq)s])+)%(fq)s +"
+            r"FOREIGN KEY +"
+            r"\((?P<local>[^\)]+?)\) REFERENCES +"
+            r"(?P<table>%(iq)s[^%(fq)s]+%(fq)s"
+            r"(?:\.%(iq)s[^%(fq)s]+%(fq)s)?) +"
+            r"\((?P<foreign>[^\)]+?)\)"
+            r"(?: +(?P<match>MATCH \w+))?"
+            r"(?: +ON DELETE (?P<ondelete>%(on)s))?"
+            r"(?: +ON UPDATE (?P<onupdate>%(on)s))?" % kw
+        )
+
+        # CONSTRAINT `CONSTRAINT_1` CHECK (`x` > 5)'
+        # testing on MariaDB 10.2 shows that the CHECK constraint
+        # is returned on a line by itself, so to match without worrying
+        # about parenthesis in the expression we go to the end of the line
+        self._re_ck_constraint = _re_compile(
+            r"  "
+            r"CONSTRAINT +"
+            r"%(iq)s(?P<name>(?:%(esc_fq)s|[^%(fq)s])+)%(fq)s +"
+            r"CHECK +"
+            r"\((?P<sqltext>.+)\),?" % kw
+        )
+
+        # PARTITION
+        #
+        # punt!
+        self._re_partition = _re_compile(r"(?:.*)(?:SUB)?PARTITION(?:.*)")
+
+        # Table-level options (COLLATE, ENGINE, etc.)
+        # Do the string options first, since they have quoted
+        # strings we need to get rid of.
+        for option in _options_of_type_string:
+            self._add_option_string(option)
+
+        for option in (
+            "ENGINE",
+            "TYPE",
+            "AUTO_INCREMENT",
+            "AVG_ROW_LENGTH",
+            "CHARACTER SET",
+            "DEFAULT CHARSET",
+            "CHECKSUM",
+            "COLLATE",
+            "DELAY_KEY_WRITE",
+            "INSERT_METHOD",
+            "MAX_ROWS",
+            "MIN_ROWS",
+            "PACK_KEYS",
+            "ROW_FORMAT",
+            "KEY_BLOCK_SIZE",
+        ):
+            self._add_option_word(option)
+
+        self._add_option_regex("UNION", r"\([^\)]+\)")
+        self._add_option_regex("TABLESPACE", r".*? STORAGE DISK")
+        self._add_option_regex(
+            "RAID_TYPE",
+            r"\w+\s+RAID_CHUNKS\s*\=\s*\w+RAID_CHUNKSIZE\s*=\s*\w+",
+        )
+
+    _optional_equals = r"(?:\s*(?:=\s*)|\s+)"
+
+    def _add_option_string(self, directive):
+        regex = r"(?P<directive>%s)%s" r"'(?P<val>(?:[^']|'')*?)'(?!')" % (
+            re.escape(directive),
+            self._optional_equals,
+        )
+        self._pr_options.append(
+            _pr_compile(
+                regex, lambda v: v.replace("\\\\", "\\").replace("''", "'")
+            )
+        )
+
+    def _add_option_word(self, directive):
+        regex = r"(?P<directive>%s)%s" r"(?P<val>\w+)" % (
+            re.escape(directive),
+            self._optional_equals,
+        )
+        self._pr_options.append(_pr_compile(regex))
+
+    def _add_option_regex(self, directive, regex):
+        regex = r"(?P<directive>%s)%s" r"(?P<val>%s)" % (
+            re.escape(directive),
+            self._optional_equals,
+            regex,
+        )
+        self._pr_options.append(_pr_compile(regex))
+
+
+_options_of_type_string = (
+    "COMMENT",
+    "DATA DIRECTORY",
+    "INDEX DIRECTORY",
+    "PASSWORD",
+    "CONNECTION",
+)
+
+
+def _pr_compile(regex, cleanup=None):
+    """Prepare a 2-tuple of compiled regex and callable."""
+
+    return (_re_compile(regex), cleanup)
+
+
+def _re_compile(regex):
+    """Compile a string to regex, I and UNICODE."""
+
+    return re.compile(regex, re.I | re.UNICODE)
+
+
+def _strip_values(values):
+    "Strip reflected values quotes"
+    strip_values = []
+    for a in values:
+        if a[0:1] == '"' or a[0:1] == "'":
+            # strip enclosing quotes and unquote interior
+            a = a[1:-1].replace(a[0] * 2, a[0])
+        strip_values.append(a)
+    return strip_values

lib/sqlalchemy/dialects/mysql/reserved_words.py

@@ -0,0 +1,564 @@
+# mysql/reserved_words.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+# generated using:
+# https://gist.github.com/kkirsche/4f31f2153ed7a3248be1ec44ca6ddbc9
+#
+# https://mariadb.com/kb/en/reserved-words/
+# includes: Reserved Words, Oracle Mode (separate set unioned)
+# excludes: Exceptions, Function Names
+RESERVED_WORDS_MARIADB = {
+    "accessible",
+    "add",
+    "all",
+    "alter",
+    "analyze",
+    "and",
+    "as",
+    "asc",
+    "asensitive",
+    "before",
+    "between",
+    "bigint",
+    "binary",
+    "blob",
+    "both",
+    "by",
+    "call",
+    "cascade",
+    "case",
+    "change",
+    "char",
+    "character",
+    "check",
+    "collate",
+    "column",
+    "condition",
+    "constraint",
+    "continue",
+    "convert",
+    "create",
+    "cross",
+    "current_date",
+    "current_role",
+    "current_time",
+    "current_timestamp",
+    "current_user",
+    "cursor",
+    "database",
+    "databases",
+    "day_hour",
+    "day_microsecond",
+    "day_minute",
+    "day_second",
+    "dec",
+    "decimal",
+    "declare",
+    "default",
+    "delayed",
+    "delete",
+    "desc",
+    "describe",
+    "deterministic",
+    "distinct",
+    "distinctrow",
+    "div",
+    "do_domain_ids",
+    "double",
+    "drop",
+    "dual",
+    "each",
+    "else",
+    "elseif",
+    "enclosed",
+    "escaped",
+    "except",
+    "exists",
+    "exit",
+    "explain",
+    "false",
+    "fetch",
+    "float",
+    "float4",
+    "float8",
+    "for",
+    "force",
+    "foreign",
+    "from",
+    "fulltext",
+    "general",
+    "grant",
+    "group",
+    "having",
+    "high_priority",
+    "hour_microsecond",
+    "hour_minute",
+    "hour_second",
+    "if",
+    "ignore",
+    "ignore_domain_ids",
+    "ignore_server_ids",
+    "in",
+    "index",
+    "infile",
+    "inner",
+    "inout",
+    "insensitive",
+    "insert",
+    "int",
+    "int1",
+    "int2",
+    "int3",
+    "int4",
+    "int8",
+    "integer",
+    "intersect",
+    "interval",
+    "into",
+    "is",
+    "iterate",
+    "join",
+    "key",
+    "keys",
+    "kill",
+    "leading",
+    "leave",
+    "left",
+    "like",
+    "limit",
+    "linear",
+    "lines",
+    "load",
+    "localtime",
+    "localtimestamp",
+    "lock",
+    "long",
+    "longblob",
+    "longtext",
+    "loop",
+    "low_priority",
+    "master_heartbeat_period",
+    "master_ssl_verify_server_cert",
+    "match",
+    "maxvalue",
+    "mediumblob",
+    "mediumint",
+    "mediumtext",
+    "middleint",
+    "minute_microsecond",
+    "minute_second",
+    "mod",
+    "modifies",
+    "natural",
+    "no_write_to_binlog",
+    "not",
+    "null",
+    "numeric",
+    "offset",
+    "on",
+    "optimize",
+    "option",
+    "optionally",
+    "or",
+    "order",
+    "out",
+    "outer",
+    "outfile",
+    "over",
+    "page_checksum",
+    "parse_vcol_expr",
+    "partition",
+    "position",
+    "precision",
+    "primary",
+    "procedure",
+    "purge",
+    "range",
+    "read",
+    "read_write",
+    "reads",
+    "real",
+    "recursive",
+    "ref_system_id",
+    "references",
+    "regexp",
+    "release",
+    "rename",
+    "repeat",
+    "replace",
+    "require",
+    "resignal",
+    "restrict",
+    "return",
+    "returning",
+    "revoke",
+    "right",
+    "rlike",
+    "rows",
+    "schema",
+    "schemas",
+    "second_microsecond",
+    "select",
+    "sensitive",
+    "separator",
+    "set",
+    "show",
+    "signal",
+    "slow",
+    "smallint",
+    "spatial",
+    "specific",
+    "sql",
+    "sql_big_result",
+    "sql_calc_found_rows",
+    "sql_small_result",
+    "sqlexception",
+    "sqlstate",
+    "sqlwarning",
+    "ssl",
+    "starting",
+    "stats_auto_recalc",
+    "stats_persistent",
+    "stats_sample_pages",
+    "straight_join",
+    "table",
+    "terminated",
+    "then",
+    "tinyblob",
+    "tinyint",
+    "tinytext",
+    "to",
+    "trailing",
+    "trigger",
+    "true",
+    "undo",
+    "union",
+    "unique",
+    "unlock",
+    "unsigned",
+    "update",
+    "usage",
+    "use",
+    "using",
+    "utc_date",
+    "utc_time",
+    "utc_timestamp",
+    "values",
+    "varbinary",
+    "varchar",
+    "varcharacter",
+    "varying",
+    "when",
+    "where",
+    "while",
+    "window",
+    "with",
+    "write",
+    "xor",
+    "year_month",
+    "zerofill",
+}.union(
+    {
+        "body",
+        "elsif",
+        "goto",
+        "history",
+        "others",
+        "package",
+        "period",
+        "raise",
+        "rowtype",
+        "system",
+        "system_time",
+        "versioning",
+        "without",
+    }
+)
+
+# https://dev.mysql.com/doc/refman/8.0/en/keywords.html
+# https://dev.mysql.com/doc/refman/5.7/en/keywords.html
+# https://dev.mysql.com/doc/refman/5.6/en/keywords.html
+# includes: MySQL x.0 Keywords and Reserved Words
+# excludes: MySQL x.0 New Keywords and Reserved Words,
+#       MySQL x.0 Removed Keywords and Reserved Words
+RESERVED_WORDS_MYSQL = {
+    "accessible",
+    "add",
+    "admin",
+    "all",
+    "alter",
+    "analyze",
+    "and",
+    "array",
+    "as",
+    "asc",
+    "asensitive",
+    "before",
+    "between",
+    "bigint",
+    "binary",
+    "blob",
+    "both",
+    "by",
+    "call",
+    "cascade",
+    "case",
+    "change",
+    "char",
+    "character",
+    "check",
+    "collate",
+    "column",
+    "condition",
+    "constraint",
+    "continue",
+    "convert",
+    "create",
+    "cross",
+    "cube",
+    "cume_dist",
+    "current_date",
+    "current_time",
+    "current_timestamp",
+    "current_user",
+    "cursor",
+    "database",
+    "databases",
+    "day_hour",
+    "day_microsecond",
+    "day_minute",
+    "day_second",
+    "dec",
+    "decimal",
+    "declare",
+    "default",
+    "delayed",
+    "delete",
+    "dense_rank",
+    "desc",
+    "describe",
+    "deterministic",
+    "distinct",
+    "distinctrow",
+    "div",
+    "double",
+    "drop",
+    "dual",
+    "each",
+    "else",
+    "elseif",
+    "empty",
+    "enclosed",
+    "escaped",
+    "except",
+    "exists",
+    "exit",
+    "explain",
+    "false",
+    "fetch",
+    "first_value",
+    "float",
+    "float4",
+    "float8",
+    "for",
+    "force",
+    "foreign",
+    "from",
+    "fulltext",
+    "function",
+    "general",
+    "generated",
+    "get",
+    "get_master_public_key",
+    "grant",
+    "group",
+    "grouping",
+    "groups",
+    "having",
+    "high_priority",
+    "hour_microsecond",
+    "hour_minute",
+    "hour_second",
+    "if",
+    "ignore",
+    "ignore_server_ids",
+    "in",
+    "index",
+    "infile",
+    "inner",
+    "inout",
+    "insensitive",
+    "insert",
+    "int",
+    "int1",
+    "int2",
+    "int3",
+    "int4",
+    "int8",
+    "integer",
+    "interval",
+    "into",
+    "io_after_gtids",
+    "io_before_gtids",
+    "is",
+    "iterate",
+    "join",
+    "json_table",
+    "key",
+    "keys",
+    "kill",
+    "lag",
+    "last_value",
+    "lateral",
+    "lead",
+    "leading",
+    "leave",
+    "left",
+    "like",
+    "limit",
+    "linear",
+    "lines",
+    "load",
+    "localtime",
+    "localtimestamp",
+    "lock",
+    "long",
+    "longblob",
+    "longtext",
+    "loop",
+    "low_priority",
+    "master_bind",
+    "master_heartbeat_period",
+    "master_ssl_verify_server_cert",
+    "match",
+    "maxvalue",
+    "mediumblob",
+    "mediumint",
+    "mediumtext",
+    "member",
+    "middleint",
+    "minute_microsecond",
+    "minute_second",
+    "mod",
+    "modifies",
+    "natural",
+    "no_write_to_binlog",
+    "not",
+    "nth_value",
+    "ntile",
+    "null",
+    "numeric",
+    "of",
+    "on",
+    "optimize",
+    "optimizer_costs",
+    "option",
+    "optionally",
+    "or",
+    "order",
+    "out",
+    "outer",
+    "outfile",
+    "over",
+    "parse_gcol_expr",
+    "partition",
+    "percent_rank",
+    "persist",
+    "persist_only",
+    "precision",
+    "primary",
+    "procedure",
+    "purge",
+    "range",
+    "rank",
+    "read",
+    "read_write",
+    "reads",
+    "real",
+    "recursive",
+    "references",
+    "regexp",
+    "release",
+    "rename",
+    "repeat",
+    "replace",
+    "require",
+    "resignal",
+    "restrict",
+    "return",
+    "revoke",
+    "right",
+    "rlike",
+    "role",
+    "row",
+    "row_number",
+    "rows",
+    "schema",
+    "schemas",
+    "second_microsecond",
+    "select",
+    "sensitive",
+    "separator",
+    "set",
+    "show",
+    "signal",
+    "slow",
+    "smallint",
+    "spatial",
+    "specific",
+    "sql",
+    "sql_after_gtids",
+    "sql_before_gtids",
+    "sql_big_result",
+    "sql_calc_found_rows",
+    "sql_small_result",
+    "sqlexception",
+    "sqlstate",
+    "sqlwarning",
+    "ssl",
+    "starting",
+    "stored",
+    "straight_join",
+    "system",
+    "table",
+    "terminated",
+    "then",
+    "tinyblob",
+    "tinyint",
+    "tinytext",
+    "to",
+    "trailing",
+    "trigger",
+    "true",
+    "undo",
+    "union",
+    "unique",
+    "unlock",
+    "unsigned",
+    "update",
+    "usage",
+    "use",
+    "using",
+    "utc_date",
+    "utc_time",
+    "utc_timestamp",
+    "values",
+    "varbinary",
+    "varchar",
+    "varcharacter",
+    "varying",
+    "virtual",
+    "when",
+    "where",
+    "while",
+    "window",
+    "with",
+    "write",
+    "xor",
+    "year_month",
+    "zerofill",
+}

lib/sqlalchemy/dialects/mysql/types.py

@@ -0,0 +1,773 @@
+# mysql/types.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+import datetime
+
+from ... import exc
+from ... import types as sqltypes
+from ... import util
+
+
+class _NumericType(object):
+    """Base for MySQL numeric types.
+
+    This is the base both for NUMERIC as well as INTEGER, hence
+    it's a mixin.
+
+    """
+
+    def __init__(self, unsigned=False, zerofill=False, **kw):
+        self.unsigned = unsigned
+        self.zerofill = zerofill
+        super(_NumericType, self).__init__(**kw)
+
+    def __repr__(self):
+        return util.generic_repr(
+            self, to_inspect=[_NumericType, sqltypes.Numeric]
+        )
+
+
+class _FloatType(_NumericType, sqltypes.Float):
+    def __init__(self, precision=None, scale=None, asdecimal=True, **kw):
+        if isinstance(self, (REAL, DOUBLE)) and (
+            (precision is None and scale is not None)
+            or (precision is not None and scale is None)
+        ):
+            raise exc.ArgumentError(
+                "You must specify both precision and scale or omit "
+                "both altogether."
+            )
+        super(_FloatType, self).__init__(
+            precision=precision, asdecimal=asdecimal, **kw
+        )
+        self.scale = scale
+
+    def __repr__(self):
+        return util.generic_repr(
+            self, to_inspect=[_FloatType, _NumericType, sqltypes.Float]
+        )
+
+
+class _IntegerType(_NumericType, sqltypes.Integer):
+    def __init__(self, display_width=None, **kw):
+        self.display_width = display_width
+        super(_IntegerType, self).__init__(**kw)
+
+    def __repr__(self):
+        return util.generic_repr(
+            self, to_inspect=[_IntegerType, _NumericType, sqltypes.Integer]
+        )
+
+
+class _StringType(sqltypes.String):
+    """Base for MySQL string types."""
+
+    def __init__(
+        self,
+        charset=None,
+        collation=None,
+        ascii=False,  # noqa
+        binary=False,
+        unicode=False,
+        national=False,
+        **kw
+    ):
+        self.charset = charset
+
+        # allow collate= or collation=
+        kw.setdefault("collation", kw.pop("collate", collation))
+
+        self.ascii = ascii
+        self.unicode = unicode
+        self.binary = binary
+        self.national = national
+        super(_StringType, self).__init__(**kw)
+
+    def __repr__(self):
+        return util.generic_repr(
+            self, to_inspect=[_StringType, sqltypes.String]
+        )
+
+
+class _MatchType(sqltypes.Float, sqltypes.MatchType):
+    def __init__(self, **kw):
+        # TODO: float arguments?
+        sqltypes.Float.__init__(self)
+        sqltypes.MatchType.__init__(self)
+
+
+class NUMERIC(_NumericType, sqltypes.NUMERIC):
+    """MySQL NUMERIC type."""
+
+    __visit_name__ = "NUMERIC"
+
+    def __init__(self, precision=None, scale=None, asdecimal=True, **kw):
+        """Construct a NUMERIC.
+
+        :param precision: Total digits in this number.  If scale and precision
+          are both None, values are stored to limits allowed by the server.
+
+        :param scale: The number of digits after the decimal point.
+
+        :param unsigned: a boolean, optional.
+
+        :param zerofill: Optional. If true, values will be stored as strings
+          left-padded with zeros. Note that this does not effect the values
+          returned by the underlying database API, which continue to be
+          numeric.
+
+        """
+        super(NUMERIC, self).__init__(
+            precision=precision, scale=scale, asdecimal=asdecimal, **kw
+        )
+
+
+class DECIMAL(_NumericType, sqltypes.DECIMAL):
+    """MySQL DECIMAL type."""
+
+    __visit_name__ = "DECIMAL"
+
+    def __init__(self, precision=None, scale=None, asdecimal=True, **kw):
+        """Construct a DECIMAL.
+
+        :param precision: Total digits in this number.  If scale and precision
+          are both None, values are stored to limits allowed by the server.
+
+        :param scale: The number of digits after the decimal point.
+
+        :param unsigned: a boolean, optional.
+
+        :param zerofill: Optional. If true, values will be stored as strings
+          left-padded with zeros. Note that this does not effect the values
+          returned by the underlying database API, which continue to be
+          numeric.
+
+        """
+        super(DECIMAL, self).__init__(
+            precision=precision, scale=scale, asdecimal=asdecimal, **kw
+        )
+
+
+class DOUBLE(_FloatType):
+    """MySQL DOUBLE type."""
+
+    __visit_name__ = "DOUBLE"
+
+    def __init__(self, precision=None, scale=None, asdecimal=True, **kw):
+        """Construct a DOUBLE.
+
+        .. note::
+
+            The :class:`.DOUBLE` type by default converts from float
+            to Decimal, using a truncation that defaults to 10 digits.
+            Specify either ``scale=n`` or ``decimal_return_scale=n`` in order
+            to change this scale, or ``asdecimal=False`` to return values
+            directly as Python floating points.
+
+        :param precision: Total digits in this number.  If scale and precision
+          are both None, values are stored to limits allowed by the server.
+
+        :param scale: The number of digits after the decimal point.
+
+        :param unsigned: a boolean, optional.
+
+        :param zerofill: Optional. If true, values will be stored as strings
+          left-padded with zeros. Note that this does not effect the values
+          returned by the underlying database API, which continue to be
+          numeric.
+
+        """
+        super(DOUBLE, self).__init__(
+            precision=precision, scale=scale, asdecimal=asdecimal, **kw
+        )
+
+
+class REAL(_FloatType, sqltypes.REAL):
+    """MySQL REAL type."""
+
+    __visit_name__ = "REAL"
+
+    def __init__(self, precision=None, scale=None, asdecimal=True, **kw):
+        """Construct a REAL.
+
+        .. note::
+
+            The :class:`.REAL` type by default converts from float
+            to Decimal, using a truncation that defaults to 10 digits.
+            Specify either ``scale=n`` or ``decimal_return_scale=n`` in order
+            to change this scale, or ``asdecimal=False`` to return values
+            directly as Python floating points.
+
+        :param precision: Total digits in this number.  If scale and precision
+          are both None, values are stored to limits allowed by the server.
+
+        :param scale: The number of digits after the decimal point.
+
+        :param unsigned: a boolean, optional.
+
+        :param zerofill: Optional. If true, values will be stored as strings
+          left-padded with zeros. Note that this does not effect the values
+          returned by the underlying database API, which continue to be
+          numeric.
+
+        """
+        super(REAL, self).__init__(
+            precision=precision, scale=scale, asdecimal=asdecimal, **kw
+        )
+
+
+class FLOAT(_FloatType, sqltypes.FLOAT):
+    """MySQL FLOAT type."""
+
+    __visit_name__ = "FLOAT"
+
+    def __init__(self, precision=None, scale=None, asdecimal=False, **kw):
+        """Construct a FLOAT.
+
+        :param precision: Total digits in this number.  If scale and precision
+          are both None, values are stored to limits allowed by the server.
+
+        :param scale: The number of digits after the decimal point.
+
+        :param unsigned: a boolean, optional.
+
+        :param zerofill: Optional. If true, values will be stored as strings
+          left-padded with zeros. Note that this does not effect the values
+          returned by the underlying database API, which continue to be
+          numeric.
+
+        """
+        super(FLOAT, self).__init__(
+            precision=precision, scale=scale, asdecimal=asdecimal, **kw
+        )
+
+    def bind_processor(self, dialect):
+        return None
+
+
+class INTEGER(_IntegerType, sqltypes.INTEGER):
+    """MySQL INTEGER type."""
+
+    __visit_name__ = "INTEGER"
+
+    def __init__(self, display_width=None, **kw):
+        """Construct an INTEGER.
+
+        :param display_width: Optional, maximum display width for this number.
+
+        :param unsigned: a boolean, optional.
+
+        :param zerofill: Optional. If true, values will be stored as strings
+          left-padded with zeros. Note that this does not effect the values
+          returned by the underlying database API, which continue to be
+          numeric.
+
+        """
+        super(INTEGER, self).__init__(display_width=display_width, **kw)
+
+
+class BIGINT(_IntegerType, sqltypes.BIGINT):
+    """MySQL BIGINTEGER type."""
+
+    __visit_name__ = "BIGINT"
+
+    def __init__(self, display_width=None, **kw):
+        """Construct a BIGINTEGER.
+
+        :param display_width: Optional, maximum display width for this number.
+
+        :param unsigned: a boolean, optional.
+
+        :param zerofill: Optional. If true, values will be stored as strings
+          left-padded with zeros. Note that this does not effect the values
+          returned by the underlying database API, which continue to be
+          numeric.
+
+        """
+        super(BIGINT, self).__init__(display_width=display_width, **kw)
+
+
+class MEDIUMINT(_IntegerType):
+    """MySQL MEDIUMINTEGER type."""
+
+    __visit_name__ = "MEDIUMINT"
+
+    def __init__(self, display_width=None, **kw):
+        """Construct a MEDIUMINTEGER
+
+        :param display_width: Optional, maximum display width for this number.
+
+        :param unsigned: a boolean, optional.
+
+        :param zerofill: Optional. If true, values will be stored as strings
+          left-padded with zeros. Note that this does not effect the values
+          returned by the underlying database API, which continue to be
+          numeric.
+
+        """
+        super(MEDIUMINT, self).__init__(display_width=display_width, **kw)
+
+
+class TINYINT(_IntegerType):
+    """MySQL TINYINT type."""
+
+    __visit_name__ = "TINYINT"
+
+    def __init__(self, display_width=None, **kw):
+        """Construct a TINYINT.
+
+        :param display_width: Optional, maximum display width for this number.
+
+        :param unsigned: a boolean, optional.
+
+        :param zerofill: Optional. If true, values will be stored as strings
+          left-padded with zeros. Note that this does not effect the values
+          returned by the underlying database API, which continue to be
+          numeric.
+
+        """
+        super(TINYINT, self).__init__(display_width=display_width, **kw)
+
+
+class SMALLINT(_IntegerType, sqltypes.SMALLINT):
+    """MySQL SMALLINTEGER type."""
+
+    __visit_name__ = "SMALLINT"
+
+    def __init__(self, display_width=None, **kw):
+        """Construct a SMALLINTEGER.
+
+        :param display_width: Optional, maximum display width for this number.
+
+        :param unsigned: a boolean, optional.
+
+        :param zerofill: Optional. If true, values will be stored as strings
+          left-padded with zeros. Note that this does not effect the values
+          returned by the underlying database API, which continue to be
+          numeric.
+
+        """
+        super(SMALLINT, self).__init__(display_width=display_width, **kw)
+
+
+class BIT(sqltypes.TypeEngine):
+    """MySQL BIT type.
+
+    This type is for MySQL 5.0.3 or greater for MyISAM, and 5.0.5 or greater
+    for MyISAM, MEMORY, InnoDB and BDB.  For older versions, use a
+    MSTinyInteger() type.
+
+    """
+
+    __visit_name__ = "BIT"
+
+    def __init__(self, length=None):
+        """Construct a BIT.
+
+        :param length: Optional, number of bits.
+
+        """
+        self.length = length
+
+    def result_processor(self, dialect, coltype):
+        """Convert a MySQL's 64 bit, variable length binary string to a long.
+
+        TODO: this is MySQL-db, pyodbc specific.  OurSQL and mysqlconnector
+        already do this, so this logic should be moved to those dialects.
+
+        """
+
+        def process(value):
+            if value is not None:
+                v = 0
+                for i in value:
+                    if not isinstance(i, int):
+                        i = ord(i)  # convert byte to int on Python 2
+                    v = v << 8 | i
+                return v
+            return value
+
+        return process
+
+
+class TIME(sqltypes.TIME):
+    """MySQL TIME type."""
+
+    __visit_name__ = "TIME"
+
+    def __init__(self, timezone=False, fsp=None):
+        """Construct a MySQL TIME type.
+
+        :param timezone: not used by the MySQL dialect.
+        :param fsp: fractional seconds precision value.
+         MySQL 5.6 supports storage of fractional seconds;
+         this parameter will be used when emitting DDL
+         for the TIME type.
+
+         .. note::
+
+            DBAPI driver support for fractional seconds may
+            be limited; current support includes
+            MySQL Connector/Python.
+
+        """
+        super(TIME, self).__init__(timezone=timezone)
+        self.fsp = fsp
+
+    def result_processor(self, dialect, coltype):
+        time = datetime.time
+
+        def process(value):
+            # convert from a timedelta value
+            if value is not None:
+                microseconds = value.microseconds
+                seconds = value.seconds
+                minutes = seconds // 60
+                return time(
+                    minutes // 60,
+                    minutes % 60,
+                    seconds - minutes * 60,
+                    microsecond=microseconds,
+                )
+            else:
+                return None
+
+        return process
+
+
+class TIMESTAMP(sqltypes.TIMESTAMP):
+    """MySQL TIMESTAMP type."""
+
+    __visit_name__ = "TIMESTAMP"
+
+    def __init__(self, timezone=False, fsp=None):
+        """Construct a MySQL TIMESTAMP type.
+
+        :param timezone: not used by the MySQL dialect.
+        :param fsp: fractional seconds precision value.
+         MySQL 5.6.4 supports storage of fractional seconds;
+         this parameter will be used when emitting DDL
+         for the TIMESTAMP type.
+
+         .. note::
+
+            DBAPI driver support for fractional seconds may
+            be limited; current support includes
+            MySQL Connector/Python.
+
+        """
+        super(TIMESTAMP, self).__init__(timezone=timezone)
+        self.fsp = fsp
+
+
+class DATETIME(sqltypes.DATETIME):
+    """MySQL DATETIME type."""
+
+    __visit_name__ = "DATETIME"
+
+    def __init__(self, timezone=False, fsp=None):
+        """Construct a MySQL DATETIME type.
+
+        :param timezone: not used by the MySQL dialect.
+        :param fsp: fractional seconds precision value.
+         MySQL 5.6.4 supports storage of fractional seconds;
+         this parameter will be used when emitting DDL
+         for the DATETIME type.
+
+         .. note::
+
+            DBAPI driver support for fractional seconds may
+            be limited; current support includes
+            MySQL Connector/Python.
+
+        """
+        super(DATETIME, self).__init__(timezone=timezone)
+        self.fsp = fsp
+
+
+class YEAR(sqltypes.TypeEngine):
+    """MySQL YEAR type, for single byte storage of years 1901-2155."""
+
+    __visit_name__ = "YEAR"
+
+    def __init__(self, display_width=None):
+        self.display_width = display_width
+
+
+class TEXT(_StringType, sqltypes.TEXT):
+    """MySQL TEXT type, for text up to 2^16 characters."""
+
+    __visit_name__ = "TEXT"
+
+    def __init__(self, length=None, **kw):
+        """Construct a TEXT.
+
+        :param length: Optional, if provided the server may optimize storage
+          by substituting the smallest TEXT type sufficient to store
+          ``length`` characters.
+
+        :param charset: Optional, a column-level character set for this string
+          value.  Takes precedence to 'ascii' or 'unicode' short-hand.
+
+        :param collation: Optional, a column-level collation for this string
+          value.  Takes precedence to 'binary' short-hand.
+
+        :param ascii: Defaults to False: short-hand for the ``latin1``
+          character set, generates ASCII in schema.
+
+        :param unicode: Defaults to False: short-hand for the ``ucs2``
+          character set, generates UNICODE in schema.
+
+        :param national: Optional. If true, use the server's configured
+          national character set.
+
+        :param binary: Defaults to False: short-hand, pick the binary
+          collation type that matches the column's character set.  Generates
+          BINARY in schema.  This does not affect the type of data stored,
+          only the collation of character data.
+
+        """
+        super(TEXT, self).__init__(length=length, **kw)
+
+
+class TINYTEXT(_StringType):
+    """MySQL TINYTEXT type, for text up to 2^8 characters."""
+
+    __visit_name__ = "TINYTEXT"
+
+    def __init__(self, **kwargs):
+        """Construct a TINYTEXT.
+
+        :param charset: Optional, a column-level character set for this string
+          value.  Takes precedence to 'ascii' or 'unicode' short-hand.
+
+        :param collation: Optional, a column-level collation for this string
+          value.  Takes precedence to 'binary' short-hand.
+
+        :param ascii: Defaults to False: short-hand for the ``latin1``
+          character set, generates ASCII in schema.
+
+        :param unicode: Defaults to False: short-hand for the ``ucs2``
+          character set, generates UNICODE in schema.
+
+        :param national: Optional. If true, use the server's configured
+          national character set.
+
+        :param binary: Defaults to False: short-hand, pick the binary
+          collation type that matches the column's character set.  Generates
+          BINARY in schema.  This does not affect the type of data stored,
+          only the collation of character data.
+
+        """
+        super(TINYTEXT, self).__init__(**kwargs)
+
+
+class MEDIUMTEXT(_StringType):
+    """MySQL MEDIUMTEXT type, for text up to 2^24 characters."""
+
+    __visit_name__ = "MEDIUMTEXT"
+
+    def __init__(self, **kwargs):
+        """Construct a MEDIUMTEXT.
+
+        :param charset: Optional, a column-level character set for this string
+          value.  Takes precedence to 'ascii' or 'unicode' short-hand.
+
+        :param collation: Optional, a column-level collation for this string
+          value.  Takes precedence to 'binary' short-hand.
+
+        :param ascii: Defaults to False: short-hand for the ``latin1``
+          character set, generates ASCII in schema.
+
+        :param unicode: Defaults to False: short-hand for the ``ucs2``
+          character set, generates UNICODE in schema.
+
+        :param national: Optional. If true, use the server's configured
+          national character set.
+
+        :param binary: Defaults to False: short-hand, pick the binary
+          collation type that matches the column's character set.  Generates
+          BINARY in schema.  This does not affect the type of data stored,
+          only the collation of character data.
+
+        """
+        super(MEDIUMTEXT, self).__init__(**kwargs)
+
+
+class LONGTEXT(_StringType):
+    """MySQL LONGTEXT type, for text up to 2^32 characters."""
+
+    __visit_name__ = "LONGTEXT"
+
+    def __init__(self, **kwargs):
+        """Construct a LONGTEXT.
+
+        :param charset: Optional, a column-level character set for this string
+          value.  Takes precedence to 'ascii' or 'unicode' short-hand.
+
+        :param collation: Optional, a column-level collation for this string
+          value.  Takes precedence to 'binary' short-hand.
+
+        :param ascii: Defaults to False: short-hand for the ``latin1``
+          character set, generates ASCII in schema.
+
+        :param unicode: Defaults to False: short-hand for the ``ucs2``
+          character set, generates UNICODE in schema.
+
+        :param national: Optional. If true, use the server's configured
+          national character set.
+
+        :param binary: Defaults to False: short-hand, pick the binary
+          collation type that matches the column's character set.  Generates
+          BINARY in schema.  This does not affect the type of data stored,
+          only the collation of character data.
+
+        """
+        super(LONGTEXT, self).__init__(**kwargs)
+
+
+class VARCHAR(_StringType, sqltypes.VARCHAR):
+    """MySQL VARCHAR type, for variable-length character data."""
+
+    __visit_name__ = "VARCHAR"
+
+    def __init__(self, length=None, **kwargs):
+        """Construct a VARCHAR.
+
+        :param charset: Optional, a column-level character set for this string
+          value.  Takes precedence to 'ascii' or 'unicode' short-hand.
+
+        :param collation: Optional, a column-level collation for this string
+          value.  Takes precedence to 'binary' short-hand.
+
+        :param ascii: Defaults to False: short-hand for the ``latin1``
+          character set, generates ASCII in schema.
+
+        :param unicode: Defaults to False: short-hand for the ``ucs2``
+          character set, generates UNICODE in schema.
+
+        :param national: Optional. If true, use the server's configured
+          national character set.
+
+        :param binary: Defaults to False: short-hand, pick the binary
+          collation type that matches the column's character set.  Generates
+          BINARY in schema.  This does not affect the type of data stored,
+          only the collation of character data.
+
+        """
+        super(VARCHAR, self).__init__(length=length, **kwargs)
+
+
+class CHAR(_StringType, sqltypes.CHAR):
+    """MySQL CHAR type, for fixed-length character data."""
+
+    __visit_name__ = "CHAR"
+
+    def __init__(self, length=None, **kwargs):
+        """Construct a CHAR.
+
+        :param length: Maximum data length, in characters.
+
+        :param binary: Optional, use the default binary collation for the
+          national character set.  This does not affect the type of data
+          stored, use a BINARY type for binary data.
+
+        :param collation: Optional, request a particular collation.  Must be
+          compatible with the national character set.
+
+        """
+        super(CHAR, self).__init__(length=length, **kwargs)
+
+    @classmethod
+    def _adapt_string_for_cast(self, type_):
+        # copy the given string type into a CHAR
+        # for the purposes of rendering a CAST expression
+        type_ = sqltypes.to_instance(type_)
+        if isinstance(type_, sqltypes.CHAR):
+            return type_
+        elif isinstance(type_, _StringType):
+            return CHAR(
+                length=type_.length,
+                charset=type_.charset,
+                collation=type_.collation,
+                ascii=type_.ascii,
+                binary=type_.binary,
+                unicode=type_.unicode,
+                national=False,  # not supported in CAST
+            )
+        else:
+            return CHAR(length=type_.length)
+
+
+class NVARCHAR(_StringType, sqltypes.NVARCHAR):
+    """MySQL NVARCHAR type.
+
+    For variable-length character data in the server's configured national
+    character set.
+    """
+
+    __visit_name__ = "NVARCHAR"
+
+    def __init__(self, length=None, **kwargs):
+        """Construct an NVARCHAR.
+
+        :param length: Maximum data length, in characters.
+
+        :param binary: Optional, use the default binary collation for the
+          national character set.  This does not affect the type of data
+          stored, use a BINARY type for binary data.
+
+        :param collation: Optional, request a particular collation.  Must be
+          compatible with the national character set.
+
+        """
+        kwargs["national"] = True
+        super(NVARCHAR, self).__init__(length=length, **kwargs)
+
+
+class NCHAR(_StringType, sqltypes.NCHAR):
+    """MySQL NCHAR type.
+
+    For fixed-length character data in the server's configured national
+    character set.
+    """
+
+    __visit_name__ = "NCHAR"
+
+    def __init__(self, length=None, **kwargs):
+        """Construct an NCHAR.
+
+        :param length: Maximum data length, in characters.
+
+        :param binary: Optional, use the default binary collation for the
+          national character set.  This does not affect the type of data
+          stored, use a BINARY type for binary data.
+
+        :param collation: Optional, request a particular collation.  Must be
+          compatible with the national character set.
+
+        """
+        kwargs["national"] = True
+        super(NCHAR, self).__init__(length=length, **kwargs)
+
+
+class TINYBLOB(sqltypes._Binary):
+    """MySQL TINYBLOB type, for binary data up to 2^8 bytes."""
+
+    __visit_name__ = "TINYBLOB"
+
+
+class MEDIUMBLOB(sqltypes._Binary):
+    """MySQL MEDIUMBLOB type, for binary data up to 2^24 bytes."""
+
+    __visit_name__ = "MEDIUMBLOB"
+
+
+class LONGBLOB(sqltypes._Binary):
+    """MySQL LONGBLOB type, for binary data up to 2^32 bytes."""
+
+    __visit_name__ = "LONGBLOB"

lib/sqlalchemy/dialects/oracle/__init__.py

@@ -0,0 +1,58 @@
+# oracle/__init__.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from . import base  # noqa
+from . import cx_oracle  # noqa
+from .base import BFILE
+from .base import BINARY_DOUBLE
+from .base import BINARY_FLOAT
+from .base import BLOB
+from .base import CHAR
+from .base import CLOB
+from .base import DATE
+from .base import DOUBLE_PRECISION
+from .base import FLOAT
+from .base import INTERVAL
+from .base import LONG
+from .base import NCHAR
+from .base import NCLOB
+from .base import NUMBER
+from .base import NVARCHAR
+from .base import NVARCHAR2
+from .base import RAW
+from .base import ROWID
+from .base import TIMESTAMP
+from .base import VARCHAR
+from .base import VARCHAR2
+
+
+base.dialect = dialect = cx_oracle.dialect
+
+__all__ = (
+    "VARCHAR",
+    "NVARCHAR",
+    "CHAR",
+    "NCHAR",
+    "DATE",
+    "NUMBER",
+    "BLOB",
+    "BFILE",
+    "CLOB",
+    "NCLOB",
+    "TIMESTAMP",
+    "RAW",
+    "FLOAT",
+    "DOUBLE_PRECISION",
+    "BINARY_DOUBLE",
+    "BINARY_FLOAT",
+    "LONG",
+    "dialect",
+    "INTERVAL",
+    "VARCHAR2",
+    "NVARCHAR2",
+    "ROWID",
+)

lib/sqlalchemy/dialects/oracle/provision.py

@@ -0,0 +1,160 @@
+from ... import create_engine
+from ... import exc
+from ...engine import url as sa_url
+from ...testing.provision import configure_follower
+from ...testing.provision import create_db
+from ...testing.provision import drop_db
+from ...testing.provision import follower_url_from_main
+from ...testing.provision import log
+from ...testing.provision import post_configure_engine
+from ...testing.provision import run_reap_dbs
+from ...testing.provision import set_default_schema_on_connection
+from ...testing.provision import stop_test_class_outside_fixtures
+from ...testing.provision import temp_table_keyword_args
+
+
+@create_db.for_db("oracle")
+def _oracle_create_db(cfg, eng, ident):
+    # NOTE: make sure you've run "ALTER DATABASE default tablespace users" or
+    # similar, so that the default tablespace is not "system"; reflection will
+    # fail otherwise
+    with eng.begin() as conn:
+        conn.exec_driver_sql("create user %s identified by xe" % ident)
+        conn.exec_driver_sql("create user %s_ts1 identified by xe" % ident)
+        conn.exec_driver_sql("create user %s_ts2 identified by xe" % ident)
+        conn.exec_driver_sql("grant dba to %s" % (ident,))
+        conn.exec_driver_sql("grant unlimited tablespace to %s" % ident)
+        conn.exec_driver_sql("grant unlimited tablespace to %s_ts1" % ident)
+        conn.exec_driver_sql("grant unlimited tablespace to %s_ts2" % ident)
+
+
+@configure_follower.for_db("oracle")
+def _oracle_configure_follower(config, ident):
+    config.test_schema = "%s_ts1" % ident
+    config.test_schema_2 = "%s_ts2" % ident
+
+
+def _ora_drop_ignore(conn, dbname):
+    try:
+        conn.exec_driver_sql("drop user %s cascade" % dbname)
+        log.info("Reaped db: %s", dbname)
+        return True
+    except exc.DatabaseError as err:
+        log.warning("couldn't drop db: %s", err)
+        return False
+
+
+@drop_db.for_db("oracle")
+def _oracle_drop_db(cfg, eng, ident):
+    with eng.begin() as conn:
+        # cx_Oracle seems to occasionally leak open connections when a large
+        # suite it run, even if we confirm we have zero references to
+        # connection objects.
+        # while there is a "kill session" command in Oracle,
+        # it unfortunately does not release the connection sufficiently.
+        _ora_drop_ignore(conn, ident)
+        _ora_drop_ignore(conn, "%s_ts1" % ident)
+        _ora_drop_ignore(conn, "%s_ts2" % ident)
+
+
+@stop_test_class_outside_fixtures.for_db("oracle")
+def stop_test_class_outside_fixtures(config, db, cls):
+
+    try:
+        with db.begin() as conn:
+            # run magic command to get rid of identity sequences
+            # https://floo.bar/2019/11/29/drop-the-underlying-sequence-of-an-identity-column/  # noqa: E501
+            conn.exec_driver_sql("purge recyclebin")
+    except exc.DatabaseError as err:
+        log.warning("purge recyclebin command failed: %s", err)
+
+    # clear statement cache on all connections that were used
+    # https://github.com/oracle/python-cx_Oracle/issues/519
+
+    for cx_oracle_conn in _all_conns:
+        try:
+            sc = cx_oracle_conn.stmtcachesize
+        except db.dialect.dbapi.InterfaceError:
+            # connection closed
+            pass
+        else:
+            cx_oracle_conn.stmtcachesize = 0
+            cx_oracle_conn.stmtcachesize = sc
+    _all_conns.clear()
+
+
+_all_conns = set()
+
+
+@post_configure_engine.for_db("oracle")
+def _oracle_post_configure_engine(url, engine, follower_ident):
+    from sqlalchemy import event
+
+    @event.listens_for(engine, "checkout")
+    def checkout(dbapi_con, con_record, con_proxy):
+        _all_conns.add(dbapi_con)
+
+    @event.listens_for(engine, "checkin")
+    def checkin(dbapi_connection, connection_record):
+        # work around cx_Oracle issue:
+        # https://github.com/oracle/python-cx_Oracle/issues/530
+        # invalidate oracle connections that had 2pc set up
+        if "cx_oracle_xid" in connection_record.info:
+            connection_record.invalidate()
+
+
+@run_reap_dbs.for_db("oracle")
+def _reap_oracle_dbs(url, idents):
+    log.info("db reaper connecting to %r", url)
+    eng = create_engine(url)
+    with eng.begin() as conn:
+
+        log.info("identifiers in file: %s", ", ".join(idents))
+
+        to_reap = conn.exec_driver_sql(
+            "select u.username from all_users u where username "
+            "like 'TEST_%' and not exists (select username "
+            "from v$session where username=u.username)"
+        )
+        all_names = {username.lower() for (username,) in to_reap}
+        to_drop = set()
+        for name in all_names:
+            if name.endswith("_ts1") or name.endswith("_ts2"):
+                continue
+            elif name in idents:
+                to_drop.add(name)
+                if "%s_ts1" % name in all_names:
+                    to_drop.add("%s_ts1" % name)
+                if "%s_ts2" % name in all_names:
+                    to_drop.add("%s_ts2" % name)
+
+        dropped = total = 0
+        for total, username in enumerate(to_drop, 1):
+            if _ora_drop_ignore(conn, username):
+                dropped += 1
+        log.info(
+            "Dropped %d out of %d stale databases detected", dropped, total
+        )
+
+
+@follower_url_from_main.for_db("oracle")
+def _oracle_follower_url_from_main(url, ident):
+    url = sa_url.make_url(url)
+    return url.set(username=ident, password="xe")
+
+
+@temp_table_keyword_args.for_db("oracle")
+def _oracle_temp_table_keyword_args(cfg, eng):
+    return {
+        "prefixes": ["GLOBAL TEMPORARY"],
+        "oracle_on_commit": "PRESERVE ROWS",
+    }
+
+
+@set_default_schema_on_connection.for_db("oracle")
+def _oracle_set_default_schema_on_connection(
+    cfg, dbapi_connection, schema_name
+):
+    cursor = dbapi_connection.cursor()
+    cursor.execute("ALTER SESSION SET CURRENT_SCHEMA=%s" % schema_name)
+    cursor.close()

lib/sqlalchemy/dialects/postgresql/__init__.py

@@ -0,0 +1,117 @@
+# postgresql/__init__.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+from . import base
+from . import pg8000  # noqa
+from . import psycopg2  # noqa
+from . import psycopg2cffi  # noqa
+from . import pygresql  # noqa
+from . import pypostgresql  # noqa
+from .array import All
+from .array import Any
+from .array import ARRAY
+from .array import array
+from .base import BIGINT
+from .base import BIT
+from .base import BOOLEAN
+from .base import BYTEA
+from .base import CHAR
+from .base import CIDR
+from .base import CreateEnumType
+from .base import DATE
+from .base import DOUBLE_PRECISION
+from .base import DropEnumType
+from .base import ENUM
+from .base import FLOAT
+from .base import INET
+from .base import INTEGER
+from .base import INTERVAL
+from .base import MACADDR
+from .base import MONEY
+from .base import NUMERIC
+from .base import OID
+from .base import REAL
+from .base import REGCLASS
+from .base import SMALLINT
+from .base import TEXT
+from .base import TIME
+from .base import TIMESTAMP
+from .base import TSVECTOR
+from .base import UUID
+from .base import VARCHAR
+from .dml import Insert
+from .dml import insert
+from .ext import aggregate_order_by
+from .ext import array_agg
+from .ext import ExcludeConstraint
+from .hstore import HSTORE
+from .hstore import hstore
+from .json import JSON
+from .json import JSONB
+from .ranges import DATERANGE
+from .ranges import INT4RANGE
+from .ranges import INT8RANGE
+from .ranges import NUMRANGE
+from .ranges import TSRANGE
+from .ranges import TSTZRANGE
+from ...util import compat
+
+if compat.py3k:
+    from . import asyncpg  # noqa
+
+base.dialect = dialect = psycopg2.dialect
+
+
+__all__ = (
+    "INTEGER",
+    "BIGINT",
+    "SMALLINT",
+    "VARCHAR",
+    "CHAR",
+    "TEXT",
+    "NUMERIC",
+    "FLOAT",
+    "REAL",
+    "INET",
+    "CIDR",
+    "UUID",
+    "BIT",
+    "MACADDR",
+    "MONEY",
+    "OID",
+    "REGCLASS",
+    "DOUBLE_PRECISION",
+    "TIMESTAMP",
+    "TIME",
+    "DATE",
+    "BYTEA",
+    "BOOLEAN",
+    "INTERVAL",
+    "ARRAY",
+    "ENUM",
+    "dialect",
+    "array",
+    "HSTORE",
+    "hstore",
+    "INT4RANGE",
+    "INT8RANGE",
+    "NUMRANGE",
+    "DATERANGE",
+    "TSVECTOR",
+    "TSRANGE",
+    "TSTZRANGE",
+    "JSON",
+    "JSONB",
+    "Any",
+    "All",
+    "DropEnumType",
+    "CreateEnumType",
+    "ExcludeConstraint",
+    "aggregate_order_by",
+    "array_agg",
+    "insert",
+    "Insert",
+)

lib/sqlalchemy/dialects/postgresql/array.py

@@ -0,0 +1,413 @@
+# postgresql/array.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+import re
+
+from ... import types as sqltypes
+from ... import util
+from ...sql import coercions
+from ...sql import expression
+from ...sql import operators
+from ...sql import roles
+
+
+def Any(other, arrexpr, operator=operators.eq):
+    """A synonym for the ARRAY-level :meth:`.ARRAY.Comparator.any` method.
+    See that method for details.
+
+    """
+
+    return arrexpr.any(other, operator)
+
+
+def All(other, arrexpr, operator=operators.eq):
+    """A synonym for the ARRAY-level :meth:`.ARRAY.Comparator.all` method.
+    See that method for details.
+
+    """
+
+    return arrexpr.all(other, operator)
+
+
+class array(expression.ClauseList, expression.ColumnElement):
+
+    """A PostgreSQL ARRAY literal.
+
+    This is used to produce ARRAY literals in SQL expressions, e.g.::
+
+        from sqlalchemy.dialects.postgresql import array
+        from sqlalchemy.dialects import postgresql
+        from sqlalchemy import select, func
+
+        stmt = select(array([1,2]) + array([3,4,5]))
+
+        print(stmt.compile(dialect=postgresql.dialect()))
+
+    Produces the SQL::
+
+        SELECT ARRAY[%(param_1)s, %(param_2)s] ||
+            ARRAY[%(param_3)s, %(param_4)s, %(param_5)s]) AS anon_1
+
+    An instance of :class:`.array` will always have the datatype
+    :class:`_types.ARRAY`.  The "inner" type of the array is inferred from
+    the values present, unless the ``type_`` keyword argument is passed::
+
+        array(['foo', 'bar'], type_=CHAR)
+
+    Multidimensional arrays are produced by nesting :class:`.array` constructs.
+    The dimensionality of the final :class:`_types.ARRAY`
+    type is calculated by
+    recursively adding the dimensions of the inner :class:`_types.ARRAY`
+    type::
+
+        stmt = select(
+            array([
+                array([1, 2]), array([3, 4]), array([column('q'), column('x')])
+            ])
+        )
+        print(stmt.compile(dialect=postgresql.dialect()))
+
+    Produces::
+
+        SELECT ARRAY[ARRAY[%(param_1)s, %(param_2)s],
+        ARRAY[%(param_3)s, %(param_4)s], ARRAY[q, x]] AS anon_1
+
+    .. versionadded:: 1.3.6 added support for multidimensional array literals
+
+    .. seealso::
+
+        :class:`_postgresql.ARRAY`
+
+    """
+
+    __visit_name__ = "array"
+
+    stringify_dialect = "postgresql"
+    inherit_cache = True
+
+    def __init__(self, clauses, **kw):
+        clauses = [
+            coercions.expect(roles.ExpressionElementRole, c) for c in clauses
+        ]
+
+        super(array, self).__init__(*clauses, **kw)
+
+        self._type_tuple = [arg.type for arg in clauses]
+        main_type = kw.pop(
+            "type_",
+            self._type_tuple[0] if self._type_tuple else sqltypes.NULLTYPE,
+        )
+
+        if isinstance(main_type, ARRAY):
+            self.type = ARRAY(
+                main_type.item_type,
+                dimensions=main_type.dimensions + 1
+                if main_type.dimensions is not None
+                else 2,
+            )
+        else:
+            self.type = ARRAY(main_type)
+
+    @property
+    def _select_iterable(self):
+        return (self,)
+
+    def _bind_param(self, operator, obj, _assume_scalar=False, type_=None):
+        if _assume_scalar or operator is operators.getitem:
+            return expression.BindParameter(
+                None,
+                obj,
+                _compared_to_operator=operator,
+                type_=type_,
+                _compared_to_type=self.type,
+                unique=True,
+            )
+
+        else:
+            return array(
+                [
+                    self._bind_param(
+                        operator, o, _assume_scalar=True, type_=type_
+                    )
+                    for o in obj
+                ]
+            )
+
+    def self_group(self, against=None):
+        if against in (operators.any_op, operators.all_op, operators.getitem):
+            return expression.Grouping(self)
+        else:
+            return self
+
+
+CONTAINS = operators.custom_op("@>", precedence=5, is_comparison=True)
+
+CONTAINED_BY = operators.custom_op("<@", precedence=5, is_comparison=True)
+
+OVERLAP = operators.custom_op("&&", precedence=5, is_comparison=True)
+
+
+class ARRAY(sqltypes.ARRAY):
+
+    """PostgreSQL ARRAY type.
+
+    .. versionchanged:: 1.1 The :class:`_postgresql.ARRAY` type is now
+       a subclass of the core :class:`_types.ARRAY` type.
+
+    The :class:`_postgresql.ARRAY` type is constructed in the same way
+    as the core :class:`_types.ARRAY` type; a member type is required, and a
+    number of dimensions is recommended if the type is to be used for more
+    than one dimension::
+
+        from sqlalchemy.dialects import postgresql
+
+        mytable = Table("mytable", metadata,
+                Column("data", postgresql.ARRAY(Integer, dimensions=2))
+            )
+
+    The :class:`_postgresql.ARRAY` type provides all operations defined on the
+    core :class:`_types.ARRAY` type, including support for "dimensions",
+    indexed access, and simple matching such as
+    :meth:`.types.ARRAY.Comparator.any` and
+    :meth:`.types.ARRAY.Comparator.all`.  :class:`_postgresql.ARRAY`
+    class also
+    provides PostgreSQL-specific methods for containment operations, including
+    :meth:`.postgresql.ARRAY.Comparator.contains`
+    :meth:`.postgresql.ARRAY.Comparator.contained_by`, and
+    :meth:`.postgresql.ARRAY.Comparator.overlap`, e.g.::
+
+        mytable.c.data.contains([1, 2])
+
+    The :class:`_postgresql.ARRAY` type may not be supported on all
+    PostgreSQL DBAPIs; it is currently known to work on psycopg2 only.
+
+    Additionally, the :class:`_postgresql.ARRAY`
+    type does not work directly in
+    conjunction with the :class:`.ENUM` type.  For a workaround, see the
+    special type at :ref:`postgresql_array_of_enum`.
+
+    .. seealso::
+
+        :class:`_types.ARRAY` - base array type
+
+        :class:`_postgresql.array` - produces a literal array value.
+
+    """
+
+    class Comparator(sqltypes.ARRAY.Comparator):
+
+        """Define comparison operations for :class:`_types.ARRAY`.
+
+        Note that these operations are in addition to those provided
+        by the base :class:`.types.ARRAY.Comparator` class, including
+        :meth:`.types.ARRAY.Comparator.any` and
+        :meth:`.types.ARRAY.Comparator.all`.
+
+        """
+
+        def contains(self, other, **kwargs):
+            """Boolean expression.  Test if elements are a superset of the
+            elements of the argument array expression.
+
+            kwargs may be ignored by this operator but are required for API
+            conformance.
+            """
+            return self.operate(CONTAINS, other, result_type=sqltypes.Boolean)
+
+        def contained_by(self, other):
+            """Boolean expression.  Test if elements are a proper subset of the
+            elements of the argument array expression.
+            """
+            return self.operate(
+                CONTAINED_BY, other, result_type=sqltypes.Boolean
+            )
+
+        def overlap(self, other):
+            """Boolean expression.  Test if array has elements in common with
+            an argument array expression.
+            """
+            return self.operate(OVERLAP, other, result_type=sqltypes.Boolean)
+
+    comparator_factory = Comparator
+
+    def __init__(
+        self, item_type, as_tuple=False, dimensions=None, zero_indexes=False
+    ):
+        """Construct an ARRAY.
+
+        E.g.::
+
+          Column('myarray', ARRAY(Integer))
+
+        Arguments are:
+
+        :param item_type: The data type of items of this array. Note that
+          dimensionality is irrelevant here, so multi-dimensional arrays like
+          ``INTEGER[][]``, are constructed as ``ARRAY(Integer)``, not as
+          ``ARRAY(ARRAY(Integer))`` or such.
+
+        :param as_tuple=False: Specify whether return results
+          should be converted to tuples from lists. DBAPIs such
+          as psycopg2 return lists by default. When tuples are
+          returned, the results are hashable.
+
+        :param dimensions: if non-None, the ARRAY will assume a fixed
+         number of dimensions.  This will cause the DDL emitted for this
+         ARRAY to include the exact number of bracket clauses ``[]``,
+         and will also optimize the performance of the type overall.
+         Note that PG arrays are always implicitly "non-dimensioned",
+         meaning they can store any number of dimensions no matter how
+         they were declared.
+
+        :param zero_indexes=False: when True, index values will be converted
+         between Python zero-based and PostgreSQL one-based indexes, e.g.
+         a value of one will be added to all index values before passing
+         to the database.
+
+         .. versionadded:: 0.9.5
+
+
+        """
+        if isinstance(item_type, ARRAY):
+            raise ValueError(
+                "Do not nest ARRAY types; ARRAY(basetype) "
+                "handles multi-dimensional arrays of basetype"
+            )
+        if isinstance(item_type, type):
+            item_type = item_type()
+        self.item_type = item_type
+        self.as_tuple = as_tuple
+        self.dimensions = dimensions
+        self.zero_indexes = zero_indexes
+
+    @property
+    def hashable(self):
+        return self.as_tuple
+
+    @property
+    def python_type(self):
+        return list
+
+    def compare_values(self, x, y):
+        return x == y
+
+    def _proc_array(self, arr, itemproc, dim, collection):
+        if dim is None:
+            arr = list(arr)
+        if (
+            dim == 1
+            or dim is None
+            and (
+                # this has to be (list, tuple), or at least
+                # not hasattr('__iter__'), since Py3K strings
+                # etc. have __iter__
+                not arr
+                or not isinstance(arr[0], (list, tuple))
+            )
+        ):
+            if itemproc:
+                return collection(itemproc(x) for x in arr)
+            else:
+                return collection(arr)
+        else:
+            return collection(
+                self._proc_array(
+                    x,
+                    itemproc,
+                    dim - 1 if dim is not None else None,
+                    collection,
+                )
+                for x in arr
+            )
+
+    @util.memoized_property
+    def _against_native_enum(self):
+        return (
+            isinstance(self.item_type, sqltypes.Enum)
+            and self.item_type.native_enum
+        )
+
+    def bind_expression(self, bindvalue):
+        return bindvalue
+
+    def bind_processor(self, dialect):
+        item_proc = self.item_type.dialect_impl(dialect).bind_processor(
+            dialect
+        )
+
+        def process(value):
+            if value is None:
+                return value
+            else:
+                return self._proc_array(
+                    value, item_proc, self.dimensions, list
+                )
+
+        return process
+
+    def result_processor(self, dialect, coltype):
+        item_proc = self.item_type.dialect_impl(dialect).result_processor(
+            dialect, coltype
+        )
+
+        def process(value):
+            if value is None:
+                return value
+            else:
+                return self._proc_array(
+                    value,
+                    item_proc,
+                    self.dimensions,
+                    tuple if self.as_tuple else list,
+                )
+
+        if self._against_native_enum:
+            super_rp = process
+            pattern = re.compile(r"^{(.*)}$")
+
+            def handle_raw_string(value):
+                inner = pattern.match(value).group(1)
+                return _split_enum_values(inner)
+
+            def process(value):
+                if value is None:
+                    return value
+                # isinstance(value, util.string_types) is required to handle
+                # the case where a TypeDecorator for and Array of Enum is
+                # used like was required in sa < 1.3.17
+                return super_rp(
+                    handle_raw_string(value)
+                    if isinstance(value, util.string_types)
+                    else value
+                )
+
+        return process
+
+
+def _split_enum_values(array_string):
+
+    if '"' not in array_string:
+        # no escape char is present so it can just split on the comma
+        return array_string.split(",") if array_string else []
+
+    # handles quoted strings from:
+    # r'abc,"quoted","also\\\\quoted", "quoted, comma", "esc \" quot", qpr'
+    # returns
+    # ['abc', 'quoted', 'also\\quoted', 'quoted, comma', 'esc " quot', 'qpr']
+    text = array_string.replace(r"\"", "_$ESC_QUOTE$_")
+    text = text.replace(r"\\", "\\")
+    result = []
+    on_quotes = re.split(r'(")', text)
+    in_quotes = False
+    for tok in on_quotes:
+        if tok == '"':
+            in_quotes = not in_quotes
+        elif in_quotes:
+            result.append(tok.replace("_$ESC_QUOTE$_", '"'))
+        else:
+            result.extend(re.findall(r"([^\s,]+),?", tok))
+    return result

lib/sqlalchemy/dialects/postgresql/dml.py

@@ -0,0 +1,274 @@
+# postgresql/on_conflict.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from . import ext
+from ... import util
+from ...sql import coercions
+from ...sql import roles
+from ...sql import schema
+from ...sql.base import _exclusive_against
+from ...sql.base import _generative
+from ...sql.base import ColumnCollection
+from ...sql.dml import Insert as StandardInsert
+from ...sql.elements import ClauseElement
+from ...sql.expression import alias
+from ...util.langhelpers import public_factory
+
+
+__all__ = ("Insert", "insert")
+
+
+class Insert(StandardInsert):
+    """PostgreSQL-specific implementation of INSERT.
+
+    Adds methods for PG-specific syntaxes such as ON CONFLICT.
+
+    The :class:`_postgresql.Insert` object is created using the
+    :func:`sqlalchemy.dialects.postgresql.insert` function.
+
+    .. versionadded:: 1.1
+
+    """
+
+    stringify_dialect = "postgresql"
+    inherit_cache = False
+
+    @util.memoized_property
+    def excluded(self):
+        """Provide the ``excluded`` namespace for an ON CONFLICT statement
+
+        PG's ON CONFLICT clause allows reference to the row that would
+        be inserted, known as ``excluded``.  This attribute provides
+        all columns in this row to be referenceable.
+
+        .. tip::  The :attr:`_postgresql.Insert.excluded` attribute is an
+            instance of :class:`_expression.ColumnCollection`, which provides
+            an interface the same as that of the :attr:`_schema.Table.c`
+            collection described at :ref:`metadata_tables_and_columns`.
+            With this collection, ordinary names are accessible like attributes
+            (e.g. ``stmt.excluded.some_column``), but special names and
+            dictionary method names should be accessed using indexed access,
+            such as ``stmt.excluded["column name"]`` or
+            ``stmt.excluded["values"]``.   See the docstring for
+            :class:`_expression.ColumnCollection` for further examples.
+
+        .. seealso::
+
+            :ref:`postgresql_insert_on_conflict` - example of how
+            to use :attr:`_expression.Insert.excluded`
+
+        """
+        return alias(self.table, name="excluded").columns
+
+    _on_conflict_exclusive = _exclusive_against(
+        "_post_values_clause",
+        msgs={
+            "_post_values_clause": "This Insert construct already has "
+            "an ON CONFLICT clause established"
+        },
+    )
+
+    @_generative
+    @_on_conflict_exclusive
+    def on_conflict_do_update(
+        self,
+        constraint=None,
+        index_elements=None,
+        index_where=None,
+        set_=None,
+        where=None,
+    ):
+        r"""
+        Specifies a DO UPDATE SET action for ON CONFLICT clause.
+
+        Either the ``constraint`` or ``index_elements`` argument is
+        required, but only one of these can be specified.
+
+        :param constraint:
+         The name of a unique or exclusion constraint on the table,
+         or the constraint object itself if it has a .name attribute.
+
+        :param index_elements:
+         A sequence consisting of string column names, :class:`_schema.Column`
+         objects, or other column expression objects that will be used
+         to infer a target index.
+
+        :param index_where:
+         Additional WHERE criterion that can be used to infer a
+         conditional target index.
+
+        :param set\_:
+         A dictionary or other mapping object
+         where the keys are either names of columns in the target table,
+         or :class:`_schema.Column` objects or other ORM-mapped columns
+         matching that of the target table, and expressions or literals
+         as values, specifying the ``SET`` actions to take.
+
+         .. versionadded:: 1.4 The
+            :paramref:`_postgresql.Insert.on_conflict_do_update.set_`
+            parameter supports :class:`_schema.Column` objects from the target
+            :class:`_schema.Table` as keys.
+
+         .. warning:: This dictionary does **not** take into account
+            Python-specified default UPDATE values or generation functions,
+            e.g. those specified using :paramref:`_schema.Column.onupdate`.
+            These values will not be exercised for an ON CONFLICT style of
+            UPDATE, unless they are manually specified in the
+            :paramref:`.Insert.on_conflict_do_update.set_` dictionary.
+
+        :param where:
+         Optional argument. If present, can be a literal SQL
+         string or an acceptable expression for a ``WHERE`` clause
+         that restricts the rows affected by ``DO UPDATE SET``. Rows
+         not meeting the ``WHERE`` condition will not be updated
+         (effectively a ``DO NOTHING`` for those rows).
+
+         .. versionadded:: 1.1
+
+
+        .. seealso::
+
+            :ref:`postgresql_insert_on_conflict`
+
+        """
+        self._post_values_clause = OnConflictDoUpdate(
+            constraint, index_elements, index_where, set_, where
+        )
+
+    @_generative
+    @_on_conflict_exclusive
+    def on_conflict_do_nothing(
+        self, constraint=None, index_elements=None, index_where=None
+    ):
+        """
+        Specifies a DO NOTHING action for ON CONFLICT clause.
+
+        The ``constraint`` and ``index_elements`` arguments
+        are optional, but only one of these can be specified.
+
+        :param constraint:
+         The name of a unique or exclusion constraint on the table,
+         or the constraint object itself if it has a .name attribute.
+
+        :param index_elements:
+         A sequence consisting of string column names, :class:`_schema.Column`
+         objects, or other column expression objects that will be used
+         to infer a target index.
+
+        :param index_where:
+         Additional WHERE criterion that can be used to infer a
+         conditional target index.
+
+         .. versionadded:: 1.1
+
+        .. seealso::
+
+            :ref:`postgresql_insert_on_conflict`
+
+        """
+        self._post_values_clause = OnConflictDoNothing(
+            constraint, index_elements, index_where
+        )
+
+
+insert = public_factory(
+    Insert, ".dialects.postgresql.insert", ".dialects.postgresql.Insert"
+)
+
+
+class OnConflictClause(ClauseElement):
+    stringify_dialect = "postgresql"
+
+    def __init__(self, constraint=None, index_elements=None, index_where=None):
+
+        if constraint is not None:
+            if not isinstance(constraint, util.string_types) and isinstance(
+                constraint,
+                (schema.Index, schema.Constraint, ext.ExcludeConstraint),
+            ):
+                constraint = getattr(constraint, "name") or constraint
+
+        if constraint is not None:
+            if index_elements is not None:
+                raise ValueError(
+                    "'constraint' and 'index_elements' are mutually exclusive"
+                )
+
+            if isinstance(constraint, util.string_types):
+                self.constraint_target = constraint
+                self.inferred_target_elements = None
+                self.inferred_target_whereclause = None
+            elif isinstance(constraint, schema.Index):
+                index_elements = constraint.expressions
+                index_where = constraint.dialect_options["postgresql"].get(
+                    "where"
+                )
+            elif isinstance(constraint, ext.ExcludeConstraint):
+                index_elements = constraint.columns
+                index_where = constraint.where
+            else:
+                index_elements = constraint.columns
+                index_where = constraint.dialect_options["postgresql"].get(
+                    "where"
+                )
+
+        if index_elements is not None:
+            self.constraint_target = None
+            self.inferred_target_elements = index_elements
+            self.inferred_target_whereclause = index_where
+        elif constraint is None:
+            self.constraint_target = (
+                self.inferred_target_elements
+            ) = self.inferred_target_whereclause = None
+
+
+class OnConflictDoNothing(OnConflictClause):
+    __visit_name__ = "on_conflict_do_nothing"
+
+
+class OnConflictDoUpdate(OnConflictClause):
+    __visit_name__ = "on_conflict_do_update"
+
+    def __init__(
+        self,
+        constraint=None,
+        index_elements=None,
+        index_where=None,
+        set_=None,
+        where=None,
+    ):
+        super(OnConflictDoUpdate, self).__init__(
+            constraint=constraint,
+            index_elements=index_elements,
+            index_where=index_where,
+        )
+
+        if (
+            self.inferred_target_elements is None
+            and self.constraint_target is None
+        ):
+            raise ValueError(
+                "Either constraint or index_elements, "
+                "but not both, must be specified unless DO NOTHING"
+            )
+
+        if isinstance(set_, dict):
+            if not set_:
+                raise ValueError("set parameter dictionary must not be empty")
+        elif isinstance(set_, ColumnCollection):
+            set_ = dict(set_)
+        else:
+            raise ValueError(
+                "set parameter must be a non-empty dictionary "
+                "or a ColumnCollection such as the `.c.` collection "
+                "of a Table object"
+            )
+        self.update_values_to_set = [
+            (coercions.expect(roles.DMLColumnRole, key), value)
+            for key, value in set_.items()
+        ]
+        self.update_whereclause = where

lib/sqlalchemy/dialects/postgresql/ext.py

@@ -0,0 +1,277 @@
+# postgresql/ext.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from .array import ARRAY
+from ... import util
+from ...sql import coercions
+from ...sql import elements
+from ...sql import expression
+from ...sql import functions
+from ...sql import roles
+from ...sql import schema
+from ...sql.schema import ColumnCollectionConstraint
+
+
+class aggregate_order_by(expression.ColumnElement):
+    """Represent a PostgreSQL aggregate order by expression.
+
+    E.g.::
+
+        from sqlalchemy.dialects.postgresql import aggregate_order_by
+        expr = func.array_agg(aggregate_order_by(table.c.a, table.c.b.desc()))
+        stmt = select(expr)
+
+    would represent the expression::
+
+        SELECT array_agg(a ORDER BY b DESC) FROM table;
+
+    Similarly::
+
+        expr = func.string_agg(
+            table.c.a,
+            aggregate_order_by(literal_column("','"), table.c.a)
+        )
+        stmt = select(expr)
+
+    Would represent::
+
+        SELECT string_agg(a, ',' ORDER BY a) FROM table;
+
+    .. versionadded:: 1.1
+
+    .. versionchanged:: 1.2.13 - the ORDER BY argument may be multiple terms
+
+    .. seealso::
+
+        :class:`_functions.array_agg`
+
+    """
+
+    __visit_name__ = "aggregate_order_by"
+
+    stringify_dialect = "postgresql"
+    inherit_cache = False
+
+    def __init__(self, target, *order_by):
+        self.target = coercions.expect(roles.ExpressionElementRole, target)
+        self.type = self.target.type
+
+        _lob = len(order_by)
+        if _lob == 0:
+            raise TypeError("at least one ORDER BY element is required")
+        elif _lob == 1:
+            self.order_by = coercions.expect(
+                roles.ExpressionElementRole, order_by[0]
+            )
+        else:
+            self.order_by = elements.ClauseList(
+                *order_by, _literal_as_text_role=roles.ExpressionElementRole
+            )
+
+    def self_group(self, against=None):
+        return self
+
+    def get_children(self, **kwargs):
+        return self.target, self.order_by
+
+    def _copy_internals(self, clone=elements._clone, **kw):
+        self.target = clone(self.target, **kw)
+        self.order_by = clone(self.order_by, **kw)
+
+    @property
+    def _from_objects(self):
+        return self.target._from_objects + self.order_by._from_objects
+
+
+class ExcludeConstraint(ColumnCollectionConstraint):
+    """A table-level EXCLUDE constraint.
+
+    Defines an EXCLUDE constraint as described in the `PostgreSQL
+    documentation`__.
+
+    __ https://www.postgresql.org/docs/current/static/sql-createtable.html#SQL-CREATETABLE-EXCLUDE
+
+    """  # noqa
+
+    __visit_name__ = "exclude_constraint"
+
+    where = None
+    inherit_cache = False
+
+    create_drop_stringify_dialect = "postgresql"
+
+    @elements._document_text_coercion(
+        "where",
+        ":class:`.ExcludeConstraint`",
+        ":paramref:`.ExcludeConstraint.where`",
+    )
+    def __init__(self, *elements, **kw):
+        r"""
+        Create an :class:`.ExcludeConstraint` object.
+
+        E.g.::
+
+            const = ExcludeConstraint(
+                (Column('period'), '&&'),
+                (Column('group'), '='),
+                where=(Column('group') != 'some group'),
+                ops={'group': 'my_operator_class'}
+            )
+
+        The constraint is normally embedded into the :class:`_schema.Table`
+        construct
+        directly, or added later using :meth:`.append_constraint`::
+
+            some_table = Table(
+                'some_table', metadata,
+                Column('id', Integer, primary_key=True),
+                Column('period', TSRANGE()),
+                Column('group', String)
+            )
+
+            some_table.append_constraint(
+                ExcludeConstraint(
+                    (some_table.c.period, '&&'),
+                    (some_table.c.group, '='),
+                    where=some_table.c.group != 'some group',
+                    name='some_table_excl_const',
+                    ops={'group': 'my_operator_class'}
+                )
+            )
+
+        :param \*elements:
+
+          A sequence of two tuples of the form ``(column, operator)`` where
+          "column" is a SQL expression element or a raw SQL string, most
+          typically a :class:`_schema.Column` object,
+          and "operator" is a string
+          containing the operator to use.   In order to specify a column name
+          when a  :class:`_schema.Column` object is not available,
+          while ensuring
+          that any necessary quoting rules take effect, an ad-hoc
+          :class:`_schema.Column` or :func:`_expression.column`
+          object should be
+          used.
+
+        :param name:
+          Optional, the in-database name of this constraint.
+
+        :param deferrable:
+          Optional bool.  If set, emit DEFERRABLE or NOT DEFERRABLE when
+          issuing DDL for this constraint.
+
+        :param initially:
+          Optional string.  If set, emit INITIALLY <value> when issuing DDL
+          for this constraint.
+
+        :param using:
+          Optional string.  If set, emit USING <index_method> when issuing DDL
+          for this constraint. Defaults to 'gist'.
+
+        :param where:
+          Optional SQL expression construct or literal SQL string.
+          If set, emit WHERE <predicate> when issuing DDL
+          for this constraint.
+
+        :param ops:
+          Optional dictionary.  Used to define operator classes for the
+          elements; works the same way as that of the
+          :ref:`postgresql_ops <postgresql_operator_classes>`
+          parameter specified to the :class:`_schema.Index` construct.
+
+          .. versionadded:: 1.3.21
+
+          .. seealso::
+
+            :ref:`postgresql_operator_classes` - general description of how
+            PostgreSQL operator classes are specified.
+
+        """
+        columns = []
+        render_exprs = []
+        self.operators = {}
+
+        expressions, operators = zip(*elements)
+
+        for (expr, column, strname, add_element), operator in zip(
+            coercions.expect_col_expression_collection(
+                roles.DDLConstraintColumnRole, expressions
+            ),
+            operators,
+        ):
+            if add_element is not None:
+                columns.append(add_element)
+
+            name = column.name if column is not None else strname
+
+            if name is not None:
+                # backwards compat
+                self.operators[name] = operator
+
+            render_exprs.append((expr, name, operator))
+
+        self._render_exprs = render_exprs
+
+        ColumnCollectionConstraint.__init__(
+            self,
+            *columns,
+            name=kw.get("name"),
+            deferrable=kw.get("deferrable"),
+            initially=kw.get("initially")
+        )
+        self.using = kw.get("using", "gist")
+        where = kw.get("where")
+        if where is not None:
+            self.where = coercions.expect(roles.StatementOptionRole, where)
+
+        self.ops = kw.get("ops", {})
+
+    def _set_parent(self, table, **kw):
+        super(ExcludeConstraint, self)._set_parent(table)
+
+        self._render_exprs = [
+            (
+                expr if isinstance(expr, elements.ClauseElement) else colexpr,
+                name,
+                operator,
+            )
+            for (expr, name, operator), colexpr in util.zip_longest(
+                self._render_exprs, self.columns
+            )
+        ]
+
+    def _copy(self, target_table=None, **kw):
+        elements = [
+            (
+                schema._copy_expression(expr, self.parent, target_table),
+                self.operators[expr.name],
+            )
+            for expr in self.columns
+        ]
+        c = self.__class__(
+            *elements,
+            name=self.name,
+            deferrable=self.deferrable,
+            initially=self.initially,
+            where=self.where,
+            using=self.using
+        )
+        c.dispatch._update(self.dispatch)
+        return c
+
+
+def array_agg(*arg, **kw):
+    """PostgreSQL-specific form of :class:`_functions.array_agg`, ensures
+    return type is :class:`_postgresql.ARRAY` and not
+    the plain :class:`_types.ARRAY`, unless an explicit ``type_``
+    is passed.
+
+    .. versionadded:: 1.1
+
+    """
+    kw["_default_array_type"] = ARRAY
+    return functions.func.array_agg(*arg, **kw)

lib/sqlalchemy/dialects/postgresql/hstore.py

@@ -0,0 +1,455 @@
+# postgresql/hstore.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+import re
+
+from .array import ARRAY
+from ... import types as sqltypes
+from ... import util
+from ...sql import functions as sqlfunc
+from ...sql import operators
+
+
+__all__ = ("HSTORE", "hstore")
+
+idx_precedence = operators._PRECEDENCE[operators.json_getitem_op]
+
+GETITEM = operators.custom_op(
+    "->",
+    precedence=idx_precedence,
+    natural_self_precedent=True,
+    eager_grouping=True,
+)
+
+HAS_KEY = operators.custom_op(
+    "?",
+    precedence=idx_precedence,
+    natural_self_precedent=True,
+    eager_grouping=True,
+)
+
+HAS_ALL = operators.custom_op(
+    "?&",
+    precedence=idx_precedence,
+    natural_self_precedent=True,
+    eager_grouping=True,
+)
+
+HAS_ANY = operators.custom_op(
+    "?|",
+    precedence=idx_precedence,
+    natural_self_precedent=True,
+    eager_grouping=True,
+)
+
+CONTAINS = operators.custom_op(
+    "@>",
+    precedence=idx_precedence,
+    natural_self_precedent=True,
+    eager_grouping=True,
+)
+
+CONTAINED_BY = operators.custom_op(
+    "<@",
+    precedence=idx_precedence,
+    natural_self_precedent=True,
+    eager_grouping=True,
+)
+
+
+class HSTORE(sqltypes.Indexable, sqltypes.Concatenable, sqltypes.TypeEngine):
+    """Represent the PostgreSQL HSTORE type.
+
+    The :class:`.HSTORE` type stores dictionaries containing strings, e.g.::
+
+        data_table = Table('data_table', metadata,
+            Column('id', Integer, primary_key=True),
+            Column('data', HSTORE)
+        )
+
+        with engine.connect() as conn:
+            conn.execute(
+                data_table.insert(),
+                data = {"key1": "value1", "key2": "value2"}
+            )
+
+    :class:`.HSTORE` provides for a wide range of operations, including:
+
+    * Index operations::
+
+        data_table.c.data['some key'] == 'some value'
+
+    * Containment operations::
+
+        data_table.c.data.has_key('some key')
+
+        data_table.c.data.has_all(['one', 'two', 'three'])
+
+    * Concatenation::
+
+        data_table.c.data + {"k1": "v1"}
+
+    For a full list of special methods see
+    :class:`.HSTORE.comparator_factory`.
+
+    For usage with the SQLAlchemy ORM, it may be desirable to combine
+    the usage of :class:`.HSTORE` with :class:`.MutableDict` dictionary
+    now part of the :mod:`sqlalchemy.ext.mutable`
+    extension.  This extension will allow "in-place" changes to the
+    dictionary, e.g. addition of new keys or replacement/removal of existing
+    keys to/from the current dictionary, to produce events which will be
+    detected by the unit of work::
+
+        from sqlalchemy.ext.mutable import MutableDict
+
+        class MyClass(Base):
+            __tablename__ = 'data_table'
+
+            id = Column(Integer, primary_key=True)
+            data = Column(MutableDict.as_mutable(HSTORE))
+
+        my_object = session.query(MyClass).one()
+
+        # in-place mutation, requires Mutable extension
+        # in order for the ORM to detect
+        my_object.data['some_key'] = 'some value'
+
+        session.commit()
+
+    When the :mod:`sqlalchemy.ext.mutable` extension is not used, the ORM
+    will not be alerted to any changes to the contents of an existing
+    dictionary, unless that dictionary value is re-assigned to the
+    HSTORE-attribute itself, thus generating a change event.
+
+    .. seealso::
+
+        :class:`.hstore` - render the PostgreSQL ``hstore()`` function.
+
+
+    """
+
+    __visit_name__ = "HSTORE"
+    hashable = False
+    text_type = sqltypes.Text()
+
+    def __init__(self, text_type=None):
+        """Construct a new :class:`.HSTORE`.
+
+        :param text_type: the type that should be used for indexed values.
+         Defaults to :class:`_types.Text`.
+
+         .. versionadded:: 1.1.0
+
+        """
+        if text_type is not None:
+            self.text_type = text_type
+
+    class Comparator(
+        sqltypes.Indexable.Comparator, sqltypes.Concatenable.Comparator
+    ):
+        """Define comparison operations for :class:`.HSTORE`."""
+
+        def has_key(self, other):
+            """Boolean expression.  Test for presence of a key.  Note that the
+            key may be a SQLA expression.
+            """
+            return self.operate(HAS_KEY, other, result_type=sqltypes.Boolean)
+
+        def has_all(self, other):
+            """Boolean expression.  Test for presence of all keys in jsonb"""
+            return self.operate(HAS_ALL, other, result_type=sqltypes.Boolean)
+
+        def has_any(self, other):
+            """Boolean expression.  Test for presence of any key in jsonb"""
+            return self.operate(HAS_ANY, other, result_type=sqltypes.Boolean)
+
+        def contains(self, other, **kwargs):
+            """Boolean expression.  Test if keys (or array) are a superset
+            of/contained the keys of the argument jsonb expression.
+
+            kwargs may be ignored by this operator but are required for API
+            conformance.
+            """
+            return self.operate(CONTAINS, other, result_type=sqltypes.Boolean)
+
+        def contained_by(self, other):
+            """Boolean expression.  Test if keys are a proper subset of the
+            keys of the argument jsonb expression.
+            """
+            return self.operate(
+                CONTAINED_BY, other, result_type=sqltypes.Boolean
+            )
+
+        def _setup_getitem(self, index):
+            return GETITEM, index, self.type.text_type
+
+        def defined(self, key):
+            """Boolean expression.  Test for presence of a non-NULL value for
+            the key.  Note that the key may be a SQLA expression.
+            """
+            return _HStoreDefinedFunction(self.expr, key)
+
+        def delete(self, key):
+            """HStore expression.  Returns the contents of this hstore with the
+            given key deleted.  Note that the key may be a SQLA expression.
+            """
+            if isinstance(key, dict):
+                key = _serialize_hstore(key)
+            return _HStoreDeleteFunction(self.expr, key)
+
+        def slice(self, array):
+            """HStore expression.  Returns a subset of an hstore defined by
+            array of keys.
+            """
+            return _HStoreSliceFunction(self.expr, array)
+
+        def keys(self):
+            """Text array expression.  Returns array of keys."""
+            return _HStoreKeysFunction(self.expr)
+
+        def vals(self):
+            """Text array expression.  Returns array of values."""
+            return _HStoreValsFunction(self.expr)
+
+        def array(self):
+            """Text array expression.  Returns array of alternating keys and
+            values.
+            """
+            return _HStoreArrayFunction(self.expr)
+
+        def matrix(self):
+            """Text array expression.  Returns array of [key, value] pairs."""
+            return _HStoreMatrixFunction(self.expr)
+
+    comparator_factory = Comparator
+
+    def bind_processor(self, dialect):
+        if util.py2k:
+            encoding = dialect.encoding
+
+            def process(value):
+                if isinstance(value, dict):
+                    return _serialize_hstore(value).encode(encoding)
+                else:
+                    return value
+
+        else:
+
+            def process(value):
+                if isinstance(value, dict):
+                    return _serialize_hstore(value)
+                else:
+                    return value
+
+        return process
+
+    def result_processor(self, dialect, coltype):
+        if util.py2k:
+            encoding = dialect.encoding
+
+            def process(value):
+                if value is not None:
+                    return _parse_hstore(value.decode(encoding))
+                else:
+                    return value
+
+        else:
+
+            def process(value):
+                if value is not None:
+                    return _parse_hstore(value)
+                else:
+                    return value
+
+        return process
+
+
+class hstore(sqlfunc.GenericFunction):
+    """Construct an hstore value within a SQL expression using the
+    PostgreSQL ``hstore()`` function.
+
+    The :class:`.hstore` function accepts one or two arguments as described
+    in the PostgreSQL documentation.
+
+    E.g.::
+
+        from sqlalchemy.dialects.postgresql import array, hstore
+
+        select(hstore('key1', 'value1'))
+
+        select(
+            hstore(
+                array(['key1', 'key2', 'key3']),
+                array(['value1', 'value2', 'value3'])
+            )
+        )
+
+    .. seealso::
+
+        :class:`.HSTORE` - the PostgreSQL ``HSTORE`` datatype.
+
+    """
+
+    type = HSTORE
+    name = "hstore"
+    inherit_cache = True
+
+
+class _HStoreDefinedFunction(sqlfunc.GenericFunction):
+    type = sqltypes.Boolean
+    name = "defined"
+    inherit_cache = True
+
+
+class _HStoreDeleteFunction(sqlfunc.GenericFunction):
+    type = HSTORE
+    name = "delete"
+    inherit_cache = True
+
+
+class _HStoreSliceFunction(sqlfunc.GenericFunction):
+    type = HSTORE
+    name = "slice"
+    inherit_cache = True
+
+
+class _HStoreKeysFunction(sqlfunc.GenericFunction):
+    type = ARRAY(sqltypes.Text)
+    name = "akeys"
+    inherit_cache = True
+
+
+class _HStoreValsFunction(sqlfunc.GenericFunction):
+    type = ARRAY(sqltypes.Text)
+    name = "avals"
+    inherit_cache = True
+
+
+class _HStoreArrayFunction(sqlfunc.GenericFunction):
+    type = ARRAY(sqltypes.Text)
+    name = "hstore_to_array"
+    inherit_cache = True
+
+
+class _HStoreMatrixFunction(sqlfunc.GenericFunction):
+    type = ARRAY(sqltypes.Text)
+    name = "hstore_to_matrix"
+    inherit_cache = True
+
+
+#
+# parsing.  note that none of this is used with the psycopg2 backend,
+# which provides its own native extensions.
+#
+
+# My best guess at the parsing rules of hstore literals, since no formal
+# grammar is given.  This is mostly reverse engineered from PG's input parser
+# behavior.
+HSTORE_PAIR_RE = re.compile(
+    r"""
+(
+  "(?P<key> (\\ . | [^"])* )"       # Quoted key
+)
+[ ]* => [ ]*    # Pair operator, optional adjoining whitespace
+(
+    (?P<value_null> NULL )          # NULL value
+  | "(?P<value> (\\ . | [^"])* )"   # Quoted value
+)
+""",
+    re.VERBOSE,
+)
+
+HSTORE_DELIMITER_RE = re.compile(
+    r"""
+[ ]* , [ ]*
+""",
+    re.VERBOSE,
+)
+
+
+def _parse_error(hstore_str, pos):
+    """format an unmarshalling error."""
+
+    ctx = 20
+    hslen = len(hstore_str)
+
+    parsed_tail = hstore_str[max(pos - ctx - 1, 0) : min(pos, hslen)]
+    residual = hstore_str[min(pos, hslen) : min(pos + ctx + 1, hslen)]
+
+    if len(parsed_tail) > ctx:
+        parsed_tail = "[...]" + parsed_tail[1:]
+    if len(residual) > ctx:
+        residual = residual[:-1] + "[...]"
+
+    return "After %r, could not parse residual at position %d: %r" % (
+        parsed_tail,
+        pos,
+        residual,
+    )
+
+
+def _parse_hstore(hstore_str):
+    """Parse an hstore from its literal string representation.
+
+    Attempts to approximate PG's hstore input parsing rules as closely as
+    possible. Although currently this is not strictly necessary, since the
+    current implementation of hstore's output syntax is stricter than what it
+    accepts as input, the documentation makes no guarantees that will always
+    be the case.
+
+
+
+    """
+    result = {}
+    pos = 0
+    pair_match = HSTORE_PAIR_RE.match(hstore_str)
+
+    while pair_match is not None:
+        key = pair_match.group("key").replace(r"\"", '"').replace("\\\\", "\\")
+        if pair_match.group("value_null"):
+            value = None
+        else:
+            value = (
+                pair_match.group("value")
+                .replace(r"\"", '"')
+                .replace("\\\\", "\\")
+            )
+        result[key] = value
+
+        pos += pair_match.end()
+
+        delim_match = HSTORE_DELIMITER_RE.match(hstore_str[pos:])
+        if delim_match is not None:
+            pos += delim_match.end()
+
+        pair_match = HSTORE_PAIR_RE.match(hstore_str[pos:])
+
+    if pos != len(hstore_str):
+        raise ValueError(_parse_error(hstore_str, pos))
+
+    return result
+
+
+def _serialize_hstore(val):
+    """Serialize a dictionary into an hstore literal.  Keys and values must
+    both be strings (except None for values).
+
+    """
+
+    def esc(s, position):
+        if position == "value" and s is None:
+            return "NULL"
+        elif isinstance(s, util.string_types):
+            return '"%s"' % s.replace("\\", "\\\\").replace('"', r"\"")
+        else:
+            raise ValueError(
+                "%r in %s position is not a string." % (s, position)
+            )
+
+    return ", ".join(
+        "%s=>%s" % (esc(k, "key"), esc(v, "value")) for k, v in val.items()
+    )

lib/sqlalchemy/dialects/postgresql/json.py

@@ -0,0 +1,327 @@
+# postgresql/json.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+from __future__ import absolute_import
+
+from ... import types as sqltypes
+from ... import util
+from ...sql import operators
+
+
+__all__ = ("JSON", "JSONB")
+
+idx_precedence = operators._PRECEDENCE[operators.json_getitem_op]
+
+ASTEXT = operators.custom_op(
+    "->>",
+    precedence=idx_precedence,
+    natural_self_precedent=True,
+    eager_grouping=True,
+)
+
+JSONPATH_ASTEXT = operators.custom_op(
+    "#>>",
+    precedence=idx_precedence,
+    natural_self_precedent=True,
+    eager_grouping=True,
+)
+
+
+HAS_KEY = operators.custom_op(
+    "?",
+    precedence=idx_precedence,
+    natural_self_precedent=True,
+    eager_grouping=True,
+)
+
+HAS_ALL = operators.custom_op(
+    "?&",
+    precedence=idx_precedence,
+    natural_self_precedent=True,
+    eager_grouping=True,
+)
+
+HAS_ANY = operators.custom_op(
+    "?|",
+    precedence=idx_precedence,
+    natural_self_precedent=True,
+    eager_grouping=True,
+)
+
+CONTAINS = operators.custom_op(
+    "@>",
+    precedence=idx_precedence,
+    natural_self_precedent=True,
+    eager_grouping=True,
+)
+
+CONTAINED_BY = operators.custom_op(
+    "<@",
+    precedence=idx_precedence,
+    natural_self_precedent=True,
+    eager_grouping=True,
+)
+
+
+class JSONPathType(sqltypes.JSON.JSONPathType):
+    def bind_processor(self, dialect):
+        super_proc = self.string_bind_processor(dialect)
+
+        def process(value):
+            assert isinstance(value, util.collections_abc.Sequence)
+            tokens = [util.text_type(elem) for elem in value]
+            value = "{%s}" % (", ".join(tokens))
+            if super_proc:
+                value = super_proc(value)
+            return value
+
+        return process
+
+    def literal_processor(self, dialect):
+        super_proc = self.string_literal_processor(dialect)
+
+        def process(value):
+            assert isinstance(value, util.collections_abc.Sequence)
+            tokens = [util.text_type(elem) for elem in value]
+            value = "{%s}" % (", ".join(tokens))
+            if super_proc:
+                value = super_proc(value)
+            return value
+
+        return process
+
+
+class JSON(sqltypes.JSON):
+    """Represent the PostgreSQL JSON type.
+
+    :class:`_postgresql.JSON` is used automatically whenever the base
+    :class:`_types.JSON` datatype is used against a PostgreSQL backend,
+    however base :class:`_types.JSON` datatype does not provide Python
+    accessors for PostgreSQL-specific comparison methods such as
+    :meth:`_postgresql.JSON.Comparator.astext`; additionally, to use
+    PostgreSQL ``JSONB``, the :class:`_postgresql.JSONB` datatype should
+    be used explicitly.
+
+    .. seealso::
+
+        :class:`_types.JSON` - main documentation for the generic
+        cross-platform JSON datatype.
+
+    The operators provided by the PostgreSQL version of :class:`_types.JSON`
+    include:
+
+    * Index operations (the ``->`` operator)::
+
+        data_table.c.data['some key']
+
+        data_table.c.data[5]
+
+
+    * Index operations returning text (the ``->>`` operator)::
+
+        data_table.c.data['some key'].astext == 'some value'
+
+      Note that equivalent functionality is available via the
+      :attr:`.JSON.Comparator.as_string` accessor.
+
+    * Index operations with CAST
+      (equivalent to ``CAST(col ->> ['some key'] AS <type>)``)::
+
+        data_table.c.data['some key'].astext.cast(Integer) == 5
+
+      Note that equivalent functionality is available via the
+      :attr:`.JSON.Comparator.as_integer` and similar accessors.
+
+    * Path index operations (the ``#>`` operator)::
+
+        data_table.c.data[('key_1', 'key_2', 5, ..., 'key_n')]
+
+    * Path index operations returning text (the ``#>>`` operator)::
+
+        data_table.c.data[('key_1', 'key_2', 5, ..., 'key_n')].astext == 'some value'
+
+    .. versionchanged:: 1.1  The :meth:`_expression.ColumnElement.cast`
+       operator on
+       JSON objects now requires that the :attr:`.JSON.Comparator.astext`
+       modifier be called explicitly, if the cast works only from a textual
+       string.
+
+    Index operations return an expression object whose type defaults to
+    :class:`_types.JSON` by default,
+    so that further JSON-oriented instructions
+    may be called upon the result type.
+
+    Custom serializers and deserializers are specified at the dialect level,
+    that is using :func:`_sa.create_engine`.  The reason for this is that when
+    using psycopg2, the DBAPI only allows serializers at the per-cursor
+    or per-connection level.   E.g.::
+
+        engine = create_engine("postgresql://scott:tiger@localhost/test",
+                                json_serializer=my_serialize_fn,
+                                json_deserializer=my_deserialize_fn
+                        )
+
+    When using the psycopg2 dialect, the json_deserializer is registered
+    against the database using ``psycopg2.extras.register_default_json``.
+
+    .. seealso::
+
+        :class:`_types.JSON` - Core level JSON type
+
+        :class:`_postgresql.JSONB`
+
+    .. versionchanged:: 1.1 :class:`_postgresql.JSON` is now a PostgreSQL-
+       specific specialization of the new :class:`_types.JSON` type.
+
+    """  # noqa
+
+    astext_type = sqltypes.Text()
+
+    def __init__(self, none_as_null=False, astext_type=None):
+        """Construct a :class:`_types.JSON` type.
+
+        :param none_as_null: if True, persist the value ``None`` as a
+         SQL NULL value, not the JSON encoding of ``null``.   Note that
+         when this flag is False, the :func:`.null` construct can still
+         be used to persist a NULL value::
+
+             from sqlalchemy import null
+             conn.execute(table.insert(), data=null())
+
+         .. versionchanged:: 0.9.8 - Added ``none_as_null``, and :func:`.null`
+            is now supported in order to persist a NULL value.
+
+         .. seealso::
+
+              :attr:`_types.JSON.NULL`
+
+        :param astext_type: the type to use for the
+         :attr:`.JSON.Comparator.astext`
+         accessor on indexed attributes.  Defaults to :class:`_types.Text`.
+
+         .. versionadded:: 1.1
+
+        """
+        super(JSON, self).__init__(none_as_null=none_as_null)
+        if astext_type is not None:
+            self.astext_type = astext_type
+
+    class Comparator(sqltypes.JSON.Comparator):
+        """Define comparison operations for :class:`_types.JSON`."""
+
+        @property
+        def astext(self):
+            """On an indexed expression, use the "astext" (e.g. "->>")
+            conversion when rendered in SQL.
+
+            E.g.::
+
+                select(data_table.c.data['some key'].astext)
+
+            .. seealso::
+
+                :meth:`_expression.ColumnElement.cast`
+
+            """
+            if isinstance(self.expr.right.type, sqltypes.JSON.JSONPathType):
+                return self.expr.left.operate(
+                    JSONPATH_ASTEXT,
+                    self.expr.right,
+                    result_type=self.type.astext_type,
+                )
+            else:
+                return self.expr.left.operate(
+                    ASTEXT, self.expr.right, result_type=self.type.astext_type
+                )
+
+    comparator_factory = Comparator
+
+
+class JSONB(JSON):
+    """Represent the PostgreSQL JSONB type.
+
+    The :class:`_postgresql.JSONB` type stores arbitrary JSONB format data,
+    e.g.::
+
+        data_table = Table('data_table', metadata,
+            Column('id', Integer, primary_key=True),
+            Column('data', JSONB)
+        )
+
+        with engine.connect() as conn:
+            conn.execute(
+                data_table.insert(),
+                data = {"key1": "value1", "key2": "value2"}
+            )
+
+    The :class:`_postgresql.JSONB` type includes all operations provided by
+    :class:`_types.JSON`, including the same behaviors for indexing
+    operations.
+    It also adds additional operators specific to JSONB, including
+    :meth:`.JSONB.Comparator.has_key`, :meth:`.JSONB.Comparator.has_all`,
+    :meth:`.JSONB.Comparator.has_any`, :meth:`.JSONB.Comparator.contains`,
+    and :meth:`.JSONB.Comparator.contained_by`.
+
+    Like the :class:`_types.JSON` type, the :class:`_postgresql.JSONB`
+    type does not detect
+    in-place changes when used with the ORM, unless the
+    :mod:`sqlalchemy.ext.mutable` extension is used.
+
+    Custom serializers and deserializers
+    are shared with the :class:`_types.JSON` class,
+    using the ``json_serializer``
+    and ``json_deserializer`` keyword arguments.  These must be specified
+    at the dialect level using :func:`_sa.create_engine`.  When using
+    psycopg2, the serializers are associated with the jsonb type using
+    ``psycopg2.extras.register_default_jsonb`` on a per-connection basis,
+    in the same way that ``psycopg2.extras.register_default_json`` is used
+    to register these handlers with the json type.
+
+    .. versionadded:: 0.9.7
+
+    .. seealso::
+
+        :class:`_types.JSON`
+
+    """
+
+    __visit_name__ = "JSONB"
+
+    class Comparator(JSON.Comparator):
+        """Define comparison operations for :class:`_types.JSON`."""
+
+        def has_key(self, other):
+            """Boolean expression.  Test for presence of a key.  Note that the
+            key may be a SQLA expression.
+            """
+            return self.operate(HAS_KEY, other, result_type=sqltypes.Boolean)
+
+        def has_all(self, other):
+            """Boolean expression.  Test for presence of all keys in jsonb"""
+            return self.operate(HAS_ALL, other, result_type=sqltypes.Boolean)
+
+        def has_any(self, other):
+            """Boolean expression.  Test for presence of any key in jsonb"""
+            return self.operate(HAS_ANY, other, result_type=sqltypes.Boolean)
+
+        def contains(self, other, **kwargs):
+            """Boolean expression.  Test if keys (or array) are a superset
+            of/contained the keys of the argument jsonb expression.
+
+            kwargs may be ignored by this operator but are required for API
+            conformance.
+            """
+            return self.operate(CONTAINS, other, result_type=sqltypes.Boolean)
+
+        def contained_by(self, other):
+            """Boolean expression.  Test if keys are a proper subset of the
+            keys of the argument jsonb expression.
+            """
+            return self.operate(
+                CONTAINED_BY, other, result_type=sqltypes.Boolean
+            )
+
+    comparator_factory = Comparator

lib/sqlalchemy/dialects/postgresql/pg8000.py

@@ -0,0 +1,594 @@
+# postgresql/pg8000.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors <see AUTHORS
+# file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+r"""
+.. dialect:: postgresql+pg8000
+    :name: pg8000
+    :dbapi: pg8000
+    :connectstring: postgresql+pg8000://user:password@host:port/dbname[?key=value&key=value...]
+    :url: https://pypi.org/project/pg8000/
+
+.. versionchanged:: 1.4  The pg8000 dialect has been updated for version
+   1.16.6 and higher, and is again part of SQLAlchemy's continuous integration
+   with full feature support.
+
+.. _pg8000_unicode:
+
+Unicode
+-------
+
+pg8000 will encode / decode string values between it and the server using the
+PostgreSQL ``client_encoding`` parameter; by default this is the value in
+the ``postgresql.conf`` file, which often defaults to ``SQL_ASCII``.
+Typically, this can be changed to ``utf-8``, as a more useful default::
+
+    #client_encoding = sql_ascii # actually, defaults to database
+                                 # encoding
+    client_encoding = utf8
+
+The ``client_encoding`` can be overridden for a session by executing the SQL:
+
+SET CLIENT_ENCODING TO 'utf8';
+
+SQLAlchemy will execute this SQL on all new connections based on the value
+passed to :func:`_sa.create_engine` using the ``client_encoding`` parameter::
+
+    engine = create_engine(
+        "postgresql+pg8000://user:pass@host/dbname", client_encoding='utf8')
+
+.. _pg8000_ssl:
+
+SSL Connections
+---------------
+
+pg8000 accepts a Python ``SSLContext`` object which may be specified using the
+:paramref:`_sa.create_engine.connect_args` dictionary::
+
+    import ssl
+    ssl_context = ssl.create_default_context()
+    engine = sa.create_engine(
+        "postgresql+pg8000://scott:tiger@192.168.0.199/test",
+        connect_args={"ssl_context": ssl_context},
+    )
+
+If the server uses an automatically-generated certificate that is self-signed
+or does not match the host name (as seen from the client), it may also be
+necessary to disable hostname checking::
+
+    import ssl
+    ssl_context = ssl.create_default_context()
+    ssl_context.check_hostname = False
+    ssl_context.verify_mode = ssl.CERT_NONE
+    engine = sa.create_engine(
+        "postgresql+pg8000://scott:tiger@192.168.0.199/test",
+        connect_args={"ssl_context": ssl_context},
+    )
+
+.. _pg8000_isolation_level:
+
+pg8000 Transaction Isolation Level
+-------------------------------------
+
+The pg8000 dialect offers the same isolation level settings as that
+of the :ref:`psycopg2 <psycopg2_isolation_level>` dialect:
+
+* ``READ COMMITTED``
+* ``READ UNCOMMITTED``
+* ``REPEATABLE READ``
+* ``SERIALIZABLE``
+* ``AUTOCOMMIT``
+
+.. seealso::
+
+    :ref:`postgresql_isolation_level`
+
+    :ref:`psycopg2_isolation_level`
+
+
+"""  # noqa
+import decimal
+import re
+from uuid import UUID as _python_UUID
+
+from .array import ARRAY as PGARRAY
+from .base import _ColonCast
+from .base import _DECIMAL_TYPES
+from .base import _FLOAT_TYPES
+from .base import _INT_TYPES
+from .base import ENUM
+from .base import INTERVAL
+from .base import PGCompiler
+from .base import PGDialect
+from .base import PGExecutionContext
+from .base import PGIdentifierPreparer
+from .base import UUID
+from .json import JSON
+from .json import JSONB
+from .json import JSONPathType
+from ... import exc
+from ... import processors
+from ... import types as sqltypes
+from ... import util
+from ...sql.elements import quoted_name
+
+
+class _PGNumeric(sqltypes.Numeric):
+    def result_processor(self, dialect, coltype):
+        if self.asdecimal:
+            if coltype in _FLOAT_TYPES:
+                return processors.to_decimal_processor_factory(
+                    decimal.Decimal, self._effective_decimal_return_scale
+                )
+            elif coltype in _DECIMAL_TYPES or coltype in _INT_TYPES:
+                # pg8000 returns Decimal natively for 1700
+                return None
+            else:
+                raise exc.InvalidRequestError(
+                    "Unknown PG numeric type: %d" % coltype
+                )
+        else:
+            if coltype in _FLOAT_TYPES:
+                # pg8000 returns float natively for 701
+                return None
+            elif coltype in _DECIMAL_TYPES or coltype in _INT_TYPES:
+                return processors.to_float
+            else:
+                raise exc.InvalidRequestError(
+                    "Unknown PG numeric type: %d" % coltype
+                )
+
+
+class _PGNumericNoBind(_PGNumeric):
+    def bind_processor(self, dialect):
+        return None
+
+
+class _PGJSON(JSON):
+    def result_processor(self, dialect, coltype):
+        return None
+
+    def get_dbapi_type(self, dbapi):
+        return dbapi.JSON
+
+
+class _PGJSONB(JSONB):
+    def result_processor(self, dialect, coltype):
+        return None
+
+    def get_dbapi_type(self, dbapi):
+        return dbapi.JSONB
+
+
+class _PGJSONIndexType(sqltypes.JSON.JSONIndexType):
+    def get_dbapi_type(self, dbapi):
+        raise NotImplementedError("should not be here")
+
+
+class _PGJSONIntIndexType(sqltypes.JSON.JSONIntIndexType):
+    def get_dbapi_type(self, dbapi):
+        return dbapi.INTEGER
+
+
+class _PGJSONStrIndexType(sqltypes.JSON.JSONStrIndexType):
+    def get_dbapi_type(self, dbapi):
+        return dbapi.STRING
+
+
+class _PGJSONPathType(JSONPathType):
+    def get_dbapi_type(self, dbapi):
+        return 1009
+
+
+class _PGUUID(UUID):
+    def bind_processor(self, dialect):
+        if not self.as_uuid:
+
+            def process(value):
+                if value is not None:
+                    value = _python_UUID(value)
+                return value
+
+            return process
+
+    def result_processor(self, dialect, coltype):
+        if not self.as_uuid:
+
+            def process(value):
+                if value is not None:
+                    value = str(value)
+                return value
+
+            return process
+
+
+class _PGEnum(ENUM):
+    def get_dbapi_type(self, dbapi):
+        return dbapi.UNKNOWN
+
+
+class _PGInterval(INTERVAL):
+    def get_dbapi_type(self, dbapi):
+        return dbapi.INTERVAL
+
+    @classmethod
+    def adapt_emulated_to_native(cls, interval, **kw):
+        return _PGInterval(precision=interval.second_precision)
+
+
+class _PGTimeStamp(sqltypes.DateTime):
+    def get_dbapi_type(self, dbapi):
+        if self.timezone:
+            # TIMESTAMPTZOID
+            return 1184
+        else:
+            # TIMESTAMPOID
+            return 1114
+
+
+class _PGTime(sqltypes.Time):
+    def get_dbapi_type(self, dbapi):
+        return dbapi.TIME
+
+
+class _PGInteger(sqltypes.Integer):
+    def get_dbapi_type(self, dbapi):
+        return dbapi.INTEGER
+
+
+class _PGSmallInteger(sqltypes.SmallInteger):
+    def get_dbapi_type(self, dbapi):
+        return dbapi.INTEGER
+
+
+class _PGNullType(sqltypes.NullType):
+    def get_dbapi_type(self, dbapi):
+        return dbapi.NULLTYPE
+
+
+class _PGBigInteger(sqltypes.BigInteger):
+    def get_dbapi_type(self, dbapi):
+        return dbapi.BIGINTEGER
+
+
+class _PGBoolean(sqltypes.Boolean):
+    def get_dbapi_type(self, dbapi):
+        return dbapi.BOOLEAN
+
+
+class _PGARRAY(PGARRAY):
+    def bind_expression(self, bindvalue):
+        return _ColonCast(bindvalue, self)
+
+
+_server_side_id = util.counter()
+
+
+class PGExecutionContext_pg8000(PGExecutionContext):
+    def create_server_side_cursor(self):
+        ident = "c_%s_%s" % (hex(id(self))[2:], hex(_server_side_id())[2:])
+        return ServerSideCursor(self._dbapi_connection.cursor(), ident)
+
+    def pre_exec(self):
+        if not self.compiled:
+            return
+
+
+class ServerSideCursor:
+    server_side = True
+
+    def __init__(self, cursor, ident):
+        self.ident = ident
+        self.cursor = cursor
+
+    @property
+    def connection(self):
+        return self.cursor.connection
+
+    @property
+    def rowcount(self):
+        return self.cursor.rowcount
+
+    @property
+    def description(self):
+        return self.cursor.description
+
+    def execute(self, operation, args=(), stream=None):
+        op = "DECLARE " + self.ident + " NO SCROLL CURSOR FOR " + operation
+        self.cursor.execute(op, args, stream=stream)
+        return self
+
+    def executemany(self, operation, param_sets):
+        self.cursor.executemany(operation, param_sets)
+        return self
+
+    def fetchone(self):
+        self.cursor.execute("FETCH FORWARD 1 FROM " + self.ident)
+        return self.cursor.fetchone()
+
+    def fetchmany(self, num=None):
+        if num is None:
+            return self.fetchall()
+        else:
+            self.cursor.execute(
+                "FETCH FORWARD " + str(int(num)) + " FROM " + self.ident
+            )
+            return self.cursor.fetchall()
+
+    def fetchall(self):
+        self.cursor.execute("FETCH FORWARD ALL FROM " + self.ident)
+        return self.cursor.fetchall()
+
+    def close(self):
+        self.cursor.execute("CLOSE " + self.ident)
+        self.cursor.close()
+
+    def setinputsizes(self, *sizes):
+        self.cursor.setinputsizes(*sizes)
+
+    def setoutputsize(self, size, column=None):
+        pass
+
+
+class PGCompiler_pg8000(PGCompiler):
+    def visit_mod_binary(self, binary, operator, **kw):
+        return (
+            self.process(binary.left, **kw)
+            + " %% "
+            + self.process(binary.right, **kw)
+        )
+
+
+class PGIdentifierPreparer_pg8000(PGIdentifierPreparer):
+    def __init__(self, *args, **kwargs):
+        PGIdentifierPreparer.__init__(self, *args, **kwargs)
+        self._double_percents = False
+
+
+class PGDialect_pg8000(PGDialect):
+    driver = "pg8000"
+    supports_statement_cache = True
+
+    supports_unicode_statements = True
+
+    supports_unicode_binds = True
+
+    default_paramstyle = "format"
+    supports_sane_multi_rowcount = True
+    execution_ctx_cls = PGExecutionContext_pg8000
+    statement_compiler = PGCompiler_pg8000
+    preparer = PGIdentifierPreparer_pg8000
+    supports_server_side_cursors = True
+
+    use_setinputsizes = True
+
+    # reversed as of pg8000 1.16.6.  1.16.5 and lower
+    # are no longer compatible
+    description_encoding = None
+    # description_encoding = "use_encoding"
+
+    colspecs = util.update_copy(
+        PGDialect.colspecs,
+        {
+            sqltypes.Numeric: _PGNumericNoBind,
+            sqltypes.Float: _PGNumeric,
+            sqltypes.JSON: _PGJSON,
+            sqltypes.Boolean: _PGBoolean,
+            sqltypes.NullType: _PGNullType,
+            JSONB: _PGJSONB,
+            sqltypes.JSON.JSONPathType: _PGJSONPathType,
+            sqltypes.JSON.JSONIndexType: _PGJSONIndexType,
+            sqltypes.JSON.JSONIntIndexType: _PGJSONIntIndexType,
+            sqltypes.JSON.JSONStrIndexType: _PGJSONStrIndexType,
+            UUID: _PGUUID,
+            sqltypes.Interval: _PGInterval,
+            INTERVAL: _PGInterval,
+            sqltypes.DateTime: _PGTimeStamp,
+            sqltypes.Time: _PGTime,
+            sqltypes.Integer: _PGInteger,
+            sqltypes.SmallInteger: _PGSmallInteger,
+            sqltypes.BigInteger: _PGBigInteger,
+            sqltypes.Enum: _PGEnum,
+            sqltypes.ARRAY: _PGARRAY,
+        },
+    )
+
+    def __init__(self, client_encoding=None, **kwargs):
+        PGDialect.__init__(self, **kwargs)
+        self.client_encoding = client_encoding
+
+        if self._dbapi_version < (1, 16, 6):
+            raise NotImplementedError("pg8000 1.16.6 or greater is required")
+
+    @util.memoized_property
+    def _dbapi_version(self):
+        if self.dbapi and hasattr(self.dbapi, "__version__"):
+            return tuple(
+                [
+                    int(x)
+                    for x in re.findall(
+                        r"(\d+)(?:[-\.]?|$)", self.dbapi.__version__
+                    )
+                ]
+            )
+        else:
+            return (99, 99, 99)
+
+    @classmethod
+    def dbapi(cls):
+        return __import__("pg8000")
+
+    def create_connect_args(self, url):
+        opts = url.translate_connect_args(username="user")
+        if "port" in opts:
+            opts["port"] = int(opts["port"])
+        opts.update(url.query)
+        return ([], opts)
+
+    def is_disconnect(self, e, connection, cursor):
+        if isinstance(e, self.dbapi.InterfaceError) and "network error" in str(
+            e
+        ):
+            # new as of pg8000 1.19.0 for broken connections
+            return True
+
+        # connection was closed normally
+        return "connection is closed" in str(e)
+
+    def set_isolation_level(self, connection, level):
+        level = level.replace("_", " ")
+
+        # adjust for ConnectionFairy possibly being present
+        if hasattr(connection, "dbapi_connection"):
+            connection = connection.dbapi_connection
+
+        if level == "AUTOCOMMIT":
+            connection.autocommit = True
+        elif level in self._isolation_lookup:
+            connection.autocommit = False
+            cursor = connection.cursor()
+            cursor.execute(
+                "SET SESSION CHARACTERISTICS AS TRANSACTION "
+                "ISOLATION LEVEL %s" % level
+            )
+            cursor.execute("COMMIT")
+            cursor.close()
+        else:
+            raise exc.ArgumentError(
+                "Invalid value '%s' for isolation_level. "
+                "Valid isolation levels for %s are %s or AUTOCOMMIT"
+                % (level, self.name, ", ".join(self._isolation_lookup))
+            )
+
+    def set_readonly(self, connection, value):
+        cursor = connection.cursor()
+        try:
+            cursor.execute(
+                "SET SESSION CHARACTERISTICS AS TRANSACTION %s"
+                % ("READ ONLY" if value else "READ WRITE")
+            )
+            cursor.execute("COMMIT")
+        finally:
+            cursor.close()
+
+    def get_readonly(self, connection):
+        cursor = connection.cursor()
+        try:
+            cursor.execute("show transaction_read_only")
+            val = cursor.fetchone()[0]
+        finally:
+            cursor.close()
+
+        return val == "on"
+
+    def set_deferrable(self, connection, value):
+        cursor = connection.cursor()
+        try:
+            cursor.execute(
+                "SET SESSION CHARACTERISTICS AS TRANSACTION %s"
+                % ("DEFERRABLE" if value else "NOT DEFERRABLE")
+            )
+            cursor.execute("COMMIT")
+        finally:
+            cursor.close()
+
+    def get_deferrable(self, connection):
+        cursor = connection.cursor()
+        try:
+            cursor.execute("show transaction_deferrable")
+            val = cursor.fetchone()[0]
+        finally:
+            cursor.close()
+
+        return val == "on"
+
+    def set_client_encoding(self, connection, client_encoding):
+        # adjust for ConnectionFairy possibly being present
+        if hasattr(connection, "dbapi_connection"):
+            connection = connection.dbapi_connection
+
+        cursor = connection.cursor()
+        cursor.execute("SET CLIENT_ENCODING TO '" + client_encoding + "'")
+        cursor.execute("COMMIT")
+        cursor.close()
+
+    def do_set_input_sizes(self, cursor, list_of_tuples, context):
+        if self.positional:
+            cursor.setinputsizes(
+                *[dbtype for key, dbtype, sqltype in list_of_tuples]
+            )
+        else:
+            cursor.setinputsizes(
+                **{
+                    key: dbtype
+                    for key, dbtype, sqltype in list_of_tuples
+                    if dbtype
+                }
+            )
+
+    def do_begin_twophase(self, connection, xid):
+        connection.connection.tpc_begin((0, xid, ""))
+
+    def do_prepare_twophase(self, connection, xid):
+        connection.connection.tpc_prepare()
+
+    def do_rollback_twophase(
+        self, connection, xid, is_prepared=True, recover=False
+    ):
+        connection.connection.tpc_rollback((0, xid, ""))
+
+    def do_commit_twophase(
+        self, connection, xid, is_prepared=True, recover=False
+    ):
+        connection.connection.tpc_commit((0, xid, ""))
+
+    def do_recover_twophase(self, connection):
+        return [row[1] for row in connection.connection.tpc_recover()]
+
+    def on_connect(self):
+        fns = []
+
+        def on_connect(conn):
+            conn.py_types[quoted_name] = conn.py_types[util.text_type]
+
+        fns.append(on_connect)
+
+        if self.client_encoding is not None:
+
+            def on_connect(conn):
+                self.set_client_encoding(conn, self.client_encoding)
+
+            fns.append(on_connect)
+
+        if self.isolation_level is not None:
+
+            def on_connect(conn):
+                self.set_isolation_level(conn, self.isolation_level)
+
+            fns.append(on_connect)
+
+        if self._json_deserializer:
+
+            def on_connect(conn):
+                # json
+                conn.register_in_adapter(114, self._json_deserializer)
+
+                # jsonb
+                conn.register_in_adapter(3802, self._json_deserializer)
+
+            fns.append(on_connect)
+
+        if len(fns) > 0:
+
+            def on_connect(conn):
+                for fn in fns:
+                    fn(conn)
+
+            return on_connect
+        else:
+            return None
+
+
+dialect = PGDialect_pg8000

lib/sqlalchemy/dialects/postgresql/provision.py

@@ -0,0 +1,124 @@
+import time
+
+from ... import exc
+from ... import inspect
+from ... import text
+from ...testing import warn_test_suite
+from ...testing.provision import create_db
+from ...testing.provision import drop_all_schema_objects_post_tables
+from ...testing.provision import drop_all_schema_objects_pre_tables
+from ...testing.provision import drop_db
+from ...testing.provision import log
+from ...testing.provision import prepare_for_drop_tables
+from ...testing.provision import set_default_schema_on_connection
+from ...testing.provision import temp_table_keyword_args
+
+
+@create_db.for_db("postgresql")
+def _pg_create_db(cfg, eng, ident):
+    template_db = cfg.options.postgresql_templatedb
+
+    with eng.execution_options(isolation_level="AUTOCOMMIT").begin() as conn:
+
+        if not template_db:
+            template_db = conn.exec_driver_sql(
+                "select current_database()"
+            ).scalar()
+
+        attempt = 0
+        while True:
+            try:
+                conn.exec_driver_sql(
+                    "CREATE DATABASE %s TEMPLATE %s" % (ident, template_db)
+                )
+            except exc.OperationalError as err:
+                attempt += 1
+                if attempt >= 3:
+                    raise
+                if "accessed by other users" in str(err):
+                    log.info(
+                        "Waiting to create %s, URI %r, "
+                        "template DB %s is in use sleeping for .5",
+                        ident,
+                        eng.url,
+                        template_db,
+                    )
+                    time.sleep(0.5)
+            except:
+                raise
+            else:
+                break
+
+
+@drop_db.for_db("postgresql")
+def _pg_drop_db(cfg, eng, ident):
+    with eng.connect().execution_options(isolation_level="AUTOCOMMIT") as conn:
+        with conn.begin():
+            conn.execute(
+                text(
+                    "select pg_terminate_backend(pid) from pg_stat_activity "
+                    "where usename=current_user and pid != pg_backend_pid() "
+                    "and datname=:dname"
+                ),
+                dict(dname=ident),
+            )
+            conn.exec_driver_sql("DROP DATABASE %s" % ident)
+
+
+@temp_table_keyword_args.for_db("postgresql")
+def _postgresql_temp_table_keyword_args(cfg, eng):
+    return {"prefixes": ["TEMPORARY"]}
+
+
+@set_default_schema_on_connection.for_db("postgresql")
+def _postgresql_set_default_schema_on_connection(
+    cfg, dbapi_connection, schema_name
+):
+    existing_autocommit = dbapi_connection.autocommit
+    dbapi_connection.autocommit = True
+    cursor = dbapi_connection.cursor()
+    cursor.execute("SET SESSION search_path='%s'" % schema_name)
+    cursor.close()
+    dbapi_connection.autocommit = existing_autocommit
+
+
+@drop_all_schema_objects_pre_tables.for_db("postgresql")
+def drop_all_schema_objects_pre_tables(cfg, eng):
+    with eng.connect().execution_options(isolation_level="AUTOCOMMIT") as conn:
+        for xid in conn.execute("select gid from pg_prepared_xacts").scalars():
+            conn.execute("ROLLBACK PREPARED '%s'" % xid)
+
+
+@drop_all_schema_objects_post_tables.for_db("postgresql")
+def drop_all_schema_objects_post_tables(cfg, eng):
+    from sqlalchemy.dialects import postgresql
+
+    inspector = inspect(eng)
+    with eng.begin() as conn:
+        for enum in inspector.get_enums("*"):
+            conn.execute(
+                postgresql.DropEnumType(
+                    postgresql.ENUM(name=enum["name"], schema=enum["schema"])
+                )
+            )
+
+
+@prepare_for_drop_tables.for_db("postgresql")
+def prepare_for_drop_tables(config, connection):
+    """Ensure there are no locks on the current username/database."""
+
+    result = connection.exec_driver_sql(
+        "select pid, state, wait_event_type, query "
+        # "select pg_terminate_backend(pid), state, wait_event_type "
+        "from pg_stat_activity where "
+        "usename=current_user "
+        "and datname=current_database() and state='idle in transaction' "
+        "and pid != pg_backend_pid()"
+    )
+    rows = result.all()  # noqa
+    if rows:
+        warn_test_suite(
+            "PostgreSQL may not be able to DROP tables due to "
+            "idle in transaction: %s"
+            % ("; ".join(row._mapping["query"] for row in rows))
+        )

lib/sqlalchemy/dialects/postgresql/psycopg2cffi.py

@@ -0,0 +1,60 @@
+# testing/engines.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+r"""
+.. dialect:: postgresql+psycopg2cffi
+    :name: psycopg2cffi
+    :dbapi: psycopg2cffi
+    :connectstring: postgresql+psycopg2cffi://user:password@host:port/dbname[?key=value&key=value...]
+    :url: https://pypi.org/project/psycopg2cffi/
+
+``psycopg2cffi`` is an adaptation of ``psycopg2``, using CFFI for the C
+layer. This makes it suitable for use in e.g. PyPy. Documentation
+is as per ``psycopg2``.
+
+.. versionadded:: 1.0.0
+
+.. seealso::
+
+    :mod:`sqlalchemy.dialects.postgresql.psycopg2`
+
+"""  # noqa
+from .psycopg2 import PGDialect_psycopg2
+
+
+class PGDialect_psycopg2cffi(PGDialect_psycopg2):
+    driver = "psycopg2cffi"
+    supports_unicode_statements = True
+    supports_statement_cache = True
+
+    # psycopg2cffi's first release is 2.5.0, but reports
+    # __version__ as 2.4.4.  Subsequent releases seem to have
+    # fixed this.
+
+    FEATURE_VERSION_MAP = dict(
+        native_json=(2, 4, 4),
+        native_jsonb=(2, 7, 1),
+        sane_multi_rowcount=(2, 4, 4),
+        array_oid=(2, 4, 4),
+        hstore_adapter=(2, 4, 4),
+    )
+
+    @classmethod
+    def dbapi(cls):
+        return __import__("psycopg2cffi")
+
+    @classmethod
+    def _psycopg2_extensions(cls):
+        root = __import__("psycopg2cffi", fromlist=["extensions"])
+        return root.extensions
+
+    @classmethod
+    def _psycopg2_extras(cls):
+        root = __import__("psycopg2cffi", fromlist=["extras"])
+        return root.extras
+
+
+dialect = PGDialect_psycopg2cffi

lib/sqlalchemy/dialects/postgresql/pygresql.py

@@ -0,0 +1,278 @@
+# postgresql/pygresql.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+"""
+.. dialect:: postgresql+pygresql
+    :name: pygresql
+    :dbapi: pgdb
+    :connectstring: postgresql+pygresql://user:password@host:port/dbname[?key=value&key=value...]
+    :url: https://www.pygresql.org/
+
+.. note::
+
+    The pygresql dialect is **not tested as part of SQLAlchemy's continuous
+    integration** and may have unresolved issues.  The recommended PostgreSQL
+    dialect is psycopg2.
+
+.. deprecated:: 1.4 The pygresql DBAPI is deprecated and will be removed
+   in a future version. Please use one of the supported DBAPIs to
+   connect to PostgreSQL.
+
+"""  # noqa
+
+import decimal
+import re
+
+from .base import _DECIMAL_TYPES
+from .base import _FLOAT_TYPES
+from .base import _INT_TYPES
+from .base import PGCompiler
+from .base import PGDialect
+from .base import PGIdentifierPreparer
+from .base import UUID
+from .hstore import HSTORE
+from .json import JSON
+from .json import JSONB
+from ... import exc
+from ... import processors
+from ... import util
+from ...sql.elements import Null
+from ...types import JSON as Json
+from ...types import Numeric
+
+
+class _PGNumeric(Numeric):
+    def bind_processor(self, dialect):
+        return None
+
+    def result_processor(self, dialect, coltype):
+        if not isinstance(coltype, int):
+            coltype = coltype.oid
+        if self.asdecimal:
+            if coltype in _FLOAT_TYPES:
+                return processors.to_decimal_processor_factory(
+                    decimal.Decimal, self._effective_decimal_return_scale
+                )
+            elif coltype in _DECIMAL_TYPES or coltype in _INT_TYPES:
+                # PyGreSQL returns Decimal natively for 1700 (numeric)
+                return None
+            else:
+                raise exc.InvalidRequestError(
+                    "Unknown PG numeric type: %d" % coltype
+                )
+        else:
+            if coltype in _FLOAT_TYPES:
+                # PyGreSQL returns float natively for 701 (float8)
+                return None
+            elif coltype in _DECIMAL_TYPES or coltype in _INT_TYPES:
+                return processors.to_float
+            else:
+                raise exc.InvalidRequestError(
+                    "Unknown PG numeric type: %d" % coltype
+                )
+
+
+class _PGHStore(HSTORE):
+    def bind_processor(self, dialect):
+        if not dialect.has_native_hstore:
+            return super(_PGHStore, self).bind_processor(dialect)
+        hstore = dialect.dbapi.Hstore
+
+        def process(value):
+            if isinstance(value, dict):
+                return hstore(value)
+            return value
+
+        return process
+
+    def result_processor(self, dialect, coltype):
+        if not dialect.has_native_hstore:
+            return super(_PGHStore, self).result_processor(dialect, coltype)
+
+
+class _PGJSON(JSON):
+    def bind_processor(self, dialect):
+        if not dialect.has_native_json:
+            return super(_PGJSON, self).bind_processor(dialect)
+        json = dialect.dbapi.Json
+
+        def process(value):
+            if value is self.NULL:
+                value = None
+            elif isinstance(value, Null) or (
+                value is None and self.none_as_null
+            ):
+                return None
+            if value is None or isinstance(value, (dict, list)):
+                return json(value)
+            return value
+
+        return process
+
+    def result_processor(self, dialect, coltype):
+        if not dialect.has_native_json:
+            return super(_PGJSON, self).result_processor(dialect, coltype)
+
+
+class _PGJSONB(JSONB):
+    def bind_processor(self, dialect):
+        if not dialect.has_native_json:
+            return super(_PGJSONB, self).bind_processor(dialect)
+        json = dialect.dbapi.Json
+
+        def process(value):
+            if value is self.NULL:
+                value = None
+            elif isinstance(value, Null) or (
+                value is None and self.none_as_null
+            ):
+                return None
+            if value is None or isinstance(value, (dict, list)):
+                return json(value)
+            return value
+
+        return process
+
+    def result_processor(self, dialect, coltype):
+        if not dialect.has_native_json:
+            return super(_PGJSONB, self).result_processor(dialect, coltype)
+
+
+class _PGUUID(UUID):
+    def bind_processor(self, dialect):
+        if not dialect.has_native_uuid:
+            return super(_PGUUID, self).bind_processor(dialect)
+        uuid = dialect.dbapi.Uuid
+
+        def process(value):
+            if value is None:
+                return None
+            if isinstance(value, (str, bytes)):
+                if len(value) == 16:
+                    return uuid(bytes=value)
+                return uuid(value)
+            if isinstance(value, int):
+                return uuid(int=value)
+            return value
+
+        return process
+
+    def result_processor(self, dialect, coltype):
+        if not dialect.has_native_uuid:
+            return super(_PGUUID, self).result_processor(dialect, coltype)
+        if not self.as_uuid:
+
+            def process(value):
+                if value is not None:
+                    return str(value)
+
+            return process
+
+
+class _PGCompiler(PGCompiler):
+    def visit_mod_binary(self, binary, operator, **kw):
+        return (
+            self.process(binary.left, **kw)
+            + " %% "
+            + self.process(binary.right, **kw)
+        )
+
+    def post_process_text(self, text):
+        return text.replace("%", "%%")
+
+
+class _PGIdentifierPreparer(PGIdentifierPreparer):
+    def _escape_identifier(self, value):
+        value = value.replace(self.escape_quote, self.escape_to_quote)
+        return value.replace("%", "%%")
+
+
+class PGDialect_pygresql(PGDialect):
+
+    driver = "pygresql"
+    supports_statement_cache = True
+
+    statement_compiler = _PGCompiler
+    preparer = _PGIdentifierPreparer
+
+    @classmethod
+    def dbapi(cls):
+        import pgdb
+
+        util.warn_deprecated(
+            "The pygresql DBAPI is deprecated and will be removed "
+            "in a future version. Please use one of the supported DBAPIs to "
+            "connect to PostgreSQL.",
+            version="1.4",
+        )
+
+        return pgdb
+
+    colspecs = util.update_copy(
+        PGDialect.colspecs,
+        {
+            Numeric: _PGNumeric,
+            HSTORE: _PGHStore,
+            Json: _PGJSON,
+            JSON: _PGJSON,
+            JSONB: _PGJSONB,
+            UUID: _PGUUID,
+        },
+    )
+
+    def __init__(self, **kwargs):
+        super(PGDialect_pygresql, self).__init__(**kwargs)
+        try:
+            version = self.dbapi.version
+            m = re.match(r"(\d+)\.(\d+)", version)
+            version = (int(m.group(1)), int(m.group(2)))
+        except (AttributeError, ValueError, TypeError):
+            version = (0, 0)
+        self.dbapi_version = version
+        if version < (5, 0):
+            has_native_hstore = has_native_json = has_native_uuid = False
+            if version != (0, 0):
+                util.warn(
+                    "PyGreSQL is only fully supported by SQLAlchemy"
+                    " since version 5.0."
+                )
+        else:
+            self.supports_unicode_statements = True
+            self.supports_unicode_binds = True
+            has_native_hstore = has_native_json = has_native_uuid = True
+        self.has_native_hstore = has_native_hstore
+        self.has_native_json = has_native_json
+        self.has_native_uuid = has_native_uuid
+
+    def create_connect_args(self, url):
+        opts = url.translate_connect_args(username="user")
+        if "port" in opts:
+            opts["host"] = "%s:%s" % (
+                opts.get("host", "").rsplit(":", 1)[0],
+                opts.pop("port"),
+            )
+        opts.update(url.query)
+        return [], opts
+
+    def is_disconnect(self, e, connection, cursor):
+        if isinstance(e, self.dbapi.Error):
+            if not connection:
+                return False
+            try:
+                connection = connection.connection
+            except AttributeError:
+                pass
+            else:
+                if not connection:
+                    return False
+            try:
+                return connection.closed
+            except AttributeError:  # PyGreSQL < 5.0
+                return connection._cnx is None
+        return False
+
+
+dialect = PGDialect_pygresql

lib/sqlalchemy/dialects/postgresql/pypostgresql.py

@@ -0,0 +1,126 @@
+# postgresql/pypostgresql.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+"""
+.. dialect:: postgresql+pypostgresql
+    :name: py-postgresql
+    :dbapi: pypostgresql
+    :connectstring: postgresql+pypostgresql://user:password@host:port/dbname[?key=value&key=value...]
+    :url: https://python.projects.pgfoundry.org/
+
+.. note::
+
+    The pypostgresql dialect is **not tested as part of SQLAlchemy's continuous
+    integration** and may have unresolved issues.  The recommended PostgreSQL
+    driver is psycopg2.
+
+.. deprecated:: 1.4 The py-postgresql DBAPI is deprecated and will be removed
+   in a future version. This DBAPI is superseded by the external
+    version available at external-dialect_. Please use the external version or
+    one of the supported DBAPIs to connect to PostgreSQL.
+
+.. TODO update link
+.. _external-dialect: https://github.com/PyGreSQL
+
+"""  # noqa
+
+from .base import PGDialect
+from .base import PGExecutionContext
+from ... import processors
+from ... import types as sqltypes
+from ... import util
+
+
+class PGNumeric(sqltypes.Numeric):
+    def bind_processor(self, dialect):
+        return processors.to_str
+
+    def result_processor(self, dialect, coltype):
+        if self.asdecimal:
+            return None
+        else:
+            return processors.to_float
+
+
+class PGExecutionContext_pypostgresql(PGExecutionContext):
+    pass
+
+
+class PGDialect_pypostgresql(PGDialect):
+    driver = "pypostgresql"
+
+    supports_statement_cache = True
+    supports_unicode_statements = True
+    supports_unicode_binds = True
+    description_encoding = None
+    default_paramstyle = "pyformat"
+
+    # requires trunk version to support sane rowcounts
+    # TODO: use dbapi version information to set this flag appropriately
+    supports_sane_rowcount = True
+    supports_sane_multi_rowcount = False
+
+    execution_ctx_cls = PGExecutionContext_pypostgresql
+    colspecs = util.update_copy(
+        PGDialect.colspecs,
+        {
+            sqltypes.Numeric: PGNumeric,
+            # prevents PGNumeric from being used
+            sqltypes.Float: sqltypes.Float,
+        },
+    )
+
+    @classmethod
+    def dbapi(cls):
+        from postgresql.driver import dbapi20
+
+        # TODO update link
+        util.warn_deprecated(
+            "The py-postgresql DBAPI is deprecated and will be removed "
+            "in a future version. This DBAPI is superseded by the external"
+            "version available at https://github.com/PyGreSQL. Please "
+            "use one of the supported DBAPIs to connect to PostgreSQL.",
+            version="1.4",
+        )
+
+        return dbapi20
+
+    _DBAPI_ERROR_NAMES = [
+        "Error",
+        "InterfaceError",
+        "DatabaseError",
+        "DataError",
+        "OperationalError",
+        "IntegrityError",
+        "InternalError",
+        "ProgrammingError",
+        "NotSupportedError",
+    ]
+
+    @util.memoized_property
+    def dbapi_exception_translation_map(self):
+        if self.dbapi is None:
+            return {}
+
+        return dict(
+            (getattr(self.dbapi, name).__name__, name)
+            for name in self._DBAPI_ERROR_NAMES
+        )
+
+    def create_connect_args(self, url):
+        opts = url.translate_connect_args(username="user")
+        if "port" in opts:
+            opts["port"] = int(opts["port"])
+        else:
+            opts["port"] = 5432
+        opts.update(url.query)
+        return ([], opts)
+
+    def is_disconnect(self, e, connection, cursor):
+        return "connection is closed" in str(e)
+
+
+dialect = PGDialect_pypostgresql

lib/sqlalchemy/dialects/postgresql/ranges.py

@@ -0,0 +1,138 @@
+# Copyright (C) 2013-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from ... import types as sqltypes
+
+
+__all__ = ("INT4RANGE", "INT8RANGE", "NUMRANGE")
+
+
+class RangeOperators(object):
+    """
+    This mixin provides functionality for the Range Operators
+    listed in the Range Operators table of the `PostgreSQL documentation`__
+    for Range Functions and Operators. It is used by all the range types
+    provided in the ``postgres`` dialect and can likely be used for
+    any range types you create yourself.
+
+    __ https://www.postgresql.org/docs/current/static/functions-range.html
+
+    No extra support is provided for the Range Functions listed in the Range
+    Functions table of the PostgreSQL documentation. For these, the normal
+    :func:`~sqlalchemy.sql.expression.func` object should be used.
+
+    """
+
+    class comparator_factory(sqltypes.Concatenable.Comparator):
+        """Define comparison operations for range types."""
+
+        def __ne__(self, other):
+            "Boolean expression. Returns true if two ranges are not equal"
+            if other is None:
+                return super(RangeOperators.comparator_factory, self).__ne__(
+                    other
+                )
+            else:
+                return self.expr.op("<>", is_comparison=True)(other)
+
+        def contains(self, other, **kw):
+            """Boolean expression. Returns true if the right hand operand,
+            which can be an element or a range, is contained within the
+            column.
+
+            kwargs may be ignored by this operator but are required for API
+            conformance.
+            """
+            return self.expr.op("@>", is_comparison=True)(other)
+
+        def contained_by(self, other):
+            """Boolean expression. Returns true if the column is contained
+            within the right hand operand.
+            """
+            return self.expr.op("<@", is_comparison=True)(other)
+
+        def overlaps(self, other):
+            """Boolean expression. Returns true if the column overlaps
+            (has points in common with) the right hand operand.
+            """
+            return self.expr.op("&&", is_comparison=True)(other)
+
+        def strictly_left_of(self, other):
+            """Boolean expression. Returns true if the column is strictly
+            left of the right hand operand.
+            """
+            return self.expr.op("<<", is_comparison=True)(other)
+
+        __lshift__ = strictly_left_of
+
+        def strictly_right_of(self, other):
+            """Boolean expression. Returns true if the column is strictly
+            right of the right hand operand.
+            """
+            return self.expr.op(">>", is_comparison=True)(other)
+
+        __rshift__ = strictly_right_of
+
+        def not_extend_right_of(self, other):
+            """Boolean expression. Returns true if the range in the column
+            does not extend right of the range in the operand.
+            """
+            return self.expr.op("&<", is_comparison=True)(other)
+
+        def not_extend_left_of(self, other):
+            """Boolean expression. Returns true if the range in the column
+            does not extend left of the range in the operand.
+            """
+            return self.expr.op("&>", is_comparison=True)(other)
+
+        def adjacent_to(self, other):
+            """Boolean expression. Returns true if the range in the column
+            is adjacent to the range in the operand.
+            """
+            return self.expr.op("-|-", is_comparison=True)(other)
+
+        def __add__(self, other):
+            """Range expression. Returns the union of the two ranges.
+            Will raise an exception if the resulting range is not
+            contiguous.
+            """
+            return self.expr.op("+")(other)
+
+
+class INT4RANGE(RangeOperators, sqltypes.TypeEngine):
+    """Represent the PostgreSQL INT4RANGE type."""
+
+    __visit_name__ = "INT4RANGE"
+
+
+class INT8RANGE(RangeOperators, sqltypes.TypeEngine):
+    """Represent the PostgreSQL INT8RANGE type."""
+
+    __visit_name__ = "INT8RANGE"
+
+
+class NUMRANGE(RangeOperators, sqltypes.TypeEngine):
+    """Represent the PostgreSQL NUMRANGE type."""
+
+    __visit_name__ = "NUMRANGE"
+
+
+class DATERANGE(RangeOperators, sqltypes.TypeEngine):
+    """Represent the PostgreSQL DATERANGE type."""
+
+    __visit_name__ = "DATERANGE"
+
+
+class TSRANGE(RangeOperators, sqltypes.TypeEngine):
+    """Represent the PostgreSQL TSRANGE type."""
+
+    __visit_name__ = "TSRANGE"
+
+
+class TSTZRANGE(RangeOperators, sqltypes.TypeEngine):
+    """Represent the PostgreSQL TSTZRANGE type."""
+
+    __visit_name__ = "TSTZRANGE"

lib/sqlalchemy/dialects/sqlite/__init__.py

@@ -0,0 +1,58 @@
+# sqlite/__init__.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from . import base  # noqa
+from . import pysqlcipher  # noqa
+from . import pysqlite  # noqa
+from .base import BLOB
+from .base import BOOLEAN
+from .base import CHAR
+from .base import DATE
+from .base import DATETIME
+from .base import DECIMAL
+from .base import FLOAT
+from .base import INTEGER
+from .base import JSON
+from .base import NUMERIC
+from .base import REAL
+from .base import SMALLINT
+from .base import TEXT
+from .base import TIME
+from .base import TIMESTAMP
+from .base import VARCHAR
+from .dml import Insert
+from .dml import insert
+from ...util import compat
+
+if compat.py3k:
+    from . import aiosqlite  # noqa
+
+# default dialect
+base.dialect = dialect = pysqlite.dialect
+
+
+__all__ = (
+    "BLOB",
+    "BOOLEAN",
+    "CHAR",
+    "DATE",
+    "DATETIME",
+    "DECIMAL",
+    "FLOAT",
+    "INTEGER",
+    "JSON",
+    "NUMERIC",
+    "SMALLINT",
+    "TEXT",
+    "TIME",
+    "TIMESTAMP",
+    "VARCHAR",
+    "REAL",
+    "Insert",
+    "insert",
+    "dialect",
+)

lib/sqlalchemy/dialects/sqlite/aiosqlite.py

@@ -0,0 +1,335 @@
+# sqlite/aiosqlite.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+r"""
+
+.. dialect:: sqlite+aiosqlite
+    :name: aiosqlite
+    :dbapi: aiosqlite
+    :connectstring: sqlite+aiosqlite:///file_path
+    :url: https://pypi.org/project/aiosqlite/
+
+The aiosqlite dialect provides support for the SQLAlchemy asyncio interface
+running on top of pysqlite.
+
+aiosqlite is a wrapper around pysqlite that uses a background thread for
+each connection.   It does not actually use non-blocking IO, as SQLite
+databases are not socket-based.  However it does provide a working asyncio
+interface that's useful for testing and prototyping purposes.
+
+Using a special asyncio mediation layer, the aiosqlite dialect is usable
+as the backend for the :ref:`SQLAlchemy asyncio <asyncio_toplevel>`
+extension package.
+
+This dialect should normally be used only with the
+:func:`_asyncio.create_async_engine` engine creation function::
+
+    from sqlalchemy.ext.asyncio import create_async_engine
+    engine = create_async_engine("sqlite+aiosqlite:///filename")
+
+The URL passes through all arguments to the ``pysqlite`` driver, so all
+connection arguments are the same as they are for that of :ref:`pysqlite`.
+
+
+"""  # noqa
+
+from .base import SQLiteExecutionContext
+from .pysqlite import SQLiteDialect_pysqlite
+from ... import pool
+from ... import util
+from ...engine import AdaptedConnection
+from ...util.concurrency import await_fallback
+from ...util.concurrency import await_only
+
+
+class AsyncAdapt_aiosqlite_cursor:
+    __slots__ = (
+        "_adapt_connection",
+        "_connection",
+        "description",
+        "await_",
+        "_rows",
+        "arraysize",
+        "rowcount",
+        "lastrowid",
+    )
+
+    server_side = False
+
+    def __init__(self, adapt_connection):
+        self._adapt_connection = adapt_connection
+        self._connection = adapt_connection._connection
+        self.await_ = adapt_connection.await_
+        self.arraysize = 1
+        self.rowcount = -1
+        self.description = None
+        self._rows = []
+
+    def close(self):
+        self._rows[:] = []
+
+    def execute(self, operation, parameters=None):
+        try:
+            _cursor = self.await_(self._connection.cursor())
+
+            if parameters is None:
+                self.await_(_cursor.execute(operation))
+            else:
+                self.await_(_cursor.execute(operation, parameters))
+
+            if _cursor.description:
+                self.description = _cursor.description
+                self.lastrowid = self.rowcount = -1
+
+                if not self.server_side:
+                    self._rows = self.await_(_cursor.fetchall())
+            else:
+                self.description = None
+                self.lastrowid = _cursor.lastrowid
+                self.rowcount = _cursor.rowcount
+
+            if not self.server_side:
+                self.await_(_cursor.close())
+            else:
+                self._cursor = _cursor
+        except Exception as error:
+            self._adapt_connection._handle_exception(error)
+
+    def executemany(self, operation, seq_of_parameters):
+        try:
+            _cursor = self.await_(self._connection.cursor())
+            self.await_(_cursor.executemany(operation, seq_of_parameters))
+            self.description = None
+            self.lastrowid = _cursor.lastrowid
+            self.rowcount = _cursor.rowcount
+            self.await_(_cursor.close())
+        except Exception as error:
+            self._adapt_connection._handle_exception(error)
+
+    def setinputsizes(self, *inputsizes):
+        pass
+
+    def __iter__(self):
+        while self._rows:
+            yield self._rows.pop(0)
+
+    def fetchone(self):
+        if self._rows:
+            return self._rows.pop(0)
+        else:
+            return None
+
+    def fetchmany(self, size=None):
+        if size is None:
+            size = self.arraysize
+
+        retval = self._rows[0:size]
+        self._rows[:] = self._rows[size:]
+        return retval
+
+    def fetchall(self):
+        retval = self._rows[:]
+        self._rows[:] = []
+        return retval
+
+
+class AsyncAdapt_aiosqlite_ss_cursor(AsyncAdapt_aiosqlite_cursor):
+    __slots__ = "_cursor"
+
+    server_side = True
+
+    def __init__(self, *arg, **kw):
+        super().__init__(*arg, **kw)
+        self._cursor = None
+
+    def close(self):
+        if self._cursor is not None:
+            self.await_(self._cursor.close())
+            self._cursor = None
+
+    def fetchone(self):
+        return self.await_(self._cursor.fetchone())
+
+    def fetchmany(self, size=None):
+        if size is None:
+            size = self.arraysize
+        return self.await_(self._cursor.fetchmany(size=size))
+
+    def fetchall(self):
+        return self.await_(self._cursor.fetchall())
+
+
+class AsyncAdapt_aiosqlite_connection(AdaptedConnection):
+    await_ = staticmethod(await_only)
+    __slots__ = ("dbapi", "_connection")
+
+    def __init__(self, dbapi, connection):
+        self.dbapi = dbapi
+        self._connection = connection
+
+    @property
+    def isolation_level(self):
+        return self._connection.isolation_level
+
+    @isolation_level.setter
+    def isolation_level(self, value):
+        try:
+            self._connection.isolation_level = value
+        except Exception as error:
+            self._handle_exception(error)
+
+    def create_function(self, *args, **kw):
+        try:
+            self.await_(self._connection.create_function(*args, **kw))
+        except Exception as error:
+            self._handle_exception(error)
+
+    def cursor(self, server_side=False):
+        if server_side:
+            return AsyncAdapt_aiosqlite_ss_cursor(self)
+        else:
+            return AsyncAdapt_aiosqlite_cursor(self)
+
+    def execute(self, *args, **kw):
+        return self.await_(self._connection.execute(*args, **kw))
+
+    def rollback(self):
+        try:
+            self.await_(self._connection.rollback())
+        except Exception as error:
+            self._handle_exception(error)
+
+    def commit(self):
+        try:
+            self.await_(self._connection.commit())
+        except Exception as error:
+            self._handle_exception(error)
+
+    def close(self):
+        try:
+            self.await_(self._connection.close())
+        except Exception as error:
+            self._handle_exception(error)
+
+    def _handle_exception(self, error):
+        if (
+            isinstance(error, ValueError)
+            and error.args[0] == "no active connection"
+        ):
+            util.raise_(
+                self.dbapi.sqlite.OperationalError("no active connection"),
+                from_=error,
+            )
+        else:
+            raise error
+
+
+class AsyncAdaptFallback_aiosqlite_connection(AsyncAdapt_aiosqlite_connection):
+    __slots__ = ()
+
+    await_ = staticmethod(await_fallback)
+
+
+class AsyncAdapt_aiosqlite_dbapi:
+    def __init__(self, aiosqlite, sqlite):
+        self.aiosqlite = aiosqlite
+        self.sqlite = sqlite
+        self.paramstyle = "qmark"
+        self._init_dbapi_attributes()
+
+    def _init_dbapi_attributes(self):
+        for name in (
+            "DatabaseError",
+            "Error",
+            "IntegrityError",
+            "NotSupportedError",
+            "OperationalError",
+            "ProgrammingError",
+            "sqlite_version",
+            "sqlite_version_info",
+        ):
+            setattr(self, name, getattr(self.aiosqlite, name))
+
+        for name in ("PARSE_COLNAMES", "PARSE_DECLTYPES"):
+            setattr(self, name, getattr(self.sqlite, name))
+
+        for name in ("Binary",):
+            setattr(self, name, getattr(self.sqlite, name))
+
+    def connect(self, *arg, **kw):
+        async_fallback = kw.pop("async_fallback", False)
+
+        # Q. WHY do we need this?
+        # A. Because there is no way to set connection.isolation_level
+        #    otherwise
+        # Q. BUT HOW do you know it is SAFE ?????
+        # A. The only operation that isn't safe is the isolation level set
+        #    operation which aiosqlite appears to have let slip through even
+        #    though pysqlite appears to do check_same_thread for this.
+        #    All execute operations etc. should be safe because they all
+        #    go through the single executor thread.
+
+        kw["check_same_thread"] = False
+
+        connection = self.aiosqlite.connect(*arg, **kw)
+
+        # it's a Thread.   you'll thank us later
+        connection.daemon = True
+
+        if util.asbool(async_fallback):
+            return AsyncAdaptFallback_aiosqlite_connection(
+                self,
+                await_fallback(connection),
+            )
+        else:
+            return AsyncAdapt_aiosqlite_connection(
+                self,
+                await_only(connection),
+            )
+
+
+class SQLiteExecutionContext_aiosqlite(SQLiteExecutionContext):
+    def create_server_side_cursor(self):
+        return self._dbapi_connection.cursor(server_side=True)
+
+
+class SQLiteDialect_aiosqlite(SQLiteDialect_pysqlite):
+    driver = "aiosqlite"
+    supports_statement_cache = True
+
+    is_async = True
+
+    supports_server_side_cursors = True
+
+    execution_ctx_cls = SQLiteExecutionContext_aiosqlite
+
+    @classmethod
+    def dbapi(cls):
+        return AsyncAdapt_aiosqlite_dbapi(
+            __import__("aiosqlite"), __import__("sqlite3")
+        )
+
+    @classmethod
+    def get_pool_class(cls, url):
+        if cls._is_url_file_db(url):
+            return pool.NullPool
+        else:
+            return pool.StaticPool
+
+    def is_disconnect(self, e, connection, cursor):
+        if isinstance(
+            e, self.dbapi.OperationalError
+        ) and "no active connection" in str(e):
+            return True
+
+        return super().is_disconnect(e, connection, cursor)
+
+    def get_driver_connection(self, connection):
+        return connection._connection
+
+
+dialect = SQLiteDialect_aiosqlite

lib/sqlalchemy/dialects/sqlite/dml.py

@@ -0,0 +1,200 @@
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from ... import util
+from ...sql import coercions
+from ...sql import roles
+from ...sql.base import _exclusive_against
+from ...sql.base import _generative
+from ...sql.base import ColumnCollection
+from ...sql.dml import Insert as StandardInsert
+from ...sql.elements import ClauseElement
+from ...sql.expression import alias
+from ...util.langhelpers import public_factory
+
+
+__all__ = ("Insert", "insert")
+
+
+class Insert(StandardInsert):
+    """SQLite-specific implementation of INSERT.
+
+    Adds methods for SQLite-specific syntaxes such as ON CONFLICT.
+
+    The :class:`_sqlite.Insert` object is created using the
+    :func:`sqlalchemy.dialects.sqlite.insert` function.
+
+    .. versionadded:: 1.4
+
+    .. seealso::
+
+        :ref:`sqlite_on_conflict_insert`
+
+    """
+
+    stringify_dialect = "sqlite"
+    inherit_cache = False
+
+    @util.memoized_property
+    def excluded(self):
+        """Provide the ``excluded`` namespace for an ON CONFLICT statement
+
+        SQLite's ON CONFLICT clause allows reference to the row that would
+        be inserted, known as ``excluded``.  This attribute provides
+        all columns in this row to be referenceable.
+
+        .. tip::  The :attr:`_sqlite.Insert.excluded` attribute is an instance
+            of :class:`_expression.ColumnCollection`, which provides an
+            interface the same as that of the :attr:`_schema.Table.c`
+            collection described at :ref:`metadata_tables_and_columns`.
+            With this collection, ordinary names are accessible like attributes
+            (e.g. ``stmt.excluded.some_column``), but special names and
+            dictionary method names should be accessed using indexed access,
+            such as ``stmt.excluded["column name"]`` or
+            ``stmt.excluded["values"]``.  See the docstring for
+            :class:`_expression.ColumnCollection` for further examples.
+
+        """
+        return alias(self.table, name="excluded").columns
+
+    _on_conflict_exclusive = _exclusive_against(
+        "_post_values_clause",
+        msgs={
+            "_post_values_clause": "This Insert construct already has "
+            "an ON CONFLICT clause established"
+        },
+    )
+
+    @_generative
+    @_on_conflict_exclusive
+    def on_conflict_do_update(
+        self,
+        index_elements=None,
+        index_where=None,
+        set_=None,
+        where=None,
+    ):
+        r"""
+        Specifies a DO UPDATE SET action for ON CONFLICT clause.
+
+        :param index_elements:
+         A sequence consisting of string column names, :class:`_schema.Column`
+         objects, or other column expression objects that will be used
+         to infer a target index or unique constraint.
+
+        :param index_where:
+         Additional WHERE criterion that can be used to infer a
+         conditional target index.
+
+        :param set\_:
+         A dictionary or other mapping object
+         where the keys are either names of columns in the target table,
+         or :class:`_schema.Column` objects or other ORM-mapped columns
+         matching that of the target table, and expressions or literals
+         as values, specifying the ``SET`` actions to take.
+
+         .. versionadded:: 1.4 The
+            :paramref:`_sqlite.Insert.on_conflict_do_update.set_`
+            parameter supports :class:`_schema.Column` objects from the target
+            :class:`_schema.Table` as keys.
+
+         .. warning:: This dictionary does **not** take into account
+            Python-specified default UPDATE values or generation functions,
+            e.g. those specified using :paramref:`_schema.Column.onupdate`.
+            These values will not be exercised for an ON CONFLICT style of
+            UPDATE, unless they are manually specified in the
+            :paramref:`.Insert.on_conflict_do_update.set_` dictionary.
+
+        :param where:
+         Optional argument. If present, can be a literal SQL
+         string or an acceptable expression for a ``WHERE`` clause
+         that restricts the rows affected by ``DO UPDATE SET``. Rows
+         not meeting the ``WHERE`` condition will not be updated
+         (effectively a ``DO NOTHING`` for those rows).
+
+        """
+
+        self._post_values_clause = OnConflictDoUpdate(
+            index_elements, index_where, set_, where
+        )
+
+    @_generative
+    @_on_conflict_exclusive
+    def on_conflict_do_nothing(self, index_elements=None, index_where=None):
+        """
+        Specifies a DO NOTHING action for ON CONFLICT clause.
+
+        :param index_elements:
+         A sequence consisting of string column names, :class:`_schema.Column`
+         objects, or other column expression objects that will be used
+         to infer a target index or unique constraint.
+
+        :param index_where:
+         Additional WHERE criterion that can be used to infer a
+         conditional target index.
+
+        """
+
+        self._post_values_clause = OnConflictDoNothing(
+            index_elements, index_where
+        )
+
+
+insert = public_factory(
+    Insert, ".dialects.sqlite.insert", ".dialects.sqlite.Insert"
+)
+
+
+class OnConflictClause(ClauseElement):
+    stringify_dialect = "sqlite"
+
+    def __init__(self, index_elements=None, index_where=None):
+
+        if index_elements is not None:
+            self.constraint_target = None
+            self.inferred_target_elements = index_elements
+            self.inferred_target_whereclause = index_where
+        else:
+            self.constraint_target = (
+                self.inferred_target_elements
+            ) = self.inferred_target_whereclause = None
+
+
+class OnConflictDoNothing(OnConflictClause):
+    __visit_name__ = "on_conflict_do_nothing"
+
+
+class OnConflictDoUpdate(OnConflictClause):
+    __visit_name__ = "on_conflict_do_update"
+
+    def __init__(
+        self,
+        index_elements=None,
+        index_where=None,
+        set_=None,
+        where=None,
+    ):
+        super(OnConflictDoUpdate, self).__init__(
+            index_elements=index_elements,
+            index_where=index_where,
+        )
+
+        if isinstance(set_, dict):
+            if not set_:
+                raise ValueError("set parameter dictionary must not be empty")
+        elif isinstance(set_, ColumnCollection):
+            set_ = dict(set_)
+        else:
+            raise ValueError(
+                "set parameter must be a non-empty dictionary "
+                "or a ColumnCollection such as the `.c.` collection "
+                "of a Table object"
+            )
+        self.update_values_to_set = [
+            (coercions.expect(roles.DMLColumnRole, key), value)
+            for key, value in set_.items()
+        ]
+        self.update_whereclause = where

lib/sqlalchemy/dialects/sqlite/json.py

@@ -0,0 +1,84 @@
+from ... import types as sqltypes
+
+
+class JSON(sqltypes.JSON):
+    """SQLite JSON type.
+
+    SQLite supports JSON as of version 3.9 through its JSON1_ extension. Note
+    that JSON1_ is a
+    `loadable extension <https://www.sqlite.org/loadext.html>`_ and as such
+    may not be available, or may require run-time loading.
+
+    :class:`_sqlite.JSON` is used automatically whenever the base
+    :class:`_types.JSON` datatype is used against a SQLite backend.
+
+    .. seealso::
+
+        :class:`_types.JSON` - main documentation for the generic
+        cross-platform JSON datatype.
+
+    The :class:`_sqlite.JSON` type supports persistence of JSON values
+    as well as the core index operations provided by :class:`_types.JSON`
+    datatype, by adapting the operations to render the ``JSON_EXTRACT``
+    function wrapped in the ``JSON_QUOTE`` function at the database level.
+    Extracted values are quoted in order to ensure that the results are
+    always JSON string values.
+
+
+    .. versionadded:: 1.3
+
+
+    .. _JSON1: https://www.sqlite.org/json1.html
+
+    """
+
+
+# Note: these objects currently match exactly those of MySQL, however since
+# these are not generalizable to all JSON implementations, remain separately
+# implemented for each dialect.
+class _FormatTypeMixin(object):
+    def _format_value(self, value):
+        raise NotImplementedError()
+
+    def bind_processor(self, dialect):
+        super_proc = self.string_bind_processor(dialect)
+
+        def process(value):
+            value = self._format_value(value)
+            if super_proc:
+                value = super_proc(value)
+            return value
+
+        return process
+
+    def literal_processor(self, dialect):
+        super_proc = self.string_literal_processor(dialect)
+
+        def process(value):
+            value = self._format_value(value)
+            if super_proc:
+                value = super_proc(value)
+            return value
+
+        return process
+
+
+class JSONIndexType(_FormatTypeMixin, sqltypes.JSON.JSONIndexType):
+    def _format_value(self, value):
+        if isinstance(value, int):
+            value = "$[%s]" % value
+        else:
+            value = '$."%s"' % value
+        return value
+
+
+class JSONPathType(_FormatTypeMixin, sqltypes.JSON.JSONPathType):
+    def _format_value(self, value):
+        return "$%s" % (
+            "".join(
+                [
+                    "[%s]" % elem if isinstance(elem, int) else '."%s"' % elem
+                    for elem in value
+                ]
+            )
+        )

lib/sqlalchemy/dialects/sqlite/provision.py

@@ -0,0 +1,142 @@
+import os
+import re
+
+from ... import exc
+from ...engine import url as sa_url
+from ...testing.provision import create_db
+from ...testing.provision import drop_db
+from ...testing.provision import follower_url_from_main
+from ...testing.provision import generate_driver_url
+from ...testing.provision import log
+from ...testing.provision import post_configure_engine
+from ...testing.provision import run_reap_dbs
+from ...testing.provision import stop_test_class_outside_fixtures
+from ...testing.provision import temp_table_keyword_args
+
+
+# TODO: I can't get this to build dynamically with pytest-xdist procs
+_drivernames = {"pysqlite", "aiosqlite", "pysqlcipher"}
+
+
+@generate_driver_url.for_db("sqlite")
+def generate_driver_url(url, driver, query_str):
+    if driver == "pysqlcipher" and url.get_driver_name() != "pysqlcipher":
+        if url.database:
+            url = url.set(database=url.database + ".enc")
+        url = url.set(password="test")
+    url = url.set(drivername="sqlite+%s" % (driver,))
+    try:
+        url.get_dialect()
+    except exc.NoSuchModuleError:
+        return None
+    else:
+        return url
+
+
+@follower_url_from_main.for_db("sqlite")
+def _sqlite_follower_url_from_main(url, ident):
+    url = sa_url.make_url(url)
+
+    if not url.database or url.database == ":memory:":
+        return url
+    else:
+
+        m = re.match(r"(.+?)\.(.+)$", url.database)
+        name, ext = m.group(1, 2)
+        drivername = url.get_driver_name()
+        return sa_url.make_url(
+            "sqlite+%s:///%s_%s.%s" % (drivername, drivername, ident, ext)
+        )
+
+
+@post_configure_engine.for_db("sqlite")
+def _sqlite_post_configure_engine(url, engine, follower_ident):
+    from sqlalchemy import event
+
+    @event.listens_for(engine, "connect")
+    def connect(dbapi_connection, connection_record):
+        # use file DBs in all cases, memory acts kind of strangely
+        # as an attached
+        if not follower_ident:
+            # note this test_schema.db gets created for all test runs.
+            # there's not any dedicated cleanup step for it.  it in some
+            # ways corresponds to the "test.test_schema" schema that's
+            # expected to be already present, so for now it just stays
+            # in a given checkout directory.
+            dbapi_connection.execute(
+                'ATTACH DATABASE "%s_test_schema.db" AS test_schema'
+                % (engine.driver,)
+            )
+        else:
+            dbapi_connection.execute(
+                'ATTACH DATABASE "%s_%s_test_schema.db" AS test_schema'
+                % (follower_ident, engine.driver)
+            )
+
+
+@create_db.for_db("sqlite")
+def _sqlite_create_db(cfg, eng, ident):
+    pass
+
+
+@drop_db.for_db("sqlite")
+def _sqlite_drop_db(cfg, eng, ident):
+    for path in [
+        "%s.db" % ident,
+        "%s_%s_test_schema.db" % (ident, eng.driver),
+    ]:
+        if os.path.exists(path):
+            log.info("deleting SQLite database file: %s" % path)
+            os.remove(path)
+
+
+@stop_test_class_outside_fixtures.for_db("sqlite")
+def stop_test_class_outside_fixtures(config, db, cls):
+    with db.connect() as conn:
+        files = [
+            row.file
+            for row in conn.exec_driver_sql("PRAGMA database_list")
+            if row.file
+        ]
+
+    if files:
+        db.dispose()
+        # some sqlite file tests are not cleaning up well yet, so do this
+        # just to make things simple for now
+        for file_ in files:
+            if file_ and os.path.exists(file_):
+                os.remove(file_)
+
+
+@temp_table_keyword_args.for_db("sqlite")
+def _sqlite_temp_table_keyword_args(cfg, eng):
+    return {"prefixes": ["TEMPORARY"]}
+
+
+@run_reap_dbs.for_db("sqlite")
+def _reap_sqlite_dbs(url, idents):
+    log.info("db reaper connecting to %r", url)
+
+    log.info("identifiers in file: %s", ", ".join(idents))
+    for ident in idents:
+        # we don't have a config so we can't call _sqlite_drop_db due to the
+        # decorator
+        for ext in ("db", "db.enc"):
+            for path in (
+                ["%s.%s" % (ident, ext)]
+                + [
+                    "%s_%s.%s" % (drivername, ident, ext)
+                    for drivername in _drivernames
+                ]
+                + [
+                    "%s_test_schema.%s" % (drivername, ext)
+                    for drivername in _drivernames
+                ]
+                + [
+                    "%s_%s_test_schema.%s" % (ident, drivername, ext)
+                    for drivername in _drivernames
+                ]
+            ):
+                if os.path.exists(path):
+                    log.info("deleting SQLite database file: %s" % path)
+                    os.remove(path)

lib/sqlalchemy/dialects/sqlite/pysqlcipher.py

@@ -0,0 +1,164 @@
+# sqlite/pysqlcipher.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""
+.. dialect:: sqlite+pysqlcipher
+    :name: pysqlcipher
+    :dbapi: sqlcipher 3 or pysqlcipher
+    :connectstring: sqlite+pysqlcipher://:passphrase@/file_path[?kdf_iter=<iter>]
+
+    Dialect for support of DBAPIs that make use of the
+    `SQLCipher <https://www.zetetic.net/sqlcipher>`_ backend.
+
+
+Driver
+------
+
+Current dialect selection logic is:
+
+* If the :paramref:`_sa.create_engine.module` parameter supplies a DBAPI module,
+  that module is used.
+* Otherwise for Python 3, choose https://pypi.org/project/sqlcipher3/
+* If not available, fall back to https://pypi.org/project/pysqlcipher3/
+* For Python 2, https://pypi.org/project/pysqlcipher/ is used.
+
+.. warning:: The ``pysqlcipher3`` and ``pysqlcipher`` DBAPI drivers are no
+   longer maintained; the ``sqlcipher3`` driver as of this writing appears
+   to be current.  For future compatibility, any pysqlcipher-compatible DBAPI
+   may be used as follows::
+
+        import sqlcipher_compatible_driver
+
+        from sqlalchemy import create_engine
+
+        e = create_engine(
+            "sqlite+pysqlcipher://:password@/dbname.db",
+            module=sqlcipher_compatible_driver
+        )
+
+These drivers make use of the SQLCipher engine. This system essentially
+introduces new PRAGMA commands to SQLite which allows the setting of a
+passphrase and other encryption parameters, allowing the database file to be
+encrypted.
+
+
+Connect Strings
+---------------
+
+The format of the connect string is in every way the same as that
+of the :mod:`~sqlalchemy.dialects.sqlite.pysqlite` driver, except that the
+"password" field is now accepted, which should contain a passphrase::
+
+    e = create_engine('sqlite+pysqlcipher://:testing@/foo.db')
+
+For an absolute file path, two leading slashes should be used for the
+database name::
+
+    e = create_engine('sqlite+pysqlcipher://:testing@//path/to/foo.db')
+
+A selection of additional encryption-related pragmas supported by SQLCipher
+as documented at https://www.zetetic.net/sqlcipher/sqlcipher-api/ can be passed
+in the query string, and will result in that PRAGMA being called for each
+new connection.  Currently, ``cipher``, ``kdf_iter``
+``cipher_page_size`` and ``cipher_use_hmac`` are supported::
+
+    e = create_engine('sqlite+pysqlcipher://:testing@/foo.db?cipher=aes-256-cfb&kdf_iter=64000')
+
+.. warning:: Previous versions of sqlalchemy did not take into consideration
+   the encryption-related pragmas passed in the url string, that were silently
+   ignored. This may cause errors when opening files saved by a
+   previous sqlalchemy version if the encryption options do not match.
+
+
+Pooling Behavior
+----------------
+
+The driver makes a change to the default pool behavior of pysqlite
+as described in :ref:`pysqlite_threading_pooling`.   The pysqlcipher driver
+has been observed to be significantly slower on connection than the
+pysqlite driver, most likely due to the encryption overhead, so the
+dialect here defaults to using the :class:`.SingletonThreadPool`
+implementation,
+instead of the :class:`.NullPool` pool used by pysqlite.  As always, the pool
+implementation is entirely configurable using the
+:paramref:`_sa.create_engine.poolclass` parameter; the :class:`.
+StaticPool` may
+be more feasible for single-threaded use, or :class:`.NullPool` may be used
+to prevent unencrypted connections from being held open for long periods of
+time, at the expense of slower startup time for new connections.
+
+
+"""  # noqa
+
+from __future__ import absolute_import
+
+from .pysqlite import SQLiteDialect_pysqlite
+from ... import pool
+from ... import util
+
+
+class SQLiteDialect_pysqlcipher(SQLiteDialect_pysqlite):
+    driver = "pysqlcipher"
+    supports_statement_cache = True
+
+    pragmas = ("kdf_iter", "cipher", "cipher_page_size", "cipher_use_hmac")
+
+    @classmethod
+    def dbapi(cls):
+        if util.py3k:
+            try:
+                import sqlcipher3 as sqlcipher
+            except ImportError:
+                pass
+            else:
+                return sqlcipher
+
+            from pysqlcipher3 import dbapi2 as sqlcipher
+
+        else:
+            from pysqlcipher import dbapi2 as sqlcipher
+
+        return sqlcipher
+
+    @classmethod
+    def get_pool_class(cls, url):
+        return pool.SingletonThreadPool
+
+    def on_connect_url(self, url):
+        super_on_connect = super(
+            SQLiteDialect_pysqlcipher, self
+        ).on_connect_url(url)
+
+        # pull the info we need from the URL early.  Even though URL
+        # is immutable, we don't want any in-place changes to the URL
+        # to affect things
+        passphrase = url.password or ""
+        url_query = dict(url.query)
+
+        def on_connect(conn):
+            cursor = conn.cursor()
+            cursor.execute('pragma key="%s"' % passphrase)
+            for prag in self.pragmas:
+                value = url_query.get(prag, None)
+                if value is not None:
+                    cursor.execute('pragma %s="%s"' % (prag, value))
+            cursor.close()
+
+            if super_on_connect:
+                super_on_connect(conn)
+
+        return on_connect
+
+    def create_connect_args(self, url):
+        plain_url = url._replace(password=None)
+        plain_url = plain_url.difference_update_query(self.pragmas)
+        return super(SQLiteDialect_pysqlcipher, self).create_connect_args(
+            plain_url
+        )
+
+
+dialect = SQLiteDialect_pysqlcipher

lib/sqlalchemy/dialects/sqlite/pysqlite.py

@@ -0,0 +1,613 @@
+# sqlite/pysqlite.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+r"""
+.. dialect:: sqlite+pysqlite
+    :name: pysqlite
+    :dbapi: sqlite3
+    :connectstring: sqlite+pysqlite:///file_path
+    :url: https://docs.python.org/library/sqlite3.html
+
+    Note that ``pysqlite`` is the same driver as the ``sqlite3``
+    module included with the Python distribution.
+
+Driver
+------
+
+The ``sqlite3`` Python DBAPI is standard on all modern Python versions;
+for cPython and Pypy, no additional installation is necessary.
+
+
+Connect Strings
+---------------
+
+The file specification for the SQLite database is taken as the "database"
+portion of the URL.  Note that the format of a SQLAlchemy url is::
+
+    driver://user:pass@host/database
+
+This means that the actual filename to be used starts with the characters to
+the **right** of the third slash.   So connecting to a relative filepath
+looks like::
+
+    # relative path
+    e = create_engine('sqlite:///path/to/database.db')
+
+An absolute path, which is denoted by starting with a slash, means you
+need **four** slashes::
+
+    # absolute path
+    e = create_engine('sqlite:////path/to/database.db')
+
+To use a Windows path, regular drive specifications and backslashes can be
+used. Double backslashes are probably needed::
+
+    # absolute path on Windows
+    e = create_engine('sqlite:///C:\\path\\to\\database.db')
+
+The sqlite ``:memory:`` identifier is the default if no filepath is
+present.  Specify ``sqlite://`` and nothing else::
+
+    # in-memory database
+    e = create_engine('sqlite://')
+
+.. _pysqlite_uri_connections:
+
+URI Connections
+^^^^^^^^^^^^^^^
+
+Modern versions of SQLite support an alternative system of connecting using a
+`driver level URI <https://www.sqlite.org/uri.html>`_, which has the  advantage
+that additional driver-level arguments can be passed including options such as
+"read only".   The Python sqlite3 driver supports this mode under modern Python
+3 versions.   The SQLAlchemy pysqlite driver supports this mode of use by
+specifying "uri=true" in the URL query string.  The SQLite-level "URI" is kept
+as the "database" portion of the SQLAlchemy url (that is, following a slash)::
+
+    e = create_engine("sqlite:///file:path/to/database?mode=ro&uri=true")
+
+.. note::  The "uri=true" parameter must appear in the **query string**
+   of the URL.  It will not currently work as expected if it is only
+   present in the :paramref:`_sa.create_engine.connect_args`
+   parameter dictionary.
+
+The logic reconciles the simultaneous presence of SQLAlchemy's query string and
+SQLite's query string by separating out the parameters that belong to the
+Python sqlite3 driver vs. those that belong to the SQLite URI.  This is
+achieved through the use of a fixed list of parameters known to be accepted by
+the Python side of the driver.  For example, to include a URL that indicates
+the Python sqlite3 "timeout" and "check_same_thread" parameters, along with the
+SQLite "mode" and "nolock" parameters, they can all be passed together on the
+query string::
+
+    e = create_engine(
+        "sqlite:///file:path/to/database?"
+        "check_same_thread=true&timeout=10&mode=ro&nolock=1&uri=true"
+    )
+
+Above, the pysqlite / sqlite3 DBAPI would be passed arguments as::
+
+    sqlite3.connect(
+        "file:path/to/database?mode=ro&nolock=1",
+        check_same_thread=True, timeout=10, uri=True
+    )
+
+Regarding future parameters added to either the Python or native drivers. new
+parameter names added to the SQLite URI scheme should be automatically
+accommodated by this scheme.  New parameter names added to the Python driver
+side can be accommodated by specifying them in the
+:paramref:`_sa.create_engine.connect_args` dictionary,
+until dialect support is
+added by SQLAlchemy.   For the less likely case that the native SQLite driver
+adds a new parameter name that overlaps with one of the existing, known Python
+driver parameters (such as "timeout" perhaps), SQLAlchemy's dialect would
+require adjustment for the URL scheme to continue to support this.
+
+As is always the case for all SQLAlchemy dialects, the entire "URL" process
+can be bypassed in :func:`_sa.create_engine` through the use of the
+:paramref:`_sa.create_engine.creator`
+parameter which allows for a custom callable
+that creates a Python sqlite3 driver level connection directly.
+
+.. versionadded:: 1.3.9
+
+.. seealso::
+
+    `Uniform Resource Identifiers <https://www.sqlite.org/uri.html>`_ - in
+    the SQLite documentation
+
+.. _pysqlite_regexp:
+
+Regular Expression Support
+---------------------------
+
+.. versionadded:: 1.4
+
+Support for the :meth:`_sql.ColumnOperators.regexp_match` operator is provided
+using Python's re.search_ function.  SQLite itself does not include a working
+regular expression operator; instead, it includes a non-implemented placeholder
+operator ``REGEXP`` that calls a user-defined function that must be provided.
+
+SQLAlchemy's implementation makes use of the pysqlite create_function_ hook
+as follows::
+
+
+    def regexp(a, b):
+        return re.search(a, b) is not None
+
+    sqlite_connection.create_function(
+        "regexp", 2, regexp,
+    )
+
+There is currently no support for regular expression flags as a separate
+argument, as these are not supported by SQLite's REGEXP operator, however these
+may be included inline within the regular expression string.  See `Python regular expressions`_ for
+details.
+
+.. seealso::
+
+    `Python regular expressions`_: Documentation for Python's regular expression syntax.
+
+.. _create_function: https://docs.python.org/3/library/sqlite3.html#sqlite3.Connection.create_function
+
+.. _re.search: https://docs.python.org/3/library/re.html#re.search
+
+.. _Python regular expressions: https://docs.python.org/3/library/re.html#re.search
+
+
+
+Compatibility with sqlite3 "native" date and datetime types
+-----------------------------------------------------------
+
+The pysqlite driver includes the sqlite3.PARSE_DECLTYPES and
+sqlite3.PARSE_COLNAMES options, which have the effect of any column
+or expression explicitly cast as "date" or "timestamp" will be converted
+to a Python date or datetime object.  The date and datetime types provided
+with the pysqlite dialect are not currently compatible with these options,
+since they render the ISO date/datetime including microseconds, which
+pysqlite's driver does not.   Additionally, SQLAlchemy does not at
+this time automatically render the "cast" syntax required for the
+freestanding functions "current_timestamp" and "current_date" to return
+datetime/date types natively.   Unfortunately, pysqlite
+does not provide the standard DBAPI types in ``cursor.description``,
+leaving SQLAlchemy with no way to detect these types on the fly
+without expensive per-row type checks.
+
+Keeping in mind that pysqlite's parsing option is not recommended,
+nor should be necessary, for use with SQLAlchemy, usage of PARSE_DECLTYPES
+can be forced if one configures "native_datetime=True" on create_engine()::
+
+    engine = create_engine('sqlite://',
+        connect_args={'detect_types':
+            sqlite3.PARSE_DECLTYPES|sqlite3.PARSE_COLNAMES},
+        native_datetime=True
+    )
+
+With this flag enabled, the DATE and TIMESTAMP types (but note - not the
+DATETIME or TIME types...confused yet ?) will not perform any bind parameter
+or result processing. Execution of "func.current_date()" will return a string.
+"func.current_timestamp()" is registered as returning a DATETIME type in
+SQLAlchemy, so this function still receives SQLAlchemy-level result
+processing.
+
+.. _pysqlite_threading_pooling:
+
+Threading/Pooling Behavior
+---------------------------
+
+Pysqlite's default behavior is to prohibit the usage of a single connection
+in more than one thread.   This is originally intended to work with older
+versions of SQLite that did not support multithreaded operation under
+various circumstances.  In particular, older SQLite versions
+did not allow a ``:memory:`` database to be used in multiple threads
+under any circumstances.
+
+Pysqlite does include a now-undocumented flag known as
+``check_same_thread`` which will disable this check, however note that
+pysqlite connections are still not safe to use in concurrently in multiple
+threads.  In particular, any statement execution calls would need to be
+externally mutexed, as Pysqlite does not provide for thread-safe propagation
+of error messages among other things.   So while even ``:memory:`` databases
+can be shared among threads in modern SQLite, Pysqlite doesn't provide enough
+thread-safety to make this usage worth it.
+
+SQLAlchemy sets up pooling to work with Pysqlite's default behavior:
+
+* When a ``:memory:`` SQLite database is specified, the dialect by default
+  will use :class:`.SingletonThreadPool`. This pool maintains a single
+  connection per thread, so that all access to the engine within the current
+  thread use the same ``:memory:`` database - other threads would access a
+  different ``:memory:`` database.
+* When a file-based database is specified, the dialect will use
+  :class:`.NullPool` as the source of connections. This pool closes and
+  discards connections which are returned to the pool immediately. SQLite
+  file-based connections have extremely low overhead, so pooling is not
+  necessary. The scheme also prevents a connection from being used again in
+  a different thread and works best with SQLite's coarse-grained file locking.
+
+Using a Memory Database in Multiple Threads
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+To use a ``:memory:`` database in a multithreaded scenario, the same
+connection object must be shared among threads, since the database exists
+only within the scope of that connection.   The
+:class:`.StaticPool` implementation will maintain a single connection
+globally, and the ``check_same_thread`` flag can be passed to Pysqlite
+as ``False``::
+
+    from sqlalchemy.pool import StaticPool
+    engine = create_engine('sqlite://',
+                        connect_args={'check_same_thread':False},
+                        poolclass=StaticPool)
+
+Note that using a ``:memory:`` database in multiple threads requires a recent
+version of SQLite.
+
+Using Temporary Tables with SQLite
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Due to the way SQLite deals with temporary tables, if you wish to use a
+temporary table in a file-based SQLite database across multiple checkouts
+from the connection pool, such as when using an ORM :class:`.Session` where
+the temporary table should continue to remain after :meth:`.Session.commit` or
+:meth:`.Session.rollback` is called, a pool which maintains a single
+connection must be used.   Use :class:`.SingletonThreadPool` if the scope is
+only needed within the current thread, or :class:`.StaticPool` is scope is
+needed within multiple threads for this case::
+
+    # maintain the same connection per thread
+    from sqlalchemy.pool import SingletonThreadPool
+    engine = create_engine('sqlite:///mydb.db',
+                        poolclass=SingletonThreadPool)
+
+
+    # maintain the same connection across all threads
+    from sqlalchemy.pool import StaticPool
+    engine = create_engine('sqlite:///mydb.db',
+                        poolclass=StaticPool)
+
+Note that :class:`.SingletonThreadPool` should be configured for the number
+of threads that are to be used; beyond that number, connections will be
+closed out in a non deterministic way.
+
+Unicode
+-------
+
+The pysqlite driver only returns Python ``unicode`` objects in result sets,
+never plain strings, and accommodates ``unicode`` objects within bound
+parameter values in all cases.   Regardless of the SQLAlchemy string type in
+use, string-based result values will by Python ``unicode`` in Python 2.
+The :class:`.Unicode` type should still be used to indicate those columns that
+require unicode, however, so that non-``unicode`` values passed inadvertently
+will emit a warning.  Pysqlite will emit an error if a non-``unicode`` string
+is passed containing non-ASCII characters.
+
+Dealing with Mixed String / Binary Columns in Python 3
+------------------------------------------------------
+
+The SQLite database is weakly typed, and as such it is possible when using
+binary values, which in Python 3 are represented as ``b'some string'``, that a
+particular SQLite database can have data values within different rows where
+some of them will be returned as a ``b''`` value by the Pysqlite driver, and
+others will be returned as Python strings, e.g. ``''`` values.   This situation
+is not known to occur if the SQLAlchemy :class:`.LargeBinary` datatype is used
+consistently, however if a particular SQLite database has data that was
+inserted using the Pysqlite driver directly, or when using the SQLAlchemy
+:class:`.String` type which was later changed to :class:`.LargeBinary`, the
+table will not be consistently readable because SQLAlchemy's
+:class:`.LargeBinary` datatype does not handle strings so it has no way of
+"encoding" a value that is in string format.
+
+To deal with a SQLite table that has mixed string / binary data in the
+same column, use a custom type that will check each row individually::
+
+    # note this is Python 3 only
+
+    from sqlalchemy import String
+    from sqlalchemy import TypeDecorator
+
+    class MixedBinary(TypeDecorator):
+        impl = String
+        cache_ok = True
+
+        def process_result_value(self, value, dialect):
+            if isinstance(value, str):
+                value = bytes(value, 'utf-8')
+            elif value is not None:
+                value = bytes(value)
+
+            return value
+
+Then use the above ``MixedBinary`` datatype in the place where
+:class:`.LargeBinary` would normally be used.
+
+.. _pysqlite_serializable:
+
+Serializable isolation / Savepoints / Transactional DDL
+-------------------------------------------------------
+
+In the section :ref:`sqlite_concurrency`, we refer to the pysqlite
+driver's assortment of issues that prevent several features of SQLite
+from working correctly.  The pysqlite DBAPI driver has several
+long-standing bugs which impact the correctness of its transactional
+behavior.   In its default mode of operation, SQLite features such as
+SERIALIZABLE isolation, transactional DDL, and SAVEPOINT support are
+non-functional, and in order to use these features, workarounds must
+be taken.
+
+The issue is essentially that the driver attempts to second-guess the user's
+intent, failing to start transactions and sometimes ending them prematurely, in
+an effort to minimize the SQLite databases's file locking behavior, even
+though SQLite itself uses "shared" locks for read-only activities.
+
+SQLAlchemy chooses to not alter this behavior by default, as it is the
+long-expected behavior of the pysqlite driver; if and when the pysqlite
+driver attempts to repair these issues, that will be more of a driver towards
+defaults for SQLAlchemy.
+
+The good news is that with a few events, we can implement transactional
+support fully, by disabling pysqlite's feature entirely and emitting BEGIN
+ourselves. This is achieved using two event listeners::
+
+    from sqlalchemy import create_engine, event
+
+    engine = create_engine("sqlite:///myfile.db")
+
+    @event.listens_for(engine, "connect")
+    def do_connect(dbapi_connection, connection_record):
+        # disable pysqlite's emitting of the BEGIN statement entirely.
+        # also stops it from emitting COMMIT before any DDL.
+        dbapi_connection.isolation_level = None
+
+    @event.listens_for(engine, "begin")
+    def do_begin(conn):
+        # emit our own BEGIN
+        conn.exec_driver_sql("BEGIN")
+
+.. warning:: When using the above recipe, it is advised to not use the
+   :paramref:`.Connection.execution_options.isolation_level` setting on
+   :class:`_engine.Connection` and :func:`_sa.create_engine`
+   with the SQLite driver,
+   as this function necessarily will also alter the ".isolation_level" setting.
+
+
+Above, we intercept a new pysqlite connection and disable any transactional
+integration.   Then, at the point at which SQLAlchemy knows that transaction
+scope is to begin, we emit ``"BEGIN"`` ourselves.
+
+When we take control of ``"BEGIN"``, we can also control directly SQLite's
+locking modes, introduced at
+`BEGIN TRANSACTION <https://sqlite.org/lang_transaction.html>`_,
+by adding the desired locking mode to our ``"BEGIN"``::
+
+    @event.listens_for(engine, "begin")
+    def do_begin(conn):
+        conn.exec_driver_sql("BEGIN EXCLUSIVE")
+
+.. seealso::
+
+    `BEGIN TRANSACTION <https://sqlite.org/lang_transaction.html>`_ -
+    on the SQLite site
+
+    `sqlite3 SELECT does not BEGIN a transaction <https://bugs.python.org/issue9924>`_ -
+    on the Python bug tracker
+
+    `sqlite3 module breaks transactions and potentially corrupts data <https://bugs.python.org/issue10740>`_ -
+    on the Python bug tracker
+
+
+"""  # noqa
+
+import os
+import re
+
+from .base import DATE
+from .base import DATETIME
+from .base import SQLiteDialect
+from ... import exc
+from ... import pool
+from ... import types as sqltypes
+from ... import util
+
+
+class _SQLite_pysqliteTimeStamp(DATETIME):
+    def bind_processor(self, dialect):
+        if dialect.native_datetime:
+            return None
+        else:
+            return DATETIME.bind_processor(self, dialect)
+
+    def result_processor(self, dialect, coltype):
+        if dialect.native_datetime:
+            return None
+        else:
+            return DATETIME.result_processor(self, dialect, coltype)
+
+
+class _SQLite_pysqliteDate(DATE):
+    def bind_processor(self, dialect):
+        if dialect.native_datetime:
+            return None
+        else:
+            return DATE.bind_processor(self, dialect)
+
+    def result_processor(self, dialect, coltype):
+        if dialect.native_datetime:
+            return None
+        else:
+            return DATE.result_processor(self, dialect, coltype)
+
+
+class SQLiteDialect_pysqlite(SQLiteDialect):
+    default_paramstyle = "qmark"
+    supports_statement_cache = True
+
+    colspecs = util.update_copy(
+        SQLiteDialect.colspecs,
+        {
+            sqltypes.Date: _SQLite_pysqliteDate,
+            sqltypes.TIMESTAMP: _SQLite_pysqliteTimeStamp,
+        },
+    )
+
+    if not util.py2k:
+        description_encoding = None
+
+    driver = "pysqlite"
+
+    @classmethod
+    def dbapi(cls):
+        if util.py2k:
+            try:
+                from pysqlite2 import dbapi2 as sqlite
+            except ImportError:
+                try:
+                    from sqlite3 import dbapi2 as sqlite
+                except ImportError as e:
+                    raise e
+        else:
+            from sqlite3 import dbapi2 as sqlite
+        return sqlite
+
+    @classmethod
+    def _is_url_file_db(cls, url):
+        if (url.database and url.database != ":memory:") and (
+            url.query.get("mode", None) != "memory"
+        ):
+            return True
+        else:
+            return False
+
+    @classmethod
+    def get_pool_class(cls, url):
+        if cls._is_url_file_db(url):
+            return pool.NullPool
+        else:
+            return pool.SingletonThreadPool
+
+    def _get_server_version_info(self, connection):
+        return self.dbapi.sqlite_version_info
+
+    _isolation_lookup = SQLiteDialect._isolation_lookup.union(
+        {
+            "AUTOCOMMIT": None,
+        }
+    )
+
+    def set_isolation_level(self, connection, level):
+        if hasattr(connection, "dbapi_connection"):
+            dbapi_connection = connection.dbapi_connection
+        else:
+            dbapi_connection = connection
+
+        if level == "AUTOCOMMIT":
+            dbapi_connection.isolation_level = None
+        else:
+            dbapi_connection.isolation_level = ""
+            return super(SQLiteDialect_pysqlite, self).set_isolation_level(
+                connection, level
+            )
+
+    def on_connect(self):
+        connect = super(SQLiteDialect_pysqlite, self).on_connect()
+
+        def regexp(a, b):
+            if b is None:
+                return None
+            return re.search(a, b) is not None
+
+        def set_regexp(connection):
+            if hasattr(connection, "dbapi_connection"):
+                dbapi_connection = connection.dbapi_connection
+            else:
+                dbapi_connection = connection
+            dbapi_connection.create_function(
+                "regexp",
+                2,
+                regexp,
+            )
+
+        fns = [set_regexp]
+
+        if self.isolation_level is not None:
+
+            def iso_level(conn):
+                self.set_isolation_level(conn, self.isolation_level)
+
+            fns.append(iso_level)
+
+        def connect(conn):
+            for fn in fns:
+                fn(conn)
+
+        return connect
+
+    def create_connect_args(self, url):
+        if url.username or url.password or url.host or url.port:
+            raise exc.ArgumentError(
+                "Invalid SQLite URL: %s\n"
+                "Valid SQLite URL forms are:\n"
+                " sqlite:///:memory: (or, sqlite://)\n"
+                " sqlite:///relative/path/to/file.db\n"
+                " sqlite:////absolute/path/to/file.db" % (url,)
+            )
+
+        # theoretically, this list can be augmented, at least as far as
+        # parameter names accepted by sqlite3/pysqlite, using
+        # inspect.getfullargspec().  for the moment this seems like overkill
+        # as these parameters don't change very often, and as always,
+        # parameters passed to connect_args will always go to the
+        # sqlite3/pysqlite driver.
+        pysqlite_args = [
+            ("uri", bool),
+            ("timeout", float),
+            ("isolation_level", str),
+            ("detect_types", int),
+            ("check_same_thread", bool),
+            ("cached_statements", int),
+        ]
+        opts = url.query
+        pysqlite_opts = {}
+        for key, type_ in pysqlite_args:
+            util.coerce_kw_type(opts, key, type_, dest=pysqlite_opts)
+
+        if pysqlite_opts.get("uri", False):
+            uri_opts = dict(opts)
+            # here, we are actually separating the parameters that go to
+            # sqlite3/pysqlite vs. those that go the SQLite URI.  What if
+            # two names conflict?  again, this seems to be not the case right
+            # now, and in the case that new names are added to
+            # either side which overlap, again the sqlite3/pysqlite parameters
+            # can be passed through connect_args instead of in the URL.
+            # If SQLite native URIs add a parameter like "timeout" that
+            # we already have listed here for the python driver, then we need
+            # to adjust for that here.
+            for key, type_ in pysqlite_args:
+                uri_opts.pop(key, None)
+            filename = url.database
+            if uri_opts:
+                # sorting of keys is for unit test support
+                filename += "?" + (
+                    "&".join(
+                        "%s=%s" % (key, uri_opts[key])
+                        for key in sorted(uri_opts)
+                    )
+                )
+        else:
+            filename = url.database or ":memory:"
+            if filename != ":memory:":
+                filename = os.path.abspath(filename)
+
+        return ([filename], pysqlite_opts)
+
+    def is_disconnect(self, e, connection, cursor):
+        return isinstance(
+            e, self.dbapi.ProgrammingError
+        ) and "Cannot operate on a closed database." in str(e)
+
+
+dialect = SQLiteDialect_pysqlite

lib/sqlalchemy/dialects/sybase/__init__.py

@@ -0,0 +1,67 @@
+# sybase/__init__.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from . import base  # noqa
+from . import pyodbc  # noqa
+from . import pysybase  # noqa
+from .base import BIGINT
+from .base import BINARY
+from .base import BIT
+from .base import CHAR
+from .base import DATE
+from .base import DATETIME
+from .base import FLOAT
+from .base import IMAGE
+from .base import INT
+from .base import INTEGER
+from .base import MONEY
+from .base import NCHAR
+from .base import NUMERIC
+from .base import NVARCHAR
+from .base import SMALLINT
+from .base import SMALLMONEY
+from .base import TEXT
+from .base import TIME
+from .base import TINYINT
+from .base import UNICHAR
+from .base import UNITEXT
+from .base import UNIVARCHAR
+from .base import VARBINARY
+from .base import VARCHAR
+
+
+# default dialect
+base.dialect = dialect = pyodbc.dialect
+
+
+__all__ = (
+    "CHAR",
+    "VARCHAR",
+    "TIME",
+    "NCHAR",
+    "NVARCHAR",
+    "TEXT",
+    "DATE",
+    "DATETIME",
+    "FLOAT",
+    "NUMERIC",
+    "BIGINT",
+    "INT",
+    "INTEGER",
+    "SMALLINT",
+    "BINARY",
+    "VARBINARY",
+    "UNITEXT",
+    "UNICHAR",
+    "UNIVARCHAR",
+    "IMAGE",
+    "BIT",
+    "MONEY",
+    "SMALLMONEY",
+    "TINYINT",
+    "dialect",
+)

lib/sqlalchemy/dialects/sybase/mxodbc.py

@@ -0,0 +1,34 @@
+# sybase/mxodbc.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+"""
+
+.. dialect:: sybase+mxodbc
+    :name: mxODBC
+    :dbapi: mxodbc
+    :connectstring: sybase+mxodbc://<username>:<password>@<dsnname>
+    :url: https://www.egenix.com/
+
+.. note::
+
+    This dialect is a stub only and is likely non functional at this time.
+
+"""
+from sqlalchemy.connectors.mxodbc import MxODBCConnector
+from sqlalchemy.dialects.sybase.base import SybaseDialect
+from sqlalchemy.dialects.sybase.base import SybaseExecutionContext
+
+
+class SybaseExecutionContext_mxodbc(SybaseExecutionContext):
+    pass
+
+
+class SybaseDialect_mxodbc(MxODBCConnector, SybaseDialect):
+    execution_ctx_cls = SybaseExecutionContext_mxodbc
+    supports_statement_cache = True
+
+
+dialect = SybaseDialect_mxodbc

lib/sqlalchemy/dialects/sybase/pyodbc.py

@@ -0,0 +1,89 @@
+# sybase/pyodbc.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""
+.. dialect:: sybase+pyodbc
+    :name: PyODBC
+    :dbapi: pyodbc
+    :connectstring: sybase+pyodbc://<username>:<password>@<dsnname>[/<database>]
+    :url: https://pypi.org/project/pyodbc/
+
+Unicode Support
+---------------
+
+The pyodbc driver currently supports usage of these Sybase types with
+Unicode or multibyte strings::
+
+    CHAR
+    NCHAR
+    NVARCHAR
+    TEXT
+    VARCHAR
+
+Currently *not* supported are::
+
+    UNICHAR
+    UNITEXT
+    UNIVARCHAR
+
+"""  # noqa
+
+import decimal
+
+from sqlalchemy import processors
+from sqlalchemy import types as sqltypes
+from sqlalchemy.connectors.pyodbc import PyODBCConnector
+from sqlalchemy.dialects.sybase.base import SybaseDialect
+from sqlalchemy.dialects.sybase.base import SybaseExecutionContext
+
+
+class _SybNumeric_pyodbc(sqltypes.Numeric):
+    """Turns Decimals with adjusted() < -6 into floats.
+
+    It's not yet known how to get decimals with many
+    significant digits or very large adjusted() into Sybase
+    via pyodbc.
+
+    """
+
+    def bind_processor(self, dialect):
+        super_process = super(_SybNumeric_pyodbc, self).bind_processor(dialect)
+
+        def process(value):
+            if self.asdecimal and isinstance(value, decimal.Decimal):
+
+                if value.adjusted() < -6:
+                    return processors.to_float(value)
+
+            if super_process:
+                return super_process(value)
+            else:
+                return value
+
+        return process
+
+
+class SybaseExecutionContext_pyodbc(SybaseExecutionContext):
+    def set_ddl_autocommit(self, connection, value):
+        if value:
+            connection.autocommit = True
+        else:
+            connection.autocommit = False
+
+
+class SybaseDialect_pyodbc(PyODBCConnector, SybaseDialect):
+    execution_ctx_cls = SybaseExecutionContext_pyodbc
+    supports_statement_cache = True
+
+    colspecs = {sqltypes.Numeric: _SybNumeric_pyodbc}
+
+    @classmethod
+    def dbapi(cls):
+        return PyODBCConnector.dbapi()
+
+
+dialect = SybaseDialect_pyodbc

lib/sqlalchemy/dialects/sybase/pysybase.py

@@ -0,0 +1,106 @@
+# sybase/pysybase.py
+# Copyright (C) 2010-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""
+.. dialect:: sybase+pysybase
+    :name: Python-Sybase
+    :dbapi: Sybase
+    :connectstring: sybase+pysybase://<username>:<password>@<dsn>/[database name]
+    :url: https://python-sybase.sourceforge.net/
+
+Unicode Support
+---------------
+
+The python-sybase driver does not appear to support non-ASCII strings of any
+kind at this time.
+
+"""  # noqa
+
+from sqlalchemy import processors
+from sqlalchemy import types as sqltypes
+from sqlalchemy.dialects.sybase.base import SybaseDialect
+from sqlalchemy.dialects.sybase.base import SybaseExecutionContext
+from sqlalchemy.dialects.sybase.base import SybaseSQLCompiler
+
+
+class _SybNumeric(sqltypes.Numeric):
+    def result_processor(self, dialect, type_):
+        if not self.asdecimal:
+            return processors.to_float
+        else:
+            return sqltypes.Numeric.result_processor(self, dialect, type_)
+
+
+class SybaseExecutionContext_pysybase(SybaseExecutionContext):
+    def set_ddl_autocommit(self, dbapi_connection, value):
+        if value:
+            # call commit() on the Sybase connection directly,
+            # to avoid any side effects of calling a Connection
+            # transactional method inside of pre_exec()
+            dbapi_connection.commit()
+
+    def pre_exec(self):
+        SybaseExecutionContext.pre_exec(self)
+
+        for param in self.parameters:
+            for key in list(param):
+                param["@" + key] = param[key]
+                del param[key]
+
+
+class SybaseSQLCompiler_pysybase(SybaseSQLCompiler):
+    def bindparam_string(self, name, **kw):
+        return "@" + name
+
+
+class SybaseDialect_pysybase(SybaseDialect):
+    driver = "pysybase"
+    execution_ctx_cls = SybaseExecutionContext_pysybase
+    statement_compiler = SybaseSQLCompiler_pysybase
+
+    supports_statement_cache = True
+
+    colspecs = {sqltypes.Numeric: _SybNumeric, sqltypes.Float: sqltypes.Float}
+
+    @classmethod
+    def dbapi(cls):
+        import Sybase
+
+        return Sybase
+
+    def create_connect_args(self, url):
+        opts = url.translate_connect_args(username="user", password="passwd")
+
+        return ([opts.pop("host")], opts)
+
+    def do_executemany(self, cursor, statement, parameters, context=None):
+        # calling python-sybase executemany yields:
+        # TypeError: string too long for buffer
+        for param in parameters:
+            cursor.execute(statement, param)
+
+    def _get_server_version_info(self, connection):
+        vers = connection.exec_driver_sql("select @@version_number").scalar()
+        # i.e. 15500, 15000, 12500 == (15, 5, 0, 0), (15, 0, 0, 0),
+        # (12, 5, 0, 0)
+        return (vers / 1000, vers % 1000 / 100, vers % 100 / 10, vers % 10)
+
+    def is_disconnect(self, e, connection, cursor):
+        if isinstance(
+            e, (self.dbapi.OperationalError, self.dbapi.ProgrammingError)
+        ):
+            msg = str(e)
+            return (
+                "Unable to complete network request to host" in msg
+                or "Invalid connection state" in msg
+                or "Invalid cursor state" in msg
+            )
+        else:
+            return False
+
+
+dialect = SybaseDialect_pysybase

lib/sqlalchemy/engine/__init__.py

@@ -0,0 +1,62 @@
+# engine/__init__.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""SQL connections, SQL execution and high-level DB-API interface.
+
+The engine package defines the basic components used to interface
+DB-API modules with higher-level statement construction,
+connection-management, execution and result contexts.  The primary
+"entry point" class into this package is the Engine and its public
+constructor ``create_engine()``.
+
+"""
+
+from . import events
+from . import util
+from .base import Connection
+from .base import Engine
+from .base import NestedTransaction
+from .base import RootTransaction
+from .base import Transaction
+from .base import TwoPhaseTransaction
+from .create import create_engine
+from .create import engine_from_config
+from .cursor import BaseCursorResult
+from .cursor import BufferedColumnResultProxy
+from .cursor import BufferedColumnRow
+from .cursor import BufferedRowResultProxy
+from .cursor import CursorResult
+from .cursor import FullyBufferedResultProxy
+from .cursor import LegacyCursorResult
+from .cursor import ResultProxy
+from .interfaces import AdaptedConnection
+from .interfaces import Compiled
+from .interfaces import Connectable
+from .interfaces import CreateEnginePlugin
+from .interfaces import Dialect
+from .interfaces import ExceptionContext
+from .interfaces import ExecutionContext
+from .interfaces import TypeCompiler
+from .mock import create_mock_engine
+from .reflection import Inspector
+from .result import ChunkedIteratorResult
+from .result import FilterResult
+from .result import FrozenResult
+from .result import IteratorResult
+from .result import MappingResult
+from .result import MergedResult
+from .result import Result
+from .result import result_tuple
+from .result import ScalarResult
+from .row import BaseRow
+from .row import LegacyRow
+from .row import Row
+from .row import RowMapping
+from .url import make_url
+from .url import URL
+from .util import connection_memoize
+from ..sql import ddl

lib/sqlalchemy/engine/characteristics.py

@@ -0,0 +1,56 @@
+import abc
+
+from ..util import ABC
+
+
+class ConnectionCharacteristic(ABC):
+    """An abstract base for an object that can set, get and reset a
+    per-connection characteristic, typically one that gets reset when the
+    connection is returned to the connection pool.
+
+    transaction isolation is the canonical example, and the
+    ``IsolationLevelCharacteristic`` implementation provides this for the
+    ``DefaultDialect``.
+
+    The ``ConnectionCharacteristic`` class should call upon the ``Dialect`` for
+    the implementation of each method.   The object exists strictly to serve as
+    a dialect visitor that can be placed into the
+    ``DefaultDialect.connection_characteristics`` dictionary where it will take
+    effect for calls to :meth:`_engine.Connection.execution_options` and
+    related APIs.
+
+    .. versionadded:: 1.4
+
+    """
+
+    __slots__ = ()
+
+    transactional = False
+
+    @abc.abstractmethod
+    def reset_characteristic(self, dialect, dbapi_conn):
+        """Reset the characteristic on the connection to its default value."""
+
+    @abc.abstractmethod
+    def set_characteristic(self, dialect, dbapi_conn, value):
+        """set characteristic on the connection to a given value."""
+
+    @abc.abstractmethod
+    def get_characteristic(self, dialect, dbapi_conn):
+        """Given a DBAPI connection, get the current value of the
+        characteristic.
+
+        """
+
+
+class IsolationLevelCharacteristic(ConnectionCharacteristic):
+    transactional = True
+
+    def reset_characteristic(self, dialect, dbapi_conn):
+        dialect.reset_isolation_level(dbapi_conn)
+
+    def set_characteristic(self, dialect, dbapi_conn, value):
+        dialect.set_isolation_level(dbapi_conn, value)
+
+    def get_characteristic(self, dialect, dbapi_conn):
+        return dialect.get_isolation_level(dbapi_conn)

lib/sqlalchemy/engine/create.py

@@ -0,0 +1,743 @@
+# engine/create.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+
+from . import base
+from . import url as _url
+from .mock import create_mock_engine
+from .. import event
+from .. import exc
+from .. import pool as poollib
+from .. import util
+from ..sql import compiler
+
+
+@util.deprecated_params(
+    strategy=(
+        "1.4",
+        "The :paramref:`_sa.create_engine.strategy` keyword is deprecated, "
+        "and the only argument accepted is 'mock'; please use "
+        ":func:`.create_mock_engine` going forward.  For general "
+        "customization of create_engine which may have been accomplished "
+        "using strategies, see :class:`.CreateEnginePlugin`.",
+    ),
+    empty_in_strategy=(
+        "1.4",
+        "The :paramref:`_sa.create_engine.empty_in_strategy` keyword is "
+        "deprecated, and no longer has any effect.  All IN expressions "
+        "are now rendered using "
+        'the "expanding parameter" strategy which renders a set of bound'
+        'expressions, or an "empty set" SELECT, at statement execution'
+        "time.",
+    ),
+    case_sensitive=(
+        "1.4",
+        "The :paramref:`_sa.create_engine.case_sensitive` parameter "
+        "is deprecated and will be removed in a future release. "
+        "Applications should work with result column names in a case "
+        "sensitive fashion.",
+    ),
+)
+def create_engine(url, **kwargs):
+    """Create a new :class:`_engine.Engine` instance.
+
+    The standard calling form is to send the :ref:`URL <database_urls>` as the
+    first positional argument, usually a string
+    that indicates database dialect and connection arguments::
+
+        engine = create_engine("postgresql://scott:tiger@localhost/test")
+
+    .. note::
+
+        Please review :ref:`database_urls` for general guidelines in composing
+        URL strings.  In particular, special characters, such as those often
+        part of passwords, must be URL encoded to be properly parsed.
+
+    Additional keyword arguments may then follow it which
+    establish various options on the resulting :class:`_engine.Engine`
+    and its underlying :class:`.Dialect` and :class:`_pool.Pool`
+    constructs::
+
+        engine = create_engine("mysql://scott:tiger@hostname/dbname",
+                                    encoding='latin1', echo=True)
+
+    The string form of the URL is
+    ``dialect[+driver]://user:password@host/dbname[?key=value..]``, where
+    ``dialect`` is a database name such as ``mysql``, ``oracle``,
+    ``postgresql``, etc., and ``driver`` the name of a DBAPI, such as
+    ``psycopg2``, ``pyodbc``, ``cx_oracle``, etc.  Alternatively,
+    the URL can be an instance of :class:`~sqlalchemy.engine.url.URL`.
+
+    ``**kwargs`` takes a wide variety of options which are routed
+    towards their appropriate components.  Arguments may be specific to
+    the :class:`_engine.Engine`, the underlying :class:`.Dialect`,
+    as well as the
+    :class:`_pool.Pool`.  Specific dialects also accept keyword arguments that
+    are unique to that dialect.   Here, we describe the parameters
+    that are common to most :func:`_sa.create_engine()` usage.
+
+    Once established, the newly resulting :class:`_engine.Engine` will
+    request a connection from the underlying :class:`_pool.Pool` once
+    :meth:`_engine.Engine.connect` is called, or a method which depends on it
+    such as :meth:`_engine.Engine.execute` is invoked.   The
+    :class:`_pool.Pool` in turn
+    will establish the first actual DBAPI connection when this request
+    is received.   The :func:`_sa.create_engine` call itself does **not**
+    establish any actual DBAPI connections directly.
+
+    .. seealso::
+
+        :doc:`/core/engines`
+
+        :doc:`/dialects/index`
+
+        :ref:`connections_toplevel`
+
+    :param case_sensitive: if False, result column names
+       will match in a case-insensitive fashion, that is,
+       ``row['SomeColumn']``.
+
+    :param connect_args: a dictionary of options which will be
+        passed directly to the DBAPI's ``connect()`` method as
+        additional keyword arguments.  See the example
+        at :ref:`custom_dbapi_args`.
+
+    :param convert_unicode=False: if set to True, causes
+        all :class:`.String` datatypes to act as though the
+        :paramref:`.String.convert_unicode` flag has been set to ``True``,
+        regardless of a setting of ``False`` on an individual :class:`.String`
+        type.  This has the effect of causing all :class:`.String` -based
+        columns to accommodate Python Unicode objects directly as though the
+        datatype were the :class:`.Unicode` type.
+
+        .. deprecated:: 1.3
+
+            The :paramref:`_sa.create_engine.convert_unicode` parameter
+            is deprecated and will be removed in a future release.
+            All modern DBAPIs now support Python Unicode directly and this
+            parameter is unnecessary.
+
+    :param creator: a callable which returns a DBAPI connection.
+        This creation function will be passed to the underlying
+        connection pool and will be used to create all new database
+        connections. Usage of this function causes connection
+        parameters specified in the URL argument to be bypassed.
+
+        This hook is not as flexible as the newer
+        :meth:`_events.DialectEvents.do_connect` hook which allows complete
+        control over how a connection is made to the database, given the full
+        set of URL arguments and state beforehand.
+
+        .. seealso::
+
+            :meth:`_events.DialectEvents.do_connect` - event hook that allows
+            full control over DBAPI connection mechanics.
+
+            :ref:`custom_dbapi_args`
+
+    :param echo=False: if True, the Engine will log all statements
+        as well as a ``repr()`` of their parameter lists to the default log
+        handler, which defaults to ``sys.stdout`` for output.   If set to the
+        string ``"debug"``, result rows will be printed to the standard output
+        as well. The ``echo`` attribute of ``Engine`` can be modified at any
+        time to turn logging on and off; direct control of logging is also
+        available using the standard Python ``logging`` module.
+
+        .. seealso::
+
+            :ref:`dbengine_logging` - further detail on how to configure
+            logging.
+
+
+    :param echo_pool=False: if True, the connection pool will log
+        informational output such as when connections are invalidated
+        as well as when connections are recycled to the default log handler,
+        which defaults to ``sys.stdout`` for output.   If set to the string
+        ``"debug"``, the logging will include pool checkouts and checkins.
+        Direct control of logging is also available using the standard Python
+        ``logging`` module.
+
+        .. seealso::
+
+            :ref:`dbengine_logging` - further detail on how to configure
+            logging.
+
+
+    :param empty_in_strategy:   No longer used; SQLAlchemy now uses
+        "empty set" behavior for IN in all cases.
+
+    :param enable_from_linting: defaults to True.  Will emit a warning
+        if a given SELECT statement is found to have un-linked FROM elements
+        which would cause a cartesian product.
+
+        .. versionadded:: 1.4
+
+        .. seealso::
+
+            :ref:`change_4737`
+
+    :param encoding: **legacy Python 2 value only, where it only applies to
+        specific DBAPIs, not used in Python 3 for any modern DBAPI driver.
+        Please refer to individual dialect documentation for client encoding
+        behaviors.**  Defaults to the string value ``utf-8``.  This value
+        refers **only** to the character encoding that is used when SQLAlchemy
+        sends or receives data from a :term:`DBAPI` that does not support
+        Python Unicode and **is only used under Python 2**, only for certain
+        DBAPI drivers, and only in certain circumstances. **Python 3 users
+        please DISREGARD this parameter and refer to the documentation for the
+        specific dialect in use in order to configure character encoding
+        behavior.**
+
+        .. note:: The ``encoding`` parameter deals only with in-Python
+           encoding issues that were prevalent with **some DBAPIS only**
+           under **Python 2 only**.  Under Python 3 it is not used by
+           any modern dialect. For  DBAPIs that require
+           client encoding configurations, which are most of those outside
+           of SQLite, please consult specific :ref:`dialect documentation
+           <dialect_toplevel>` for details.
+
+        All modern DBAPIs that work in Python 3 necessarily feature direct
+        support for Python unicode strings.   Under Python 2, this was not
+        always the case.  For those scenarios where the DBAPI is detected as
+        not supporting a Python ``unicode`` object under Python 2, this
+        encoding is used to determine the source/destination encoding.  It is
+        **not used** for those cases where the DBAPI handles unicode directly.
+
+        To properly configure a system to accommodate Python ``unicode``
+        objects, the DBAPI should be configured to handle unicode to the
+        greatest degree as is appropriate - see the notes on unicode pertaining
+        to the specific target database in use at :ref:`dialect_toplevel`.
+
+        Areas where string encoding may need to be accommodated
+        outside of the DBAPI, nearly always under **Python 2 only**,
+        include zero or more of:
+
+        * the values passed to bound parameters, corresponding to
+          the :class:`.Unicode` type or the :class:`.String` type
+          when ``convert_unicode`` is ``True``;
+        * the values returned in result set columns corresponding
+          to the :class:`.Unicode` type or the :class:`.String`
+          type when ``convert_unicode`` is ``True``;
+        * the string SQL statement passed to the DBAPI's
+          ``cursor.execute()`` method;
+        * the string names of the keys in the bound parameter
+          dictionary passed to the DBAPI's ``cursor.execute()``
+          as well as ``cursor.setinputsizes()`` methods;
+        * the string column names retrieved from the DBAPI's
+          ``cursor.description`` attribute.
+
+        When using Python 3, the DBAPI is required to support all of the above
+        values as Python ``unicode`` objects, which in Python 3 are just known
+        as ``str``.  In Python 2, the DBAPI does not specify unicode behavior
+        at all, so SQLAlchemy must make decisions for each of the above values
+        on a per-DBAPI basis - implementations are completely inconsistent in
+        their behavior.
+
+    :param execution_options: Dictionary execution options which will
+        be applied to all connections.  See
+        :meth:`~sqlalchemy.engine.Connection.execution_options`
+
+    :param future: Use the 2.0 style :class:`_future.Engine` and
+        :class:`_future.Connection` API.
+
+        .. versionadded:: 1.4
+
+        .. seealso::
+
+            :ref:`migration_20_toplevel`
+
+    :param hide_parameters: Boolean, when set to True, SQL statement parameters
+        will not be displayed in INFO logging nor will they be formatted into
+        the string representation of :class:`.StatementError` objects.
+
+        .. versionadded:: 1.3.8
+
+        .. seealso::
+
+            :ref:`dbengine_logging` - further detail on how to configure
+            logging.
+
+    :param implicit_returning=True:  Legacy flag that when set to ``False``
+        will disable the use of ``RETURNING`` on supporting backends where it
+        would normally be used to fetch newly generated primary key values for
+        single-row INSERT statements that do not otherwise specify a RETURNING
+        clause.  This behavior applies primarily to the PostgreSQL, Oracle,
+        SQL Server backends.
+
+        .. warning:: this flag originally allowed the "implicit returning"
+           feature to be *enabled* back when it was very new and there was not
+           well-established database support.  In modern SQLAlchemy, this flag
+           should **always be set to True**.  Some SQLAlchemy features will
+           fail to function properly if this flag is set to ``False``.
+
+    :param isolation_level: this string parameter is interpreted by various
+        dialects in order to affect the transaction isolation level of the
+        database connection.   The parameter essentially accepts some subset of
+        these string arguments: ``"SERIALIZABLE"``, ``"REPEATABLE READ"``,
+        ``"READ COMMITTED"``, ``"READ UNCOMMITTED"`` and ``"AUTOCOMMIT"``.
+        Behavior here varies per backend, and
+        individual dialects should be consulted directly.
+
+        Note that the isolation level can also be set on a
+        per-:class:`_engine.Connection` basis as well, using the
+        :paramref:`.Connection.execution_options.isolation_level`
+        feature.
+
+        .. seealso::
+
+            :ref:`dbapi_autocommit`
+
+    :param json_deserializer: for dialects that support the
+        :class:`_types.JSON`
+        datatype, this is a Python callable that will convert a JSON string
+        to a Python object.  By default, the Python ``json.loads`` function is
+        used.
+
+        .. versionchanged:: 1.3.7  The SQLite dialect renamed this from
+           ``_json_deserializer``.
+
+    :param json_serializer: for dialects that support the :class:`_types.JSON`
+        datatype, this is a Python callable that will render a given object
+        as JSON.   By default, the Python ``json.dumps`` function is used.
+
+        .. versionchanged:: 1.3.7  The SQLite dialect renamed this from
+           ``_json_serializer``.
+
+
+    :param label_length=None: optional integer value which limits
+        the size of dynamically generated column labels to that many
+        characters. If less than 6, labels are generated as
+        "_(counter)". If ``None``, the value of
+        ``dialect.max_identifier_length``, which may be affected via the
+        :paramref:`_sa.create_engine.max_identifier_length` parameter,
+        is used instead.   The value of
+        :paramref:`_sa.create_engine.label_length`
+        may not be larger than that of
+        :paramref:`_sa.create_engine.max_identfier_length`.
+
+        .. seealso::
+
+            :paramref:`_sa.create_engine.max_identifier_length`
+
+    :param listeners: A list of one or more
+        :class:`~sqlalchemy.interfaces.PoolListener` objects which will
+        receive connection pool events.
+
+    :param logging_name:  String identifier which will be used within
+        the "name" field of logging records generated within the
+        "sqlalchemy.engine" logger. Defaults to a hexstring of the
+        object's id.
+
+        .. seealso::
+
+            :ref:`dbengine_logging` - further detail on how to configure
+            logging.
+
+            :paramref:`_engine.Connection.execution_options.logging_token`
+
+
+
+    :param max_identifier_length: integer; override the max_identifier_length
+        determined by the dialect.  if ``None`` or zero, has no effect.  This
+        is the database's configured maximum number of characters that may be
+        used in a SQL identifier such as a table name, column name, or label
+        name. All dialects determine this value automatically, however in the
+        case of a new database version for which this value has changed but
+        SQLAlchemy's dialect has not been adjusted, the value may be passed
+        here.
+
+        .. versionadded:: 1.3.9
+
+        .. seealso::
+
+            :paramref:`_sa.create_engine.label_length`
+
+    :param max_overflow=10: the number of connections to allow in
+        connection pool "overflow", that is connections that can be
+        opened above and beyond the pool_size setting, which defaults
+        to five. this is only used with :class:`~sqlalchemy.pool.QueuePool`.
+
+    :param module=None: reference to a Python module object (the module
+        itself, not its string name).  Specifies an alternate DBAPI module to
+        be used by the engine's dialect.  Each sub-dialect references a
+        specific DBAPI which will be imported before first connect.  This
+        parameter causes the import to be bypassed, and the given module to
+        be used instead. Can be used for testing of DBAPIs as well as to
+        inject "mock" DBAPI implementations into the :class:`_engine.Engine`.
+
+    :param paramstyle=None: The `paramstyle <https://legacy.python.org/dev/peps/pep-0249/#paramstyle>`_
+        to use when rendering bound parameters.  This style defaults to the
+        one recommended by the DBAPI itself, which is retrieved from the
+        ``.paramstyle`` attribute of the DBAPI.  However, most DBAPIs accept
+        more than one paramstyle, and in particular it may be desirable
+        to change a "named" paramstyle into a "positional" one, or vice versa.
+        When this attribute is passed, it should be one of the values
+        ``"qmark"``, ``"numeric"``, ``"named"``, ``"format"`` or
+        ``"pyformat"``, and should correspond to a parameter style known
+        to be supported by the DBAPI in use.
+
+    :param pool=None: an already-constructed instance of
+        :class:`~sqlalchemy.pool.Pool`, such as a
+        :class:`~sqlalchemy.pool.QueuePool` instance. If non-None, this
+        pool will be used directly as the underlying connection pool
+        for the engine, bypassing whatever connection parameters are
+        present in the URL argument. For information on constructing
+        connection pools manually, see :ref:`pooling_toplevel`.
+
+    :param poolclass=None: a :class:`~sqlalchemy.pool.Pool`
+        subclass, which will be used to create a connection pool
+        instance using the connection parameters given in the URL. Note
+        this differs from ``pool`` in that you don't actually
+        instantiate the pool in this case, you just indicate what type
+        of pool to be used.
+
+    :param pool_logging_name:  String identifier which will be used within
+       the "name" field of logging records generated within the
+       "sqlalchemy.pool" logger. Defaults to a hexstring of the object's
+       id.
+
+
+       .. seealso::
+
+            :ref:`dbengine_logging` - further detail on how to configure
+            logging.
+
+
+    :param pool_pre_ping: boolean, if True will enable the connection pool
+        "pre-ping" feature that tests connections for liveness upon
+        each checkout.
+
+        .. versionadded:: 1.2
+
+        .. seealso::
+
+            :ref:`pool_disconnects_pessimistic`
+
+    :param pool_size=5: the number of connections to keep open
+        inside the connection pool. This used with
+        :class:`~sqlalchemy.pool.QueuePool` as
+        well as :class:`~sqlalchemy.pool.SingletonThreadPool`.  With
+        :class:`~sqlalchemy.pool.QueuePool`, a ``pool_size`` setting
+        of 0 indicates no limit; to disable pooling, set ``poolclass`` to
+        :class:`~sqlalchemy.pool.NullPool` instead.
+
+    :param pool_recycle=-1: this setting causes the pool to recycle
+        connections after the given number of seconds has passed. It
+        defaults to -1, or no timeout. For example, setting to 3600
+        means connections will be recycled after one hour. Note that
+        MySQL in particular will disconnect automatically if no
+        activity is detected on a connection for eight hours (although
+        this is configurable with the MySQLDB connection itself and the
+        server configuration as well).
+
+        .. seealso::
+
+            :ref:`pool_setting_recycle`
+
+    :param pool_reset_on_return='rollback': set the
+        :paramref:`_pool.Pool.reset_on_return` parameter of the underlying
+        :class:`_pool.Pool` object, which can be set to the values
+        ``"rollback"``, ``"commit"``, or ``None``.
+
+        .. seealso::
+
+            :paramref:`_pool.Pool.reset_on_return`
+
+    :param pool_timeout=30: number of seconds to wait before giving
+        up on getting a connection from the pool. This is only used
+        with :class:`~sqlalchemy.pool.QueuePool`. This can be a float but is
+        subject to the limitations of Python time functions which may not be
+        reliable in the tens of milliseconds.
+
+        .. note: don't use 30.0 above, it seems to break with the :param tag
+
+    :param pool_use_lifo=False: use LIFO (last-in-first-out) when retrieving
+        connections from :class:`.QueuePool` instead of FIFO
+        (first-in-first-out). Using LIFO, a server-side timeout scheme can
+        reduce the number of connections used during non- peak   periods of
+        use.   When planning for server-side timeouts, ensure that a recycle or
+        pre-ping strategy is in use to gracefully   handle stale connections.
+
+          .. versionadded:: 1.3
+
+          .. seealso::
+
+            :ref:`pool_use_lifo`
+
+            :ref:`pool_disconnects`
+
+    :param plugins: string list of plugin names to load.  See
+        :class:`.CreateEnginePlugin` for background.
+
+        .. versionadded:: 1.2.3
+
+    :param query_cache_size: size of the cache used to cache the SQL string
+     form of queries.  Set to zero to disable caching.
+
+     The cache is pruned of its least recently used items when its size reaches
+     N * 1.5.  Defaults to 500, meaning the cache will always store at least
+     500 SQL statements when filled, and will grow up to 750 items at which
+     point it is pruned back down to 500 by removing the 250 least recently
+     used items.
+
+     Caching is accomplished on a per-statement basis by generating a
+     cache key that represents the statement's structure, then generating
+     string SQL for the current dialect only if that key is not present
+     in the cache.   All statements support caching, however some features
+     such as an INSERT with a large set of parameters will intentionally
+     bypass the cache.   SQL logging will indicate statistics for each
+     statement whether or not it were pull from the cache.
+
+     .. note:: some ORM functions related to unit-of-work persistence as well
+        as some attribute loading strategies will make use of individual
+        per-mapper caches outside of the main cache.
+
+
+     .. seealso::
+
+        :ref:`sql_caching`
+
+     .. versionadded:: 1.4
+
+    """  # noqa
+
+    if "strategy" in kwargs:
+        strat = kwargs.pop("strategy")
+        if strat == "mock":
+            return create_mock_engine(url, **kwargs)
+        else:
+            raise exc.ArgumentError("unknown strategy: %r" % strat)
+
+    kwargs.pop("empty_in_strategy", None)
+
+    # create url.URL object
+    u = _url.make_url(url)
+
+    u, plugins, kwargs = u._instantiate_plugins(kwargs)
+
+    entrypoint = u._get_entrypoint()
+    dialect_cls = entrypoint.get_dialect_cls(u)
+
+    if kwargs.pop("_coerce_config", False):
+
+        def pop_kwarg(key, default=None):
+            value = kwargs.pop(key, default)
+            if key in dialect_cls.engine_config_types:
+                value = dialect_cls.engine_config_types[key](value)
+            return value
+
+    else:
+        pop_kwarg = kwargs.pop
+
+    dialect_args = {}
+    # consume dialect arguments from kwargs
+    for k in util.get_cls_kwargs(dialect_cls):
+        if k in kwargs:
+            dialect_args[k] = pop_kwarg(k)
+
+    dbapi = kwargs.pop("module", None)
+    if dbapi is None:
+        dbapi_args = {}
+        for k in util.get_func_kwargs(dialect_cls.dbapi):
+            if k in kwargs:
+                dbapi_args[k] = pop_kwarg(k)
+        dbapi = dialect_cls.dbapi(**dbapi_args)
+
+    dialect_args["dbapi"] = dbapi
+
+    dialect_args.setdefault("compiler_linting", compiler.NO_LINTING)
+    enable_from_linting = kwargs.pop("enable_from_linting", True)
+    if enable_from_linting:
+        dialect_args["compiler_linting"] ^= compiler.COLLECT_CARTESIAN_PRODUCTS
+
+    for plugin in plugins:
+        plugin.handle_dialect_kwargs(dialect_cls, dialect_args)
+
+    # create dialect
+    dialect = dialect_cls(**dialect_args)
+
+    # assemble connection arguments
+    (cargs, cparams) = dialect.create_connect_args(u)
+    cparams.update(pop_kwarg("connect_args", {}))
+    cargs = list(cargs)  # allow mutability
+
+    # look for existing pool or create
+    pool = pop_kwarg("pool", None)
+    if pool is None:
+
+        def connect(connection_record=None):
+            if dialect._has_events:
+                for fn in dialect.dispatch.do_connect:
+                    connection = fn(dialect, connection_record, cargs, cparams)
+                    if connection is not None:
+                        return connection
+            return dialect.connect(*cargs, **cparams)
+
+        creator = pop_kwarg("creator", connect)
+
+        poolclass = pop_kwarg("poolclass", None)
+        if poolclass is None:
+            poolclass = dialect.get_dialect_pool_class(u)
+        pool_args = {"dialect": dialect}
+
+        # consume pool arguments from kwargs, translating a few of
+        # the arguments
+        translate = {
+            "logging_name": "pool_logging_name",
+            "echo": "echo_pool",
+            "timeout": "pool_timeout",
+            "recycle": "pool_recycle",
+            "events": "pool_events",
+            "reset_on_return": "pool_reset_on_return",
+            "pre_ping": "pool_pre_ping",
+            "use_lifo": "pool_use_lifo",
+        }
+        for k in util.get_cls_kwargs(poolclass):
+            tk = translate.get(k, k)
+            if tk in kwargs:
+                pool_args[k] = pop_kwarg(tk)
+
+        for plugin in plugins:
+            plugin.handle_pool_kwargs(poolclass, pool_args)
+
+        pool = poolclass(creator, **pool_args)
+    else:
+        if isinstance(pool, poollib.dbapi_proxy._DBProxy):
+            pool = pool.get_pool(*cargs, **cparams)
+
+        pool._dialect = dialect
+
+    # create engine.
+    if pop_kwarg("future", False):
+        from sqlalchemy import future
+
+        default_engine_class = future.Engine
+    else:
+        default_engine_class = base.Engine
+
+    engineclass = kwargs.pop("_future_engine_class", default_engine_class)
+
+    engine_args = {}
+    for k in util.get_cls_kwargs(engineclass):
+        if k in kwargs:
+            engine_args[k] = pop_kwarg(k)
+
+    # internal flags used by the test suite for instrumenting / proxying
+    # engines with mocks etc.
+    _initialize = kwargs.pop("_initialize", True)
+    _wrap_do_on_connect = kwargs.pop("_wrap_do_on_connect", None)
+
+    # all kwargs should be consumed
+    if kwargs:
+        raise TypeError(
+            "Invalid argument(s) %s sent to create_engine(), "
+            "using configuration %s/%s/%s.  Please check that the "
+            "keyword arguments are appropriate for this combination "
+            "of components."
+            % (
+                ",".join("'%s'" % k for k in kwargs),
+                dialect.__class__.__name__,
+                pool.__class__.__name__,
+                engineclass.__name__,
+            )
+        )
+
+    engine = engineclass(pool, dialect, u, **engine_args)
+
+    if _initialize:
+        do_on_connect = dialect.on_connect_url(u)
+        if do_on_connect:
+            if _wrap_do_on_connect:
+                do_on_connect = _wrap_do_on_connect(do_on_connect)
+
+            def on_connect(dbapi_connection, connection_record):
+                do_on_connect(dbapi_connection)
+
+            event.listen(pool, "connect", on_connect)
+
+        def first_connect(dbapi_connection, connection_record):
+            c = base.Connection(
+                engine,
+                connection=dbapi_connection,
+                _has_events=False,
+                # reconnecting will be a reentrant condition, so if the
+                # connection goes away, Connection is then closed
+                _allow_revalidate=False,
+            )
+            c._execution_options = util.EMPTY_DICT
+
+            try:
+                dialect.initialize(c)
+            finally:
+                # note that "invalidated" and "closed" are mutually
+                # exclusive in 1.4 Connection.
+                if not c.invalidated and not c.closed:
+                    # transaction is rolled back otherwise, tested by
+                    # test/dialect/postgresql/test_dialect.py
+                    # ::MiscBackendTest::test_initial_transaction_state
+                    dialect.do_rollback(c.connection)
+
+        # previously, the "first_connect" event was used here, which was then
+        # scaled back if the "on_connect" handler were present.  now,
+        # since "on_connect" is virtually always present, just use
+        # "connect" event with once_unless_exception in all cases so that
+        # the connection event flow is consistent in all cases.
+        event.listen(
+            pool, "connect", first_connect, _once_unless_exception=True
+        )
+
+    dialect_cls.engine_created(engine)
+    if entrypoint is not dialect_cls:
+        entrypoint.engine_created(engine)
+
+    for plugin in plugins:
+        plugin.engine_created(engine)
+
+    return engine
+
+
+def engine_from_config(configuration, prefix="sqlalchemy.", **kwargs):
+    """Create a new Engine instance using a configuration dictionary.
+
+    The dictionary is typically produced from a config file.
+
+    The keys of interest to ``engine_from_config()`` should be prefixed, e.g.
+    ``sqlalchemy.url``, ``sqlalchemy.echo``, etc.  The 'prefix' argument
+    indicates the prefix to be searched for.  Each matching key (after the
+    prefix is stripped) is treated as though it were the corresponding keyword
+    argument to a :func:`_sa.create_engine` call.
+
+    The only required key is (assuming the default prefix) ``sqlalchemy.url``,
+    which provides the :ref:`database URL <database_urls>`.
+
+    A select set of keyword arguments will be "coerced" to their
+    expected type based on string values.    The set of arguments
+    is extensible per-dialect using the ``engine_config_types`` accessor.
+
+    :param configuration: A dictionary (typically produced from a config file,
+        but this is not a requirement).  Items whose keys start with the value
+        of 'prefix' will have that prefix stripped, and will then be passed to
+        :func:`_sa.create_engine`.
+
+    :param prefix: Prefix to match and then strip from keys
+        in 'configuration'.
+
+    :param kwargs: Each keyword argument to ``engine_from_config()`` itself
+        overrides the corresponding item taken from the 'configuration'
+        dictionary.  Keyword arguments should *not* be prefixed.
+
+    """
+
+    options = dict(
+        (key[len(prefix) :], configuration[key])
+        for key in configuration
+        if key.startswith(prefix)
+    )
+    options["_coerce_config"] = True
+    options.update(kwargs)
+    url = options.pop("url")
+    return create_engine(url, **options)

lib/sqlalchemy/engine/events.py

@@ -0,0 +1,835 @@
+# sqlalchemy/engine/events.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+
+from .base import Engine
+from .interfaces import Connectable
+from .interfaces import Dialect
+from .. import event
+from .. import exc
+
+
+class ConnectionEvents(event.Events):
+    """Available events for :class:`.Connectable`, which includes
+    :class:`_engine.Connection` and :class:`_engine.Engine`.
+
+    The methods here define the name of an event as well as the names of
+    members that are passed to listener functions.
+
+    An event listener can be associated with any :class:`.Connectable`
+    class or instance, such as an :class:`_engine.Engine`, e.g.::
+
+        from sqlalchemy import event, create_engine
+
+        def before_cursor_execute(conn, cursor, statement, parameters, context,
+                                                        executemany):
+            log.info("Received statement: %s", statement)
+
+        engine = create_engine('postgresql://scott:tiger@localhost/test')
+        event.listen(engine, "before_cursor_execute", before_cursor_execute)
+
+    or with a specific :class:`_engine.Connection`::
+
+        with engine.begin() as conn:
+            @event.listens_for(conn, 'before_cursor_execute')
+            def before_cursor_execute(conn, cursor, statement, parameters,
+                                            context, executemany):
+                log.info("Received statement: %s", statement)
+
+    When the methods are called with a `statement` parameter, such as in
+    :meth:`.after_cursor_execute` or :meth:`.before_cursor_execute`,
+    the statement is the exact SQL string that was prepared for transmission
+    to the DBAPI ``cursor`` in the connection's :class:`.Dialect`.
+
+    The :meth:`.before_execute` and :meth:`.before_cursor_execute`
+    events can also be established with the ``retval=True`` flag, which
+    allows modification of the statement and parameters to be sent
+    to the database.  The :meth:`.before_cursor_execute` event is
+    particularly useful here to add ad-hoc string transformations, such
+    as comments, to all executions::
+
+        from sqlalchemy.engine import Engine
+        from sqlalchemy import event
+
+        @event.listens_for(Engine, "before_cursor_execute", retval=True)
+        def comment_sql_calls(conn, cursor, statement, parameters,
+                                            context, executemany):
+            statement = statement + " -- some comment"
+            return statement, parameters
+
+    .. note:: :class:`_events.ConnectionEvents` can be established on any
+       combination of :class:`_engine.Engine`, :class:`_engine.Connection`,
+       as well
+       as instances of each of those classes.  Events across all
+       four scopes will fire off for a given instance of
+       :class:`_engine.Connection`.  However, for performance reasons, the
+       :class:`_engine.Connection` object determines at instantiation time
+       whether or not its parent :class:`_engine.Engine` has event listeners
+       established.   Event listeners added to the :class:`_engine.Engine`
+       class or to an instance of :class:`_engine.Engine`
+       *after* the instantiation
+       of a dependent :class:`_engine.Connection` instance will usually
+       *not* be available on that :class:`_engine.Connection` instance.
+       The newly
+       added listeners will instead take effect for
+       :class:`_engine.Connection`
+       instances created subsequent to those event listeners being
+       established on the parent :class:`_engine.Engine` class or instance.
+
+    :param retval=False: Applies to the :meth:`.before_execute` and
+      :meth:`.before_cursor_execute` events only.  When True, the
+      user-defined event function must have a return value, which
+      is a tuple of parameters that replace the given statement
+      and parameters.  See those methods for a description of
+      specific return arguments.
+
+    """
+
+    _target_class_doc = "SomeEngine"
+    _dispatch_target = Connectable
+
+    @classmethod
+    def _listen(cls, event_key, retval=False):
+        target, identifier, fn = (
+            event_key.dispatch_target,
+            event_key.identifier,
+            event_key._listen_fn,
+        )
+
+        target._has_events = True
+
+        if not retval:
+            if identifier == "before_execute":
+                orig_fn = fn
+
+                def wrap_before_execute(
+                    conn, clauseelement, multiparams, params, execution_options
+                ):
+                    orig_fn(
+                        conn,
+                        clauseelement,
+                        multiparams,
+                        params,
+                        execution_options,
+                    )
+                    return clauseelement, multiparams, params
+
+                fn = wrap_before_execute
+            elif identifier == "before_cursor_execute":
+                orig_fn = fn
+
+                def wrap_before_cursor_execute(
+                    conn, cursor, statement, parameters, context, executemany
+                ):
+                    orig_fn(
+                        conn,
+                        cursor,
+                        statement,
+                        parameters,
+                        context,
+                        executemany,
+                    )
+                    return statement, parameters
+
+                fn = wrap_before_cursor_execute
+        elif retval and identifier not in (
+            "before_execute",
+            "before_cursor_execute",
+            "handle_error",
+        ):
+            raise exc.ArgumentError(
+                "Only the 'before_execute', "
+                "'before_cursor_execute' and 'handle_error' engine "
+                "event listeners accept the 'retval=True' "
+                "argument."
+            )
+        event_key.with_wrapper(fn).base_listen()
+
+    @event._legacy_signature(
+        "1.4",
+        ["conn", "clauseelement", "multiparams", "params"],
+        lambda conn, clauseelement, multiparams, params, execution_options: (
+            conn,
+            clauseelement,
+            multiparams,
+            params,
+        ),
+    )
+    def before_execute(
+        self, conn, clauseelement, multiparams, params, execution_options
+    ):
+        """Intercept high level execute() events, receiving uncompiled
+        SQL constructs and other objects prior to rendering into SQL.
+
+        This event is good for debugging SQL compilation issues as well
+        as early manipulation of the parameters being sent to the database,
+        as the parameter lists will be in a consistent format here.
+
+        This event can be optionally established with the ``retval=True``
+        flag.  The ``clauseelement``, ``multiparams``, and ``params``
+        arguments should be returned as a three-tuple in this case::
+
+            @event.listens_for(Engine, "before_execute", retval=True)
+            def before_execute(conn, clauseelement, multiparams, params):
+                # do something with clauseelement, multiparams, params
+                return clauseelement, multiparams, params
+
+        :param conn: :class:`_engine.Connection` object
+        :param clauseelement: SQL expression construct, :class:`.Compiled`
+         instance, or string statement passed to
+         :meth:`_engine.Connection.execute`.
+        :param multiparams: Multiple parameter sets, a list of dictionaries.
+        :param params: Single parameter set, a single dictionary.
+        :param execution_options: dictionary of execution
+         options passed along with the statement, if any.  This is a merge
+         of all options that will be used, including those of the statement,
+         the connection, and those passed in to the method itself for
+         the 2.0 style of execution.
+
+         .. versionadded: 1.4
+
+        .. seealso::
+
+            :meth:`.before_cursor_execute`
+
+        """
+
+    @event._legacy_signature(
+        "1.4",
+        ["conn", "clauseelement", "multiparams", "params", "result"],
+        lambda conn, clauseelement, multiparams, params, execution_options, result: (  # noqa
+            conn,
+            clauseelement,
+            multiparams,
+            params,
+            result,
+        ),
+    )
+    def after_execute(
+        self,
+        conn,
+        clauseelement,
+        multiparams,
+        params,
+        execution_options,
+        result,
+    ):
+        """Intercept high level execute() events after execute.
+
+
+        :param conn: :class:`_engine.Connection` object
+        :param clauseelement: SQL expression construct, :class:`.Compiled`
+         instance, or string statement passed to
+         :meth:`_engine.Connection.execute`.
+        :param multiparams: Multiple parameter sets, a list of dictionaries.
+        :param params: Single parameter set, a single dictionary.
+        :param execution_options: dictionary of execution
+         options passed along with the statement, if any.  This is a merge
+         of all options that will be used, including those of the statement,
+         the connection, and those passed in to the method itself for
+         the 2.0 style of execution.
+
+         .. versionadded: 1.4
+
+        :param result: :class:`_engine.CursorResult` generated by the
+         execution.
+
+        """
+
+    def before_cursor_execute(
+        self, conn, cursor, statement, parameters, context, executemany
+    ):
+        """Intercept low-level cursor execute() events before execution,
+        receiving the string SQL statement and DBAPI-specific parameter list to
+        be invoked against a cursor.
+
+        This event is a good choice for logging as well as late modifications
+        to the SQL string.  It's less ideal for parameter modifications except
+        for those which are specific to a target backend.
+
+        This event can be optionally established with the ``retval=True``
+        flag.  The ``statement`` and ``parameters`` arguments should be
+        returned as a two-tuple in this case::
+
+            @event.listens_for(Engine, "before_cursor_execute", retval=True)
+            def before_cursor_execute(conn, cursor, statement,
+                            parameters, context, executemany):
+                # do something with statement, parameters
+                return statement, parameters
+
+        See the example at :class:`_events.ConnectionEvents`.
+
+        :param conn: :class:`_engine.Connection` object
+        :param cursor: DBAPI cursor object
+        :param statement: string SQL statement, as to be passed to the DBAPI
+        :param parameters: Dictionary, tuple, or list of parameters being
+         passed to the ``execute()`` or ``executemany()`` method of the
+         DBAPI ``cursor``.  In some cases may be ``None``.
+        :param context: :class:`.ExecutionContext` object in use.  May
+         be ``None``.
+        :param executemany: boolean, if ``True``, this is an ``executemany()``
+         call, if ``False``, this is an ``execute()`` call.
+
+        .. seealso::
+
+            :meth:`.before_execute`
+
+            :meth:`.after_cursor_execute`
+
+        """
+
+    def after_cursor_execute(
+        self, conn, cursor, statement, parameters, context, executemany
+    ):
+        """Intercept low-level cursor execute() events after execution.
+
+        :param conn: :class:`_engine.Connection` object
+        :param cursor: DBAPI cursor object.  Will have results pending
+         if the statement was a SELECT, but these should not be consumed
+         as they will be needed by the :class:`_engine.CursorResult`.
+        :param statement: string SQL statement, as passed to the DBAPI
+        :param parameters: Dictionary, tuple, or list of parameters being
+         passed to the ``execute()`` or ``executemany()`` method of the
+         DBAPI ``cursor``.  In some cases may be ``None``.
+        :param context: :class:`.ExecutionContext` object in use.  May
+         be ``None``.
+        :param executemany: boolean, if ``True``, this is an ``executemany()``
+         call, if ``False``, this is an ``execute()`` call.
+
+        """
+
+    def handle_error(self, exception_context):
+        r"""Intercept all exceptions processed by the
+        :class:`_engine.Connection`.
+
+        This includes all exceptions emitted by the DBAPI as well as
+        within SQLAlchemy's statement invocation process, including
+        encoding errors and other statement validation errors.  Other areas
+        in which the event is invoked include transaction begin and end,
+        result row fetching, cursor creation.
+
+        Note that :meth:`.handle_error` may support new kinds of exceptions
+        and new calling scenarios at *any time*.  Code which uses this
+        event must expect new calling patterns to be present in minor
+        releases.
+
+        To support the wide variety of members that correspond to an exception,
+        as well as to allow extensibility of the event without backwards
+        incompatibility, the sole argument received is an instance of
+        :class:`.ExceptionContext`.   This object contains data members
+        representing detail about the exception.
+
+        Use cases supported by this hook include:
+
+        * read-only, low-level exception handling for logging and
+          debugging purposes
+        * exception re-writing
+        * Establishing or disabling whether a connection or the owning
+          connection pool is invalidated or expired in response to a
+          specific exception [1]_.
+
+        The hook is called while the cursor from the failed operation
+        (if any) is still open and accessible.   Special cleanup operations
+        can be called on this cursor; SQLAlchemy will attempt to close
+        this cursor subsequent to this hook being invoked.  If the connection
+        is in "autocommit" mode, the transaction also remains open within
+        the scope of this hook; the rollback of the per-statement transaction
+        also occurs after the hook is called.
+
+        .. note::
+
+            .. [1] The pool "pre_ping" handler enabled using the
+                :paramref:`_sa.create_engine.pool_pre_ping` parameter does
+                **not** consult this event before deciding if the "ping"
+                returned false, as opposed to receiving an unhandled error.
+                For this use case, the :ref:`legacy recipe based on
+                engine_connect() may be used
+                <pool_disconnects_pessimistic_custom>`.  A future API allow
+                more comprehensive customization of the "disconnect"
+                detection mechanism across all functions.
+
+        A handler function has two options for replacing
+        the SQLAlchemy-constructed exception into one that is user
+        defined.   It can either raise this new exception directly, in
+        which case all further event listeners are bypassed and the
+        exception will be raised, after appropriate cleanup as taken
+        place::
+
+            @event.listens_for(Engine, "handle_error")
+            def handle_exception(context):
+                if isinstance(context.original_exception,
+                    psycopg2.OperationalError) and \
+                    "failed" in str(context.original_exception):
+                    raise MySpecialException("failed operation")
+
+        .. warning::  Because the
+           :meth:`_events.ConnectionEvents.handle_error`
+           event specifically provides for exceptions to be re-thrown as
+           the ultimate exception raised by the failed statement,
+           **stack traces will be misleading** if the user-defined event
+           handler itself fails and throws an unexpected exception;
+           the stack trace may not illustrate the actual code line that
+           failed!  It is advised to code carefully here and use
+           logging and/or inline debugging if unexpected exceptions are
+           occurring.
+
+        Alternatively, a "chained" style of event handling can be
+        used, by configuring the handler with the ``retval=True``
+        modifier and returning the new exception instance from the
+        function.  In this case, event handling will continue onto the
+        next handler.   The "chained" exception is available using
+        :attr:`.ExceptionContext.chained_exception`::
+
+            @event.listens_for(Engine, "handle_error", retval=True)
+            def handle_exception(context):
+                if context.chained_exception is not None and \
+                    "special" in context.chained_exception.message:
+                    return MySpecialException("failed",
+                        cause=context.chained_exception)
+
+        Handlers that return ``None`` may be used within the chain; when
+        a handler returns ``None``, the previous exception instance,
+        if any, is maintained as the current exception that is passed onto the
+        next handler.
+
+        When a custom exception is raised or returned, SQLAlchemy raises
+        this new exception as-is, it is not wrapped by any SQLAlchemy
+        object.  If the exception is not a subclass of
+        :class:`sqlalchemy.exc.StatementError`,
+        certain features may not be available; currently this includes
+        the ORM's feature of adding a detail hint about "autoflush" to
+        exceptions raised within the autoflush process.
+
+        :param context: an :class:`.ExceptionContext` object.  See this
+         class for details on all available members.
+
+        .. versionadded:: 0.9.7 Added the
+            :meth:`_events.ConnectionEvents.handle_error` hook.
+
+        .. versionchanged:: 1.1 The :meth:`.handle_error` event will now
+           receive all exceptions that inherit from ``BaseException``,
+           including ``SystemExit`` and ``KeyboardInterrupt``.  The setting for
+           :attr:`.ExceptionContext.is_disconnect` is ``True`` in this case and
+           the default for
+           :attr:`.ExceptionContext.invalidate_pool_on_disconnect` is
+           ``False``.
+
+        .. versionchanged:: 1.0.0 The :meth:`.handle_error` event is now
+           invoked when an :class:`_engine.Engine` fails during the initial
+           call to :meth:`_engine.Engine.connect`, as well as when a
+           :class:`_engine.Connection` object encounters an error during a
+           reconnect operation.
+
+        .. versionchanged:: 1.0.0 The :meth:`.handle_error` event is
+           not fired off when a dialect makes use of the
+           ``skip_user_error_events`` execution option.   This is used
+           by dialects which intend to catch SQLAlchemy-specific exceptions
+           within specific operations, such as when the MySQL dialect detects
+           a table not present within the ``has_table()`` dialect method.
+           Prior to 1.0.0, code which implements :meth:`.handle_error` needs
+           to ensure that exceptions thrown in these scenarios are re-raised
+           without modification.
+
+        """
+
+    def engine_connect(self, conn, branch):
+        """Intercept the creation of a new :class:`_engine.Connection`.
+
+        This event is called typically as the direct result of calling
+        the :meth:`_engine.Engine.connect` method.
+
+        It differs from the :meth:`_events.PoolEvents.connect` method, which
+        refers to the actual connection to a database at the DBAPI level;
+        a DBAPI connection may be pooled and reused for many operations.
+        In contrast, this event refers only to the production of a higher level
+        :class:`_engine.Connection` wrapper around such a DBAPI connection.
+
+        It also differs from the :meth:`_events.PoolEvents.checkout` event
+        in that it is specific to the :class:`_engine.Connection` object,
+        not the
+        DBAPI connection that :meth:`_events.PoolEvents.checkout` deals with,
+        although
+        this DBAPI connection is available here via the
+        :attr:`_engine.Connection.connection` attribute.
+        But note there can in fact
+        be multiple :meth:`_events.PoolEvents.checkout`
+        events within the lifespan
+        of a single :class:`_engine.Connection` object, if that
+        :class:`_engine.Connection`
+        is invalidated and re-established.  There can also be multiple
+        :class:`_engine.Connection`
+        objects generated for the same already-checked-out
+        DBAPI connection, in the case that a "branch" of a
+        :class:`_engine.Connection`
+        is produced.
+
+        :param conn: :class:`_engine.Connection` object.
+        :param branch: if True, this is a "branch" of an existing
+         :class:`_engine.Connection`.  A branch is generated within the course
+         of a statement execution to invoke supplemental statements, most
+         typically to pre-execute a SELECT of a default value for the purposes
+         of an INSERT statement.
+
+        .. seealso::
+
+            :meth:`_events.PoolEvents.checkout`
+            the lower-level pool checkout event
+            for an individual DBAPI connection
+
+        """
+
+    def set_connection_execution_options(self, conn, opts):
+        """Intercept when the :meth:`_engine.Connection.execution_options`
+        method is called.
+
+        This method is called after the new :class:`_engine.Connection`
+        has been
+        produced, with the newly updated execution options collection, but
+        before the :class:`.Dialect` has acted upon any of those new options.
+
+        Note that this method is not called when a new
+        :class:`_engine.Connection`
+        is produced which is inheriting execution options from its parent
+        :class:`_engine.Engine`; to intercept this condition, use the
+        :meth:`_events.ConnectionEvents.engine_connect` event.
+
+        :param conn: The newly copied :class:`_engine.Connection` object
+
+        :param opts: dictionary of options that were passed to the
+         :meth:`_engine.Connection.execution_options` method.
+
+        .. versionadded:: 0.9.0
+
+        .. seealso::
+
+            :meth:`_events.ConnectionEvents.set_engine_execution_options`
+            - event
+            which is called when :meth:`_engine.Engine.execution_options`
+            is called.
+
+
+        """
+
+    def set_engine_execution_options(self, engine, opts):
+        """Intercept when the :meth:`_engine.Engine.execution_options`
+        method is called.
+
+        The :meth:`_engine.Engine.execution_options` method produces a shallow
+        copy of the :class:`_engine.Engine` which stores the new options.
+        That new
+        :class:`_engine.Engine` is passed here.
+        A particular application of this
+        method is to add a :meth:`_events.ConnectionEvents.engine_connect`
+        event
+        handler to the given :class:`_engine.Engine`
+        which will perform some per-
+        :class:`_engine.Connection` task specific to these execution options.
+
+        :param conn: The newly copied :class:`_engine.Engine` object
+
+        :param opts: dictionary of options that were passed to the
+         :meth:`_engine.Connection.execution_options` method.
+
+        .. versionadded:: 0.9.0
+
+        .. seealso::
+
+            :meth:`_events.ConnectionEvents.set_connection_execution_options`
+            - event
+            which is called when :meth:`_engine.Connection.execution_options`
+            is
+            called.
+
+        """
+
+    def engine_disposed(self, engine):
+        """Intercept when the :meth:`_engine.Engine.dispose` method is called.
+
+        The :meth:`_engine.Engine.dispose` method instructs the engine to
+        "dispose" of it's connection pool (e.g. :class:`_pool.Pool`), and
+        replaces it with a new one.  Disposing of the old pool has the
+        effect that existing checked-in connections are closed.  The new
+        pool does not establish any new connections until it is first used.
+
+        This event can be used to indicate that resources related to the
+        :class:`_engine.Engine` should also be cleaned up,
+        keeping in mind that the
+        :class:`_engine.Engine`
+        can still be used for new requests in which case
+        it re-acquires connection resources.
+
+        .. versionadded:: 1.0.5
+
+        """
+
+    def begin(self, conn):
+        """Intercept begin() events.
+
+        :param conn: :class:`_engine.Connection` object
+
+        """
+
+    def rollback(self, conn):
+        """Intercept rollback() events, as initiated by a
+        :class:`.Transaction`.
+
+        Note that the :class:`_pool.Pool` also "auto-rolls back"
+        a DBAPI connection upon checkin, if the ``reset_on_return``
+        flag is set to its default value of ``'rollback'``.
+        To intercept this
+        rollback, use the :meth:`_events.PoolEvents.reset` hook.
+
+        :param conn: :class:`_engine.Connection` object
+
+        .. seealso::
+
+            :meth:`_events.PoolEvents.reset`
+
+        """
+
+    def commit(self, conn):
+        """Intercept commit() events, as initiated by a
+        :class:`.Transaction`.
+
+        Note that the :class:`_pool.Pool` may also "auto-commit"
+        a DBAPI connection upon checkin, if the ``reset_on_return``
+        flag is set to the value ``'commit'``.  To intercept this
+        commit, use the :meth:`_events.PoolEvents.reset` hook.
+
+        :param conn: :class:`_engine.Connection` object
+        """
+
+    def savepoint(self, conn, name):
+        """Intercept savepoint() events.
+
+        :param conn: :class:`_engine.Connection` object
+        :param name: specified name used for the savepoint.
+
+        """
+
+    def rollback_savepoint(self, conn, name, context):
+        """Intercept rollback_savepoint() events.
+
+        :param conn: :class:`_engine.Connection` object
+        :param name: specified name used for the savepoint.
+        :param context: not used
+
+        """
+        # TODO: deprecate "context"
+
+    def release_savepoint(self, conn, name, context):
+        """Intercept release_savepoint() events.
+
+        :param conn: :class:`_engine.Connection` object
+        :param name: specified name used for the savepoint.
+        :param context: not used
+
+        """
+        # TODO: deprecate "context"
+
+    def begin_twophase(self, conn, xid):
+        """Intercept begin_twophase() events.
+
+        :param conn: :class:`_engine.Connection` object
+        :param xid: two-phase XID identifier
+
+        """
+
+    def prepare_twophase(self, conn, xid):
+        """Intercept prepare_twophase() events.
+
+        :param conn: :class:`_engine.Connection` object
+        :param xid: two-phase XID identifier
+        """
+
+    def rollback_twophase(self, conn, xid, is_prepared):
+        """Intercept rollback_twophase() events.
+
+        :param conn: :class:`_engine.Connection` object
+        :param xid: two-phase XID identifier
+        :param is_prepared: boolean, indicates if
+         :meth:`.TwoPhaseTransaction.prepare` was called.
+
+        """
+
+    def commit_twophase(self, conn, xid, is_prepared):
+        """Intercept commit_twophase() events.
+
+        :param conn: :class:`_engine.Connection` object
+        :param xid: two-phase XID identifier
+        :param is_prepared: boolean, indicates if
+         :meth:`.TwoPhaseTransaction.prepare` was called.
+
+        """
+
+
+class DialectEvents(event.Events):
+    """event interface for execution-replacement functions.
+
+    These events allow direct instrumentation and replacement
+    of key dialect functions which interact with the DBAPI.
+
+    .. note::
+
+        :class:`.DialectEvents` hooks should be considered **semi-public**
+        and experimental.
+        These hooks are not for general use and are only for those situations
+        where intricate re-statement of DBAPI mechanics must be injected onto
+        an existing dialect.  For general-use statement-interception events,
+        please use the :class:`_events.ConnectionEvents` interface.
+
+    .. seealso::
+
+        :meth:`_events.ConnectionEvents.before_cursor_execute`
+
+        :meth:`_events.ConnectionEvents.before_execute`
+
+        :meth:`_events.ConnectionEvents.after_cursor_execute`
+
+        :meth:`_events.ConnectionEvents.after_execute`
+
+
+    .. versionadded:: 0.9.4
+
+    """
+
+    _target_class_doc = "SomeEngine"
+    _dispatch_target = Dialect
+
+    @classmethod
+    def _listen(cls, event_key, retval=False):
+        target = event_key.dispatch_target
+
+        target._has_events = True
+        event_key.base_listen()
+
+    @classmethod
+    def _accept_with(cls, target):
+        if isinstance(target, type):
+            if issubclass(target, Engine):
+                return Dialect
+            elif issubclass(target, Dialect):
+                return target
+        elif isinstance(target, Engine):
+            return target.dialect
+        elif isinstance(target, Dialect):
+            return target
+        elif hasattr(target, "dispatch") and hasattr(
+            target.dispatch._events, "_no_async_engine_events"
+        ):
+            target.dispatch._events._no_async_engine_events()
+        else:
+            return None
+
+    def do_connect(self, dialect, conn_rec, cargs, cparams):
+        """Receive connection arguments before a connection is made.
+
+        This event is useful in that it allows the handler to manipulate the
+        cargs and/or cparams collections that control how the DBAPI
+        ``connect()`` function will be called. ``cargs`` will always be a
+        Python list that can be mutated in-place, and ``cparams`` a Python
+        dictionary that may also be mutated::
+
+            e = create_engine("postgresql+psycopg2://user@host/dbname")
+
+            @event.listens_for(e, 'do_connect')
+            def receive_do_connect(dialect, conn_rec, cargs, cparams):
+                cparams["password"] = "some_password"
+
+        The event hook may also be used to override the call to ``connect()``
+        entirely, by returning a non-``None`` DBAPI connection object::
+
+            e = create_engine("postgresql+psycopg2://user@host/dbname")
+
+            @event.listens_for(e, 'do_connect')
+            def receive_do_connect(dialect, conn_rec, cargs, cparams):
+                return psycopg2.connect(*cargs, **cparams)
+
+
+        .. versionadded:: 1.0.3
+
+        .. seealso::
+
+            :ref:`custom_dbapi_args`
+
+        """
+
+    def do_executemany(self, cursor, statement, parameters, context):
+        """Receive a cursor to have executemany() called.
+
+        Return the value True to halt further events from invoking,
+        and to indicate that the cursor execution has already taken
+        place within the event handler.
+
+        """
+
+    def do_execute_no_params(self, cursor, statement, context):
+        """Receive a cursor to have execute() with no parameters called.
+
+        Return the value True to halt further events from invoking,
+        and to indicate that the cursor execution has already taken
+        place within the event handler.
+
+        """
+
+    def do_execute(self, cursor, statement, parameters, context):
+        """Receive a cursor to have execute() called.
+
+        Return the value True to halt further events from invoking,
+        and to indicate that the cursor execution has already taken
+        place within the event handler.
+
+        """
+
+    def do_setinputsizes(
+        self, inputsizes, cursor, statement, parameters, context
+    ):
+        """Receive the setinputsizes dictionary for possible modification.
+
+        This event is emitted in the case where the dialect makes use of the
+        DBAPI ``cursor.setinputsizes()`` method which passes information about
+        parameter binding for a particular statement.   The given
+        ``inputsizes`` dictionary will contain :class:`.BindParameter` objects
+        as keys, linked to DBAPI-specific type objects as values; for
+        parameters that are not bound, they are added to the dictionary with
+        ``None`` as the value, which means the parameter will not be included
+        in the ultimate setinputsizes call.   The event may be used to inspect
+        and/or log the datatypes that are being bound, as well as to modify the
+        dictionary in place.  Parameters can be added, modified, or removed
+        from this dictionary.   Callers will typically want to inspect the
+        :attr:`.BindParameter.type` attribute of the given bind objects in
+        order to make decisions about the DBAPI object.
+
+        After the event, the ``inputsizes`` dictionary is converted into
+        an appropriate datastructure to be passed to ``cursor.setinputsizes``;
+        either a list for a positional bound parameter execution style,
+        or a dictionary of string parameter keys to DBAPI type objects for
+        a named bound parameter execution style.
+
+        The setinputsizes hook overall is only used for dialects which include
+        the flag ``use_setinputsizes=True``.  Dialects which use this
+        include cx_Oracle, pg8000, asyncpg, and pyodbc dialects.
+
+        .. note::
+
+            For use with pyodbc, the ``use_setinputsizes`` flag
+            must be passed to the dialect, e.g.::
+
+                create_engine("mssql+pyodbc://...", use_setinputsizes=True)
+
+            .. seealso::
+
+                  :ref:`mssql_pyodbc_setinputsizes`
+
+        .. versionadded:: 1.2.9
+
+        .. seealso::
+
+            :ref:`cx_oracle_setinputsizes`
+
+        """
+        pass

lib/sqlalchemy/engine/mock.py

@@ -0,0 +1,118 @@
+# engine/mock.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from operator import attrgetter
+
+from . import base
+from . import url as _url
+from .. import util
+from ..sql import ddl
+
+
+class MockConnection(base.Connectable):
+    def __init__(self, dialect, execute):
+        self._dialect = dialect
+        self.execute = execute
+
+    engine = property(lambda s: s)
+    dialect = property(attrgetter("_dialect"))
+    name = property(lambda s: s._dialect.name)
+
+    def schema_for_object(self, obj):
+        return obj.schema
+
+    def connect(self, **kwargs):
+        return self
+
+    def execution_options(self, **kw):
+        return self
+
+    def compiler(self, statement, parameters, **kwargs):
+        return self._dialect.compiler(
+            statement, parameters, engine=self, **kwargs
+        )
+
+    def create(self, entity, **kwargs):
+        kwargs["checkfirst"] = False
+
+        ddl.SchemaGenerator(self.dialect, self, **kwargs).traverse_single(
+            entity
+        )
+
+    def drop(self, entity, **kwargs):
+        kwargs["checkfirst"] = False
+
+        ddl.SchemaDropper(self.dialect, self, **kwargs).traverse_single(entity)
+
+    def _run_ddl_visitor(
+        self, visitorcallable, element, connection=None, **kwargs
+    ):
+        kwargs["checkfirst"] = False
+        visitorcallable(self.dialect, self, **kwargs).traverse_single(element)
+
+    def execute(self, object_, *multiparams, **params):
+        raise NotImplementedError()
+
+
+def create_mock_engine(url, executor, **kw):
+    """Create a "mock" engine used for echoing DDL.
+
+    This is a utility function used for debugging or storing the output of DDL
+    sequences as generated by :meth:`_schema.MetaData.create_all`
+    and related methods.
+
+    The function accepts a URL which is used only to determine the kind of
+    dialect to be used, as well as an "executor" callable function which
+    will receive a SQL expression object and parameters, which can then be
+    echoed or otherwise printed.   The executor's return value is not handled,
+    nor does the engine allow regular string statements to be invoked, and
+    is therefore only useful for DDL that is sent to the database without
+    receiving any results.
+
+    E.g.::
+
+        from sqlalchemy import create_mock_engine
+
+        def dump(sql, *multiparams, **params):
+            print(sql.compile(dialect=engine.dialect))
+
+        engine = create_mock_engine('postgresql://', dump)
+        metadata.create_all(engine, checkfirst=False)
+
+    :param url: A string URL which typically needs to contain only the
+     database backend name.
+
+    :param executor: a callable which receives the arguments ``sql``,
+     ``*multiparams`` and ``**params``.  The ``sql`` parameter is typically
+     an instance of :class:`.DDLElement`, which can then be compiled into a
+     string using :meth:`.DDLElement.compile`.
+
+    .. versionadded:: 1.4 - the :func:`.create_mock_engine` function replaces
+       the previous "mock" engine strategy used with
+       :func:`_sa.create_engine`.
+
+    .. seealso::
+
+        :ref:`faq_ddl_as_string`
+
+    """
+
+    # create url.URL object
+    u = _url.make_url(url)
+
+    dialect_cls = u.get_dialect()
+
+    dialect_args = {}
+    # consume dialect arguments from kwargs
+    for k in util.get_cls_kwargs(dialect_cls):
+        if k in kw:
+            dialect_args[k] = kw.pop(k)
+
+    # create dialect
+    dialect = dialect_cls(**dialect_args)
+
+    return MockConnection(dialect, executor)

lib/sqlalchemy/engine/row.py

@@ -0,0 +1,621 @@
+# engine/row.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""Define row constructs including :class:`.Row`."""
+
+
+import operator
+
+from .. import util
+from ..sql import util as sql_util
+from ..util.compat import collections_abc
+
+MD_INDEX = 0  # integer index in cursor.description
+
+# This reconstructor is necessary so that pickles with the C extension or
+# without use the same Binary format.
+try:
+    # We need a different reconstructor on the C extension so that we can
+    # add extra checks that fields have correctly been initialized by
+    # __setstate__.
+    from sqlalchemy.cresultproxy import safe_rowproxy_reconstructor
+
+    # The extra function embedding is needed so that the
+    # reconstructor function has the same signature whether or not
+    # the extension is present.
+    def rowproxy_reconstructor(cls, state):
+        return safe_rowproxy_reconstructor(cls, state)
+
+
+except ImportError:
+
+    def rowproxy_reconstructor(cls, state):
+        obj = cls.__new__(cls)
+        obj.__setstate__(state)
+        return obj
+
+
+KEY_INTEGER_ONLY = 0
+"""__getitem__ only allows integer values, raises TypeError otherwise"""
+
+KEY_OBJECTS_ONLY = 1
+"""__getitem__ only allows string/object values, raises TypeError otherwise"""
+
+KEY_OBJECTS_BUT_WARN = 2
+"""__getitem__ allows integer or string/object values, but emits a 2.0
+deprecation warning if string/object is passed"""
+
+KEY_OBJECTS_NO_WARN = 3
+"""__getitem__ allows integer or string/object values with no warnings
+or errors."""
+
+try:
+    from sqlalchemy.cresultproxy import BaseRow
+
+    _baserow_usecext = True
+except ImportError:
+    _baserow_usecext = False
+
+    class BaseRow(object):
+        __slots__ = ("_parent", "_data", "_keymap", "_key_style")
+
+        def __init__(self, parent, processors, keymap, key_style, data):
+            """Row objects are constructed by CursorResult objects."""
+
+            object.__setattr__(self, "_parent", parent)
+
+            if processors:
+                object.__setattr__(
+                    self,
+                    "_data",
+                    tuple(
+                        [
+                            proc(value) if proc else value
+                            for proc, value in zip(processors, data)
+                        ]
+                    ),
+                )
+            else:
+                object.__setattr__(self, "_data", tuple(data))
+
+            object.__setattr__(self, "_keymap", keymap)
+
+            object.__setattr__(self, "_key_style", key_style)
+
+        def __reduce__(self):
+            return (
+                rowproxy_reconstructor,
+                (self.__class__, self.__getstate__()),
+            )
+
+        def _filter_on_values(self, filters):
+            return Row(
+                self._parent,
+                filters,
+                self._keymap,
+                self._key_style,
+                self._data,
+            )
+
+        def _values_impl(self):
+            return list(self)
+
+        def __iter__(self):
+            return iter(self._data)
+
+        def __len__(self):
+            return len(self._data)
+
+        def __hash__(self):
+            return hash(self._data)
+
+        def _get_by_int_impl(self, key):
+            return self._data[key]
+
+        def _get_by_key_impl(self, key):
+            if int in key.__class__.__mro__:
+                return self._data[key]
+
+            if self._key_style == KEY_INTEGER_ONLY:
+                self._parent._raise_for_nonint(key)
+
+            # the following is all LegacyRow support.   none of this
+            # should be called if not LegacyRow
+            # assert isinstance(self, LegacyRow)
+
+            try:
+                rec = self._keymap[key]
+            except KeyError as ke:
+                rec = self._parent._key_fallback(key, ke)
+            except TypeError:
+                if isinstance(key, slice):
+                    return tuple(self._data[key])
+                else:
+                    raise
+
+            mdindex = rec[MD_INDEX]
+            if mdindex is None:
+                self._parent._raise_for_ambiguous_column_name(rec)
+
+            elif self._key_style == KEY_OBJECTS_BUT_WARN and mdindex != key:
+                self._parent._warn_for_nonint(key)
+
+            return self._data[mdindex]
+
+        # The original 1.4 plan was that Row would not allow row["str"]
+        # access, however as the C extensions were inadvertently allowing
+        # this coupled with the fact that orm Session sets future=True,
+        # this allows a softer upgrade path.  see #6218
+        __getitem__ = _get_by_key_impl
+
+        def _get_by_key_impl_mapping(self, key):
+            try:
+                rec = self._keymap[key]
+            except KeyError as ke:
+                rec = self._parent._key_fallback(key, ke)
+
+            mdindex = rec[MD_INDEX]
+            if mdindex is None:
+                self._parent._raise_for_ambiguous_column_name(rec)
+            elif (
+                self._key_style == KEY_OBJECTS_ONLY
+                and int in key.__class__.__mro__
+            ):
+                raise KeyError(key)
+
+            return self._data[mdindex]
+
+        def __getattr__(self, name):
+            try:
+                return self._get_by_key_impl_mapping(name)
+            except KeyError as e:
+                util.raise_(AttributeError(e.args[0]), replace_context=e)
+
+
+class Row(BaseRow, collections_abc.Sequence):
+    """Represent a single result row.
+
+    The :class:`.Row` object represents a row of a database result.  It is
+    typically associated in the 1.x series of SQLAlchemy with the
+    :class:`_engine.CursorResult` object, however is also used by the ORM for
+    tuple-like results as of SQLAlchemy 1.4.
+
+    The :class:`.Row` object seeks to act as much like a Python named
+    tuple as possible.   For mapping (i.e. dictionary) behavior on a row,
+    such as testing for containment of keys, refer to the :attr:`.Row._mapping`
+    attribute.
+
+    .. seealso::
+
+        :ref:`tutorial_selecting_data` - includes examples of selecting
+        rows from SELECT statements.
+
+        :class:`.LegacyRow` - Compatibility interface introduced in SQLAlchemy
+        1.4.
+
+    .. versionchanged:: 1.4
+
+        Renamed ``RowProxy`` to :class:`.Row`.  :class:`.Row` is no longer a
+        "proxy" object in that it contains the final form of data within it,
+        and now acts mostly like a named tuple.  Mapping-like functionality is
+        moved to the :attr:`.Row._mapping` attribute, but will remain available
+        in SQLAlchemy 1.x series via the :class:`.LegacyRow` class that is used
+        by :class:`_engine.LegacyCursorResult`.
+        See :ref:`change_4710_core` for background
+        on this change.
+
+    """
+
+    __slots__ = ()
+
+    # in 2.0, this should be KEY_INTEGER_ONLY
+    _default_key_style = KEY_OBJECTS_BUT_WARN
+
+    def __setattr__(self, name, value):
+        raise AttributeError("can't set attribute")
+
+    def __delattr__(self, name):
+        raise AttributeError("can't delete attribute")
+
+    @property
+    def _mapping(self):
+        """Return a :class:`.RowMapping` for this :class:`.Row`.
+
+        This object provides a consistent Python mapping (i.e. dictionary)
+        interface for the data contained within the row.   The :class:`.Row`
+        by itself behaves like a named tuple, however in the 1.4 series of
+        SQLAlchemy, the :class:`.LegacyRow` class is still used by Core which
+        continues to have mapping-like behaviors against the row object
+        itself.
+
+        .. seealso::
+
+            :attr:`.Row._fields`
+
+        .. versionadded:: 1.4
+
+        """
+        return RowMapping(
+            self._parent,
+            None,
+            self._keymap,
+            RowMapping._default_key_style,
+            self._data,
+        )
+
+    def _special_name_accessor(name):
+        """Handle ambiguous names such as "count" and "index" """
+
+        @property
+        def go(self):
+            if self._parent._has_key(name):
+                return self.__getattr__(name)
+            else:
+
+                def meth(*arg, **kw):
+                    return getattr(collections_abc.Sequence, name)(
+                        self, *arg, **kw
+                    )
+
+                return meth
+
+        return go
+
+    count = _special_name_accessor("count")
+    index = _special_name_accessor("index")
+
+    def __contains__(self, key):
+        return key in self._data
+
+    def __getstate__(self):
+        return {
+            "_parent": self._parent,
+            "_data": self._data,
+            "_key_style": self._key_style,
+        }
+
+    def __setstate__(self, state):
+        parent = state["_parent"]
+        object.__setattr__(self, "_parent", parent)
+        object.__setattr__(self, "_data", state["_data"])
+        object.__setattr__(self, "_keymap", parent._keymap)
+        object.__setattr__(self, "_key_style", state["_key_style"])
+
+    def _op(self, other, op):
+        return (
+            op(tuple(self), tuple(other))
+            if isinstance(other, Row)
+            else op(tuple(self), other)
+        )
+
+    __hash__ = BaseRow.__hash__
+
+    def __lt__(self, other):
+        return self._op(other, operator.lt)
+
+    def __le__(self, other):
+        return self._op(other, operator.le)
+
+    def __ge__(self, other):
+        return self._op(other, operator.ge)
+
+    def __gt__(self, other):
+        return self._op(other, operator.gt)
+
+    def __eq__(self, other):
+        return self._op(other, operator.eq)
+
+    def __ne__(self, other):
+        return self._op(other, operator.ne)
+
+    def __repr__(self):
+        return repr(sql_util._repr_row(self))
+
+    @util.deprecated_20(
+        ":meth:`.Row.keys`",
+        alternative="Use the namedtuple standard accessor "
+        ":attr:`.Row._fields`, or for full mapping behavior use  "
+        "row._mapping.keys() ",
+    )
+    def keys(self):
+        """Return the list of keys as strings represented by this
+        :class:`.Row`.
+
+        The keys can represent the labels of the columns returned by a core
+        statement or the names of the orm classes returned by an orm
+        execution.
+
+        This method is analogous to the Python dictionary ``.keys()`` method,
+        except that it returns a list, not an iterator.
+
+        .. seealso::
+
+            :attr:`.Row._fields`
+
+            :attr:`.Row._mapping`
+
+        """
+        return self._parent.keys
+
+    @property
+    def _fields(self):
+        """Return a tuple of string keys as represented by this
+        :class:`.Row`.
+
+        The keys can represent the labels of the columns returned by a core
+        statement or the names of the orm classes returned by an orm
+        execution.
+
+        This attribute is analogous to the Python named tuple ``._fields``
+        attribute.
+
+        .. versionadded:: 1.4
+
+        .. seealso::
+
+            :attr:`.Row._mapping`
+
+        """
+        return tuple([k for k in self._parent.keys if k is not None])
+
+    def _asdict(self):
+        """Return a new dict which maps field names to their corresponding
+        values.
+
+        This method is analogous to the Python named tuple ``._asdict()``
+        method, and works by applying the ``dict()`` constructor to the
+        :attr:`.Row._mapping` attribute.
+
+        .. versionadded:: 1.4
+
+        .. seealso::
+
+            :attr:`.Row._mapping`
+
+        """
+        return dict(self._mapping)
+
+    def _replace(self):
+        raise NotImplementedError()
+
+    @property
+    def _field_defaults(self):
+        raise NotImplementedError()
+
+
+class LegacyRow(Row):
+    """A subclass of :class:`.Row` that delivers 1.x SQLAlchemy behaviors
+    for Core.
+
+    The :class:`.LegacyRow` class is where most of the Python mapping
+    (i.e. dictionary-like)
+    behaviors are implemented for the row object.  The mapping behavior
+    of :class:`.Row` going forward is accessible via the :class:`.Row._mapping`
+    attribute.
+
+    .. versionadded:: 1.4 - added :class:`.LegacyRow` which encapsulates most
+       of the deprecated behaviors of :class:`.Row`.
+
+    """
+
+    __slots__ = ()
+
+    if util.SQLALCHEMY_WARN_20:
+        _default_key_style = KEY_OBJECTS_BUT_WARN
+    else:
+        _default_key_style = KEY_OBJECTS_NO_WARN
+
+    def __contains__(self, key):
+        return self._parent._contains(key, self)
+
+    # prior to #6218, LegacyRow would redirect the behavior of __getitem__
+    # for the non C version of BaseRow. This is now set up by Python BaseRow
+    # in all cases
+    # if not _baserow_usecext:
+    #    __getitem__ = BaseRow._get_by_key_impl
+
+    @util.deprecated(
+        "1.4",
+        "The :meth:`.LegacyRow.has_key` method is deprecated and will be "
+        "removed in a future release.  To test for key membership, use "
+        "the :attr:`Row._mapping` attribute, i.e. 'key in row._mapping`.",
+    )
+    def has_key(self, key):
+        """Return True if this :class:`.LegacyRow` contains the given key.
+
+        Through the SQLAlchemy 1.x series, the ``__contains__()`` method of
+        :class:`.Row` (or :class:`.LegacyRow` as of SQLAlchemy 1.4)  also links
+        to :meth:`.Row.has_key`, in that an expression such as ::
+
+            "some_col" in row
+
+        Will return True if the row contains a column named ``"some_col"``,
+        in the way that a Python mapping works.
+
+        However, it is planned that the 2.0 series of SQLAlchemy will reverse
+        this behavior so that ``__contains__()`` will refer to a value being
+        present in the row, in the way that a Python tuple works.
+
+        .. seealso::
+
+            :ref:`change_4710_core`
+
+        """
+
+        return self._parent._has_key(key)
+
+    @util.deprecated(
+        "1.4",
+        "The :meth:`.LegacyRow.items` method is deprecated and will be "
+        "removed in a future release.  Use the :attr:`Row._mapping` "
+        "attribute, i.e., 'row._mapping.items()'.",
+    )
+    def items(self):
+        """Return a list of tuples, each tuple containing a key/value pair.
+
+        This method is analogous to the Python dictionary ``.items()`` method,
+        except that it returns a list, not an iterator.
+
+        """
+
+        return [(key, self[key]) for key in self.keys()]
+
+    @util.deprecated(
+        "1.4",
+        "The :meth:`.LegacyRow.iterkeys` method is deprecated and will be "
+        "removed in a future release.  Use the :attr:`Row._mapping` "
+        "attribute, i.e., 'row._mapping.keys()'.",
+    )
+    def iterkeys(self):
+        """Return a an iterator against the :meth:`.Row.keys` method.
+
+        This method is analogous to the Python-2-only dictionary
+        ``.iterkeys()`` method.
+
+        """
+        return iter(self._parent.keys)
+
+    @util.deprecated(
+        "1.4",
+        "The :meth:`.LegacyRow.itervalues` method is deprecated and will be "
+        "removed in a future release.  Use the :attr:`Row._mapping` "
+        "attribute, i.e., 'row._mapping.values()'.",
+    )
+    def itervalues(self):
+        """Return a an iterator against the :meth:`.Row.values` method.
+
+        This method is analogous to the Python-2-only dictionary
+        ``.itervalues()`` method.
+
+        """
+        return iter(self)
+
+    @util.deprecated(
+        "1.4",
+        "The :meth:`.LegacyRow.values` method is deprecated and will be "
+        "removed in a future release.  Use the :attr:`Row._mapping` "
+        "attribute, i.e., 'row._mapping.values()'.",
+    )
+    def values(self):
+        """Return the values represented by this :class:`.Row` as a list.
+
+        This method is analogous to the Python dictionary ``.values()`` method,
+        except that it returns a list, not an iterator.
+
+        """
+
+        return self._values_impl()
+
+
+BaseRowProxy = BaseRow
+RowProxy = Row
+
+
+class ROMappingView(
+    collections_abc.KeysView,
+    collections_abc.ValuesView,
+    collections_abc.ItemsView,
+):
+    __slots__ = (
+        "_mapping",
+        "_items",
+    )
+
+    def __init__(self, mapping, items):
+        self._mapping = mapping
+        self._items = items
+
+    def __len__(self):
+        return len(self._items)
+
+    def __repr__(self):
+        return "{0.__class__.__name__}({0._mapping!r})".format(self)
+
+    def __iter__(self):
+        return iter(self._items)
+
+    def __contains__(self, item):
+        return item in self._items
+
+    def __eq__(self, other):
+        return list(other) == list(self)
+
+    def __ne__(self, other):
+        return list(other) != list(self)
+
+
+class RowMapping(BaseRow, collections_abc.Mapping):
+    """A ``Mapping`` that maps column names and objects to :class:`.Row`
+    values.
+
+    The :class:`.RowMapping` is available from a :class:`.Row` via the
+    :attr:`.Row._mapping` attribute, as well as from the iterable interface
+    provided by the :class:`.MappingResult` object returned by the
+    :meth:`_engine.Result.mappings` method.
+
+    :class:`.RowMapping` supplies Python mapping (i.e. dictionary) access to
+    the  contents of the row.   This includes support for testing of
+    containment of specific keys (string column names or objects), as well
+    as iteration of keys, values, and items::
+
+        for row in result:
+            if 'a' in row._mapping:
+                print("Column 'a': %s" % row._mapping['a'])
+
+            print("Column b: %s" % row._mapping[table.c.b])
+
+
+    .. versionadded:: 1.4 The :class:`.RowMapping` object replaces the
+       mapping-like access previously provided by a database result row,
+       which now seeks to behave mostly like a named tuple.
+
+    """
+
+    __slots__ = ()
+
+    _default_key_style = KEY_OBJECTS_ONLY
+
+    if not _baserow_usecext:
+
+        __getitem__ = BaseRow._get_by_key_impl_mapping
+
+        def _values_impl(self):
+            return list(self._data)
+
+    def __iter__(self):
+        return (k for k in self._parent.keys if k is not None)
+
+    def __len__(self):
+        return len(self._data)
+
+    def __contains__(self, key):
+        return self._parent._has_key(key)
+
+    def __repr__(self):
+        return repr(dict(self))
+
+    def items(self):
+        """Return a view of key/value tuples for the elements in the
+        underlying :class:`.Row`.
+
+        """
+        return ROMappingView(self, [(key, self[key]) for key in self.keys()])
+
+    def keys(self):
+        """Return a view of 'keys' for string column names represented
+        by the underlying :class:`.Row`.
+
+        """
+
+        return self._parent.keys
+
+    def values(self):
+        """Return a view of values for the values represented in the
+        underlying :class:`.Row`.
+
+        """
+        return ROMappingView(self, self._values_impl())

lib/sqlalchemy/engine/strategies.py

@@ -0,0 +1,17 @@
+# engine/strategies.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""Deprecated mock engine strategy used by Alembic.
+
+
+"""
+
+from .mock import MockConnection  # noqa
+
+
+class MockEngineStrategy(object):
+    MockConnection = MockConnection

lib/sqlalchemy/engine/url.py

@@ -0,0 +1,806 @@
+# engine/url.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""Provides the :class:`~sqlalchemy.engine.url.URL` class which encapsulates
+information about a database connection specification.
+
+The URL object is created automatically when
+:func:`~sqlalchemy.engine.create_engine` is called with a string
+argument; alternatively, the URL is a public-facing construct which can
+be used directly and is also accepted directly by ``create_engine()``.
+"""
+
+import re
+
+from .interfaces import Dialect
+from .. import exc
+from .. import util
+from ..dialects import plugins
+from ..dialects import registry
+from ..util import collections_abc
+from ..util import compat
+
+
+class URL(
+    util.namedtuple(
+        "URL",
+        [
+            "drivername",
+            "username",
+            "password",
+            "host",
+            "port",
+            "database",
+            "query",
+        ],
+    )
+):
+    """
+    Represent the components of a URL used to connect to a database.
+
+    This object is suitable to be passed directly to a
+    :func:`_sa.create_engine` call.  The fields of the URL are parsed
+    from a string by the :func:`.make_url` function.  The string
+    format of the URL is an RFC-1738-style string.
+
+    To create a new :class:`_engine.URL` object, use the
+    :func:`_engine.url.make_url` function.  To construct a :class:`_engine.URL`
+    programmatically, use the :meth:`_engine.URL.create` constructor.
+
+    .. versionchanged:: 1.4
+
+        The :class:`_engine.URL` object is now an immutable object.  To
+        create a URL, use the :func:`_engine.make_url` or
+        :meth:`_engine.URL.create` function / method.  To modify
+        a :class:`_engine.URL`, use methods like
+        :meth:`_engine.URL.set` and
+        :meth:`_engine.URL.update_query_dict` to return a new
+        :class:`_engine.URL` object with modifications.   See notes for this
+        change at :ref:`change_5526`.
+
+    :class:`_engine.URL` contains the following attributes:
+
+    * :attr:`_engine.URL.drivername`: database backend and driver name, such as
+      ``postgresql+psycopg2``
+    * :attr:`_engine.URL.username`: username string
+    * :attr:`_engine.URL.password`: password string
+    * :attr:`_engine.URL.host`: string hostname
+    * :attr:`_engine.URL.port`: integer port number
+    * :attr:`_engine.URL.database`: string database name
+    * :attr:`_engine.URL.query`: an immutable mapping representing the query
+      string.  contains strings for keys and either strings or tuples of
+      strings for values.
+
+
+    """
+
+    def __new__(self, *arg, **kw):
+        if kw.pop("_new_ok", False):
+            return super(URL, self).__new__(self, *arg, **kw)
+        else:
+            util.warn_deprecated(
+                "Calling URL() directly is deprecated and will be disabled "
+                "in a future release.  The public constructor for URL is "
+                "now the URL.create() method.",
+                "1.4",
+            )
+            return URL.create(*arg, **kw)
+
+    @classmethod
+    def create(
+        cls,
+        drivername,
+        username=None,
+        password=None,
+        host=None,
+        port=None,
+        database=None,
+        query=util.EMPTY_DICT,
+    ):
+        """Create a new :class:`_engine.URL` object.
+
+        :param drivername: the name of the database backend. This name will
+          correspond to a module in sqlalchemy/databases or a third party
+          plug-in.
+        :param username: The user name.
+        :param password: database password.  Is typically a string, but may
+          also be an object that can be stringified with ``str()``.
+
+          .. note::  A password-producing object will be stringified only
+             **once** per :class:`_engine.Engine` object.  For dynamic password
+             generation per connect, see :ref:`engines_dynamic_tokens`.
+
+        :param host: The name of the host.
+        :param port: The port number.
+        :param database: The database name.
+        :param query: A dictionary of string keys to string values to be passed
+          to the dialect and/or the DBAPI upon connect.   To specify non-string
+          parameters to a Python DBAPI directly, use the
+          :paramref:`_sa.create_engine.connect_args` parameter to
+          :func:`_sa.create_engine`.   See also
+          :attr:`_engine.URL.normalized_query` for a dictionary that is
+          consistently string->list of string.
+        :return: new :class:`_engine.URL` object.
+
+        .. versionadded:: 1.4
+
+            The :class:`_engine.URL` object is now an **immutable named
+            tuple**.  In addition, the ``query`` dictionary is also immutable.
+            To create a URL, use the :func:`_engine.url.make_url` or
+            :meth:`_engine.URL.create` function/ method.  To modify a
+            :class:`_engine.URL`, use the :meth:`_engine.URL.set` and
+            :meth:`_engine.URL.update_query` methods.
+
+        """
+
+        return cls(
+            cls._assert_str(drivername, "drivername"),
+            cls._assert_none_str(username, "username"),
+            password,
+            cls._assert_none_str(host, "host"),
+            cls._assert_port(port),
+            cls._assert_none_str(database, "database"),
+            cls._str_dict(query),
+            _new_ok=True,
+        )
+
+    @classmethod
+    def _assert_port(cls, port):
+        if port is None:
+            return None
+        try:
+            return int(port)
+        except TypeError:
+            raise TypeError("Port argument must be an integer or None")
+
+    @classmethod
+    def _assert_str(cls, v, paramname):
+        if not isinstance(v, compat.string_types):
+            raise TypeError("%s must be a string" % paramname)
+        return v
+
+    @classmethod
+    def _assert_none_str(cls, v, paramname):
+        if v is None:
+            return v
+
+        return cls._assert_str(v, paramname)
+
+    @classmethod
+    def _str_dict(cls, dict_):
+        if dict_ is None:
+            return util.EMPTY_DICT
+
+        def _assert_value(val):
+            if isinstance(val, compat.string_types):
+                return val
+            elif isinstance(val, collections_abc.Sequence):
+                return tuple(_assert_value(elem) for elem in val)
+            else:
+                raise TypeError(
+                    "Query dictionary values must be strings or "
+                    "sequences of strings"
+                )
+
+        def _assert_str(v):
+            if not isinstance(v, compat.string_types):
+                raise TypeError("Query dictionary keys must be strings")
+            return v
+
+        if isinstance(dict_, collections_abc.Sequence):
+            dict_items = dict_
+        else:
+            dict_items = dict_.items()
+
+        return util.immutabledict(
+            {
+                _assert_str(key): _assert_value(
+                    value,
+                )
+                for key, value in dict_items
+            }
+        )
+
+    def set(
+        self,
+        drivername=None,
+        username=None,
+        password=None,
+        host=None,
+        port=None,
+        database=None,
+        query=None,
+    ):
+        """return a new :class:`_engine.URL` object with modifications.
+
+        Values are used if they are non-None.  To set a value to ``None``
+        explicitly, use the :meth:`_engine.URL._replace` method adapted
+        from ``namedtuple``.
+
+        :param drivername: new drivername
+        :param username: new username
+        :param password: new password
+        :param host: new hostname
+        :param port: new port
+        :param query: new query parameters, passed a dict of string keys
+         referring to string or sequence of string values.  Fully
+         replaces the previous list of arguments.
+
+        :return: new :class:`_engine.URL` object.
+
+        .. versionadded:: 1.4
+
+        .. seealso::
+
+            :meth:`_engine.URL.update_query_dict`
+
+        """
+
+        kw = {}
+        if drivername is not None:
+            kw["drivername"] = drivername
+        if username is not None:
+            kw["username"] = username
+        if password is not None:
+            kw["password"] = password
+        if host is not None:
+            kw["host"] = host
+        if port is not None:
+            kw["port"] = port
+        if database is not None:
+            kw["database"] = database
+        if query is not None:
+            kw["query"] = query
+
+        return self._replace(**kw)
+
+    def _replace(self, **kw):
+        """Override ``namedtuple._replace()`` to provide argument checking."""
+
+        if "drivername" in kw:
+            self._assert_str(kw["drivername"], "drivername")
+        for name in "username", "host", "database":
+            if name in kw:
+                self._assert_none_str(kw[name], name)
+        if "port" in kw:
+            self._assert_port(kw["port"])
+        if "query" in kw:
+            kw["query"] = self._str_dict(kw["query"])
+
+        return super(URL, self)._replace(**kw)
+
+    def update_query_string(self, query_string, append=False):
+        """Return a new :class:`_engine.URL` object with the :attr:`_engine.URL.query`
+        parameter dictionary updated by the given query string.
+
+        E.g.::
+
+            >>> from sqlalchemy.engine import make_url
+            >>> url = make_url("postgresql://user:pass@host/dbname")
+            >>> url = url.update_query_string("alt_host=host1&alt_host=host2&ssl_cipher=%2Fpath%2Fto%2Fcrt")
+            >>> str(url)
+            'postgresql://user:pass@host/dbname?alt_host=host1&alt_host=host2&ssl_cipher=%2Fpath%2Fto%2Fcrt'
+
+        :param query_string: a URL escaped query string, not including the
+         question mark.
+
+        :param append: if True, parameters in the existing query string will
+         not be removed; new parameters will be in addition to those present.
+         If left at its default of False, keys present in the given query
+         parameters will replace those of the existing query string.
+
+        .. versionadded:: 1.4
+
+        .. seealso::
+
+            :attr:`_engine.URL.query`
+
+            :meth:`_engine.URL.update_query_dict`
+
+        """  # noqa: E501
+        return self.update_query_pairs(
+            util.parse_qsl(query_string), append=append
+        )
+
+    def update_query_pairs(self, key_value_pairs, append=False):
+        """Return a new :class:`_engine.URL` object with the
+        :attr:`_engine.URL.query`
+        parameter dictionary updated by the given sequence of key/value pairs
+
+        E.g.::
+
+            >>> from sqlalchemy.engine import make_url
+            >>> url = make_url("postgresql://user:pass@host/dbname")
+            >>> url = url.update_query_pairs([("alt_host", "host1"), ("alt_host", "host2"), ("ssl_cipher", "/path/to/crt")])
+            >>> str(url)
+            'postgresql://user:pass@host/dbname?alt_host=host1&alt_host=host2&ssl_cipher=%2Fpath%2Fto%2Fcrt'
+
+        :param key_value_pairs: A sequence of tuples containing two strings
+         each.
+
+        :param append: if True, parameters in the existing query string will
+         not be removed; new parameters will be in addition to those present.
+         If left at its default of False, keys present in the given query
+         parameters will replace those of the existing query string.
+
+        .. versionadded:: 1.4
+
+        .. seealso::
+
+            :attr:`_engine.URL.query`
+
+            :meth:`_engine.URL.difference_update_query`
+
+            :meth:`_engine.URL.set`
+
+        """  # noqa: E501
+
+        existing_query = self.query
+        new_keys = {}
+
+        for key, value in key_value_pairs:
+            if key in new_keys:
+                new_keys[key] = util.to_list(new_keys[key])
+                new_keys[key].append(value)
+            else:
+                new_keys[key] = value
+
+        if append:
+            new_query = {}
+
+            for k in new_keys:
+                if k in existing_query:
+                    new_query[k] = util.to_list(
+                        existing_query[k]
+                    ) + util.to_list(new_keys[k])
+                else:
+                    new_query[k] = new_keys[k]
+
+            new_query.update(
+                {
+                    k: existing_query[k]
+                    for k in set(existing_query).difference(new_keys)
+                }
+            )
+        else:
+            new_query = self.query.union(new_keys)
+        return self.set(query=new_query)
+
+    def update_query_dict(self, query_parameters, append=False):
+        """Return a new :class:`_engine.URL` object with the
+        :attr:`_engine.URL.query` parameter dictionary updated by the given
+        dictionary.
+
+        The dictionary typically contains string keys and string values.
+        In order to represent a query parameter that is expressed multiple
+        times, pass a sequence of string values.
+
+        E.g.::
+
+
+            >>> from sqlalchemy.engine import make_url
+            >>> url = make_url("postgresql://user:pass@host/dbname")
+            >>> url = url.update_query_dict({"alt_host": ["host1", "host2"], "ssl_cipher": "/path/to/crt"})
+            >>> str(url)
+            'postgresql://user:pass@host/dbname?alt_host=host1&alt_host=host2&ssl_cipher=%2Fpath%2Fto%2Fcrt'
+
+
+        :param query_parameters: A dictionary with string keys and values
+         that are either strings, or sequences of strings.
+
+        :param append: if True, parameters in the existing query string will
+         not be removed; new parameters will be in addition to those present.
+         If left at its default of False, keys present in the given query
+         parameters will replace those of the existing query string.
+
+
+        .. versionadded:: 1.4
+
+        .. seealso::
+
+            :attr:`_engine.URL.query`
+
+            :meth:`_engine.URL.update_query_string`
+
+            :meth:`_engine.URL.update_query_pairs`
+
+            :meth:`_engine.URL.difference_update_query`
+
+            :meth:`_engine.URL.set`
+
+        """  # noqa: E501
+        return self.update_query_pairs(query_parameters.items(), append=append)
+
+    def difference_update_query(self, names):
+        """
+        Remove the given names from the :attr:`_engine.URL.query` dictionary,
+        returning the new :class:`_engine.URL`.
+
+        E.g.::
+
+            url = url.difference_update_query(['foo', 'bar'])
+
+        Equivalent to using :meth:`_engine.URL.set` as follows::
+
+            url = url.set(
+                query={
+                    key: url.query[key]
+                    for key in set(url.query).difference(['foo', 'bar'])
+                }
+            )
+
+        .. versionadded:: 1.4
+
+        .. seealso::
+
+            :attr:`_engine.URL.query`
+
+            :meth:`_engine.URL.update_query_dict`
+
+            :meth:`_engine.URL.set`
+
+        """
+
+        if not set(names).intersection(self.query):
+            return self
+
+        return URL(
+            self.drivername,
+            self.username,
+            self.password,
+            self.host,
+            self.port,
+            self.database,
+            util.immutabledict(
+                {
+                    key: self.query[key]
+                    for key in set(self.query).difference(names)
+                }
+            ),
+            _new_ok=True,
+        )
+
+    @util.memoized_property
+    def normalized_query(self):
+        """Return the :attr:`_engine.URL.query` dictionary with values normalized
+        into sequences.
+
+        As the :attr:`_engine.URL.query` dictionary may contain either
+        string values or sequences of string values to differentiate between
+        parameters that are specified multiple times in the query string,
+        code that needs to handle multiple parameters generically will wish
+        to use this attribute so that all parameters present are presented
+        as sequences.   Inspiration is from Python's ``urllib.parse.parse_qs``
+        function.  E.g.::
+
+
+            >>> from sqlalchemy.engine import make_url
+            >>> url = make_url("postgresql://user:pass@host/dbname?alt_host=host1&alt_host=host2&ssl_cipher=%2Fpath%2Fto%2Fcrt")
+            >>> url.query
+            immutabledict({'alt_host': ('host1', 'host2'), 'ssl_cipher': '/path/to/crt'})
+            >>> url.normalized_query
+            immutabledict({'alt_host': ('host1', 'host2'), 'ssl_cipher': ('/path/to/crt',)})
+
+        """  # noqa: E501
+
+        return util.immutabledict(
+            {
+                k: (v,) if not isinstance(v, tuple) else v
+                for k, v in self.query.items()
+            }
+        )
+
+    @util.deprecated(
+        "1.4",
+        "The :meth:`_engine.URL.__to_string__ method is deprecated and will "
+        "be removed in a future release.  Please use the "
+        ":meth:`_engine.URL.render_as_string` method.",
+    )
+    def __to_string__(self, hide_password=True):
+        """Render this :class:`_engine.URL` object as a string.
+
+        :param hide_password: Defaults to True.   The password is not shown
+         in the string unless this is set to False.
+
+        """
+        return self.render_as_string(hide_password=hide_password)
+
+    def render_as_string(self, hide_password=True):
+        """Render this :class:`_engine.URL` object as a string.
+
+        This method is used when the ``__str__()`` or ``__repr__()``
+        methods are used.   The method directly includes additional options.
+
+        :param hide_password: Defaults to True.   The password is not shown
+         in the string unless this is set to False.
+
+        """
+        s = self.drivername + "://"
+        if self.username is not None:
+            s += _rfc_1738_quote(self.username)
+            if self.password is not None:
+                s += ":" + (
+                    "***"
+                    if hide_password
+                    else _rfc_1738_quote(str(self.password))
+                )
+            s += "@"
+        if self.host is not None:
+            if ":" in self.host:
+                s += "[%s]" % self.host
+            else:
+                s += self.host
+        if self.port is not None:
+            s += ":" + str(self.port)
+        if self.database is not None:
+            s += "/" + self.database
+        if self.query:
+            keys = list(self.query)
+            keys.sort()
+            s += "?" + "&".join(
+                "%s=%s" % (util.quote_plus(k), util.quote_plus(element))
+                for k in keys
+                for element in util.to_list(self.query[k])
+            )
+        return s
+
+    def __str__(self):
+        return self.render_as_string(hide_password=False)
+
+    def __repr__(self):
+        return self.render_as_string()
+
+    def __copy__(self):
+        return self.__class__.create(
+            self.drivername,
+            self.username,
+            self.password,
+            self.host,
+            self.port,
+            self.database,
+            # note this is an immutabledict of str-> str / tuple of str,
+            # also fully immutable.  does not require deepcopy
+            self.query,
+        )
+
+    def __deepcopy__(self, memo):
+        return self.__copy__()
+
+    def __hash__(self):
+        return hash(str(self))
+
+    def __eq__(self, other):
+        return (
+            isinstance(other, URL)
+            and self.drivername == other.drivername
+            and self.username == other.username
+            and self.password == other.password
+            and self.host == other.host
+            and self.database == other.database
+            and self.query == other.query
+            and self.port == other.port
+        )
+
+    def __ne__(self, other):
+        return not self == other
+
+    def get_backend_name(self):
+        """Return the backend name.
+
+        This is the name that corresponds to the database backend in
+        use, and is the portion of the :attr:`_engine.URL.drivername`
+        that is to the left of the plus sign.
+
+        """
+        if "+" not in self.drivername:
+            return self.drivername
+        else:
+            return self.drivername.split("+")[0]
+
+    def get_driver_name(self):
+        """Return the backend name.
+
+        This is the name that corresponds to the DBAPI driver in
+        use, and is the portion of the :attr:`_engine.URL.drivername`
+        that is to the right of the plus sign.
+
+        If the :attr:`_engine.URL.drivername` does not include a plus sign,
+        then the default :class:`_engine.Dialect` for this :class:`_engine.URL`
+        is imported in order to get the driver name.
+
+        """
+
+        if "+" not in self.drivername:
+            return self.get_dialect().driver
+        else:
+            return self.drivername.split("+")[1]
+
+    def _instantiate_plugins(self, kwargs):
+        plugin_names = util.to_list(self.query.get("plugin", ()))
+        plugin_names += kwargs.get("plugins", [])
+
+        kwargs = dict(kwargs)
+
+        loaded_plugins = [
+            plugins.load(plugin_name)(self, kwargs)
+            for plugin_name in plugin_names
+        ]
+
+        u = self.difference_update_query(["plugin", "plugins"])
+
+        for plugin in loaded_plugins:
+            new_u = plugin.update_url(u)
+            if new_u is not None:
+                u = new_u
+
+        kwargs.pop("plugins", None)
+
+        return u, loaded_plugins, kwargs
+
+    def _get_entrypoint(self):
+        """Return the "entry point" dialect class.
+
+        This is normally the dialect itself except in the case when the
+        returned class implements the get_dialect_cls() method.
+
+        """
+        if "+" not in self.drivername:
+            name = self.drivername
+        else:
+            name = self.drivername.replace("+", ".")
+        cls = registry.load(name)
+        # check for legacy dialects that
+        # would return a module with 'dialect' as the
+        # actual class
+        if (
+            hasattr(cls, "dialect")
+            and isinstance(cls.dialect, type)
+            and issubclass(cls.dialect, Dialect)
+        ):
+            return cls.dialect
+        else:
+            return cls
+
+    def get_dialect(self):
+        """Return the SQLAlchemy :class:`_engine.Dialect` class corresponding
+        to this URL's driver name.
+
+        """
+        entrypoint = self._get_entrypoint()
+        dialect_cls = entrypoint.get_dialect_cls(self)
+        return dialect_cls
+
+    def translate_connect_args(self, names=None, **kw):
+        r"""Translate url attributes into a dictionary of connection arguments.
+
+        Returns attributes of this url (`host`, `database`, `username`,
+        `password`, `port`) as a plain dictionary.  The attribute names are
+        used as the keys by default.  Unset or false attributes are omitted
+        from the final dictionary.
+
+        :param \**kw: Optional, alternate key names for url attributes.
+
+        :param names: Deprecated.  Same purpose as the keyword-based alternate
+            names, but correlates the name to the original positionally.
+        """
+
+        if names is not None:
+            util.warn_deprecated(
+                "The `URL.translate_connect_args.name`s parameter is "
+                "deprecated. Please pass the "
+                "alternate names as kw arguments.",
+                "1.4",
+            )
+
+        translated = {}
+        attribute_names = ["host", "database", "username", "password", "port"]
+        for sname in attribute_names:
+            if names:
+                name = names.pop(0)
+            elif sname in kw:
+                name = kw[sname]
+            else:
+                name = sname
+            if name is not None and getattr(self, sname, False):
+                if sname == "password":
+                    translated[name] = str(getattr(self, sname))
+                else:
+                    translated[name] = getattr(self, sname)
+
+        return translated
+
+
+def make_url(name_or_url):
+    """Given a string or unicode instance, produce a new URL instance.
+
+    The given string is parsed according to the RFC 1738 spec.  If an
+    existing URL object is passed, just returns the object.
+    """
+
+    if isinstance(name_or_url, util.string_types):
+        return _parse_rfc1738_args(name_or_url)
+    else:
+        return name_or_url
+
+
+def _parse_rfc1738_args(name):
+    pattern = re.compile(
+        r"""
+            (?P<name>[\w\+]+)://
+            (?:
+                (?P<username>[^:/]*)
+                (?::(?P<password>[^@]*))?
+            @)?
+            (?:
+                (?:
+                    \[(?P<ipv6host>[^/\?]+)\] |
+                    (?P<ipv4host>[^/:\?]+)
+                )?
+                (?::(?P<port>[^/\?]*))?
+            )?
+            (?:/(?P<database>[^\?]*))?
+            (?:\?(?P<query>.*))?
+            """,
+        re.X,
+    )
+
+    m = pattern.match(name)
+    if m is not None:
+        components = m.groupdict()
+        if components["query"] is not None:
+            query = {}
+
+            for key, value in util.parse_qsl(components["query"]):
+                if util.py2k:
+                    key = key.encode("ascii")
+                if key in query:
+                    query[key] = util.to_list(query[key])
+                    query[key].append(value)
+                else:
+                    query[key] = value
+        else:
+            query = None
+        components["query"] = query
+
+        if components["username"] is not None:
+            components["username"] = _rfc_1738_unquote(components["username"])
+
+        if components["password"] is not None:
+            components["password"] = _rfc_1738_unquote(components["password"])
+
+        ipv4host = components.pop("ipv4host")
+        ipv6host = components.pop("ipv6host")
+        components["host"] = ipv4host or ipv6host
+        name = components.pop("name")
+
+        if components["port"]:
+            components["port"] = int(components["port"])
+
+        return URL.create(name, **components)
+
+    else:
+        raise exc.ArgumentError(
+            "Could not parse rfc1738 URL from string '%s'" % name
+        )
+
+
+def _rfc_1738_quote(text):
+    return re.sub(r"[:@/]", lambda m: "%%%X" % ord(m.group(0)), text)
+
+
+def _rfc_1738_unquote(text):
+    return util.unquote(text)
+
+
+def _parse_keyvalue_args(name):
+    m = re.match(r"(\w+)://(.*)", name)
+    if m is not None:
+        (name, args) = m.group(1, 2)
+        opts = dict(util.parse_qsl(args))
+        return URL(name, *opts)
+    else:
+        return None

lib/sqlalchemy/engine/util.py

@@ -0,0 +1,253 @@
+# engine/util.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from .. import exc
+from .. import util
+from ..util import collections_abc
+from ..util import immutabledict
+
+
+def connection_memoize(key):
+    """Decorator, memoize a function in a connection.info stash.
+
+    Only applicable to functions which take no arguments other than a
+    connection.  The memo will be stored in ``connection.info[key]``.
+    """
+
+    @util.decorator
+    def decorated(fn, self, connection):
+        connection = connection.connect()
+        try:
+            return connection.info[key]
+        except KeyError:
+            connection.info[key] = val = fn(self, connection)
+            return val
+
+    return decorated
+
+
+_no_tuple = ()
+_no_kw = util.immutabledict()
+
+
+def _distill_params(connection, multiparams, params):
+    r"""Given arguments from the calling form \*multiparams, \**params,
+    return a list of bind parameter structures, usually a list of
+    dictionaries.
+
+    In the case of 'raw' execution which accepts positional parameters,
+    it may be a list of tuples or lists.
+
+    """
+
+    if not multiparams:
+        if params:
+            connection._warn_for_legacy_exec_format()
+            return [params]
+        else:
+            return []
+    elif len(multiparams) == 1:
+        zero = multiparams[0]
+        if isinstance(zero, (list, tuple)):
+            if (
+                not zero
+                or hasattr(zero[0], "__iter__")
+                and not hasattr(zero[0], "strip")
+            ):
+                # execute(stmt, [{}, {}, {}, ...])
+                # execute(stmt, [(), (), (), ...])
+                return zero
+            else:
+                # this is used by exec_driver_sql only, so a deprecation
+                # warning would already be coming from passing a plain
+                # textual statement with positional parameters to
+                # execute().
+                # execute(stmt, ("value", "value"))
+                return [zero]
+        elif hasattr(zero, "keys"):
+            # execute(stmt, {"key":"value"})
+            return [zero]
+        else:
+            connection._warn_for_legacy_exec_format()
+            # execute(stmt, "value")
+            return [[zero]]
+    else:
+        connection._warn_for_legacy_exec_format()
+        if hasattr(multiparams[0], "__iter__") and not hasattr(
+            multiparams[0], "strip"
+        ):
+            return multiparams
+        else:
+            return [multiparams]
+
+
+def _distill_cursor_params(connection, multiparams, params):
+    """_distill_params without any warnings.  more appropriate for
+    "cursor" params that can include tuple arguments, lists of tuples,
+    etc.
+
+    """
+
+    if not multiparams:
+        if params:
+            return [params]
+        else:
+            return []
+    elif len(multiparams) == 1:
+        zero = multiparams[0]
+        if isinstance(zero, (list, tuple)):
+            if (
+                not zero
+                or hasattr(zero[0], "__iter__")
+                and not hasattr(zero[0], "strip")
+            ):
+                # execute(stmt, [{}, {}, {}, ...])
+                # execute(stmt, [(), (), (), ...])
+                return zero
+            else:
+                # this is used by exec_driver_sql only, so a deprecation
+                # warning would already be coming from passing a plain
+                # textual statement with positional parameters to
+                # execute().
+                # execute(stmt, ("value", "value"))
+
+                return [zero]
+        elif hasattr(zero, "keys"):
+            # execute(stmt, {"key":"value"})
+            return [zero]
+        else:
+            # execute(stmt, "value")
+            return [[zero]]
+    else:
+        if hasattr(multiparams[0], "__iter__") and not hasattr(
+            multiparams[0], "strip"
+        ):
+            return multiparams
+        else:
+            return [multiparams]
+
+
+def _distill_params_20(params):
+    if params is None:
+        return _no_tuple, _no_kw
+    elif isinstance(params, list):
+        # collections_abc.MutableSequence): # avoid abc.__instancecheck__
+        if params and not isinstance(
+            params[0], (collections_abc.Mapping, tuple)
+        ):
+            raise exc.ArgumentError(
+                "List argument must consist only of tuples or dictionaries"
+            )
+
+        return (params,), _no_kw
+    elif isinstance(
+        params,
+        (tuple, dict, immutabledict),
+        # only do abc.__instancecheck__ for Mapping after we've checked
+        # for plain dictionaries and would otherwise raise
+    ) or isinstance(params, collections_abc.Mapping):
+        return (params,), _no_kw
+    else:
+        raise exc.ArgumentError("mapping or sequence expected for parameters")
+
+
+class TransactionalContext(object):
+    """Apply Python context manager behavior to transaction objects.
+
+    Performs validation to ensure the subject of the transaction is not
+    used if the transaction were ended prematurely.
+
+    """
+
+    _trans_subject = None
+
+    def _transaction_is_active(self):
+        raise NotImplementedError()
+
+    def _transaction_is_closed(self):
+        raise NotImplementedError()
+
+    def _rollback_can_be_called(self):
+        """indicates the object is in a state that is known to be acceptable
+        for rollback() to be called.
+
+        This does not necessarily mean rollback() will succeed or not raise
+        an error, just that there is currently no state detected that indicates
+        rollback() would fail or emit warnings.
+
+        It also does not mean that there's a transaction in progress, as
+        it is usually safe to call rollback() even if no transaction is
+        present.
+
+        .. versionadded:: 1.4.28
+
+        """
+        raise NotImplementedError()
+
+    def _get_subject(self):
+        raise NotImplementedError()
+
+    @classmethod
+    def _trans_ctx_check(cls, subject):
+        trans_context = subject._trans_context_manager
+        if trans_context:
+            if not trans_context._transaction_is_active():
+                raise exc.InvalidRequestError(
+                    "Can't operate on closed transaction inside context "
+                    "manager.  Please complete the context manager "
+                    "before emitting further commands."
+                )
+
+    def __enter__(self):
+        subject = self._get_subject()
+
+        # none for outer transaction, may be non-None for nested
+        # savepoint, legacy nesting cases
+        trans_context = subject._trans_context_manager
+        self._outer_trans_ctx = trans_context
+
+        self._trans_subject = subject
+        subject._trans_context_manager = self
+        return self
+
+    def __exit__(self, type_, value, traceback):
+        subject = self._trans_subject
+
+        # simplistically we could assume that
+        # "subject._trans_context_manager is self".  However, any calling
+        # code that is manipulating __exit__ directly would break this
+        # assumption.  alembic context manager
+        # is an example of partial use that just calls __exit__ and
+        # not __enter__ at the moment.  it's safe to assume this is being done
+        # in the wild also
+        out_of_band_exit = (
+            subject is None or subject._trans_context_manager is not self
+        )
+
+        if type_ is None and self._transaction_is_active():
+            try:
+                self.commit()
+            except:
+                with util.safe_reraise():
+                    if self._rollback_can_be_called():
+                        self.rollback()
+            finally:
+                if not out_of_band_exit:
+                    subject._trans_context_manager = self._outer_trans_ctx
+                self._trans_subject = self._outer_trans_ctx = None
+        else:
+            try:
+                if not self._transaction_is_active():
+                    if not self._transaction_is_closed():
+                        self.close()
+                else:
+                    if self._rollback_can_be_called():
+                        self.rollback()
+            finally:
+                if not out_of_band_exit:
+                    subject._trans_context_manager = self._outer_trans_ctx
+                self._trans_subject = self._outer_trans_ctx = None

lib/sqlalchemy/event/__init__.py

@@ -0,0 +1,17 @@
+# event/__init__.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from .api import CANCEL
+from .api import contains
+from .api import listen
+from .api import listens_for
+from .api import NO_RETVAL
+from .api import remove
+from .attr import RefCollection
+from .base import dispatcher
+from .base import Events
+from .legacy import _legacy_signature

lib/sqlalchemy/event/api.py

@@ -0,0 +1,219 @@
+# event/api.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""Public API functions for the event system.
+
+"""
+from __future__ import absolute_import
+
+from .base import _registrars
+from .registry import _EventKey
+from .. import exc
+from .. import util
+
+
+CANCEL = util.symbol("CANCEL")
+NO_RETVAL = util.symbol("NO_RETVAL")
+
+
+def _event_key(target, identifier, fn):
+    for evt_cls in _registrars[identifier]:
+        tgt = evt_cls._accept_with(target)
+        if tgt is not None:
+            return _EventKey(target, identifier, fn, tgt)
+    else:
+        raise exc.InvalidRequestError(
+            "No such event '%s' for target '%s'" % (identifier, target)
+        )
+
+
+def listen(target, identifier, fn, *args, **kw):
+    """Register a listener function for the given target.
+
+    The :func:`.listen` function is part of the primary interface for the
+    SQLAlchemy event system, documented at :ref:`event_toplevel`.
+
+    e.g.::
+
+        from sqlalchemy import event
+        from sqlalchemy.schema import UniqueConstraint
+
+        def unique_constraint_name(const, table):
+            const.name = "uq_%s_%s" % (
+                table.name,
+                list(const.columns)[0].name
+            )
+        event.listen(
+                UniqueConstraint,
+                "after_parent_attach",
+                unique_constraint_name)
+
+    :param bool insert: The default behavior for event handlers is to append
+      the decorated user defined function to an internal list of registered
+      event listeners upon discovery. If a user registers a function with
+      ``insert=True``, SQLAlchemy will insert (prepend) the function to the
+      internal list upon discovery. This feature is not typically used or
+      recommended by the SQLAlchemy maintainers, but is provided to ensure
+      certain user defined functions can run before others, such as when
+      :ref:`Changing the sql_mode in MySQL <mysql_sql_mode>`.
+
+    :param bool named: When using named argument passing, the names listed in
+      the function argument specification will be used as keys in the
+      dictionary.
+      See :ref:`event_named_argument_styles`.
+
+    :param bool once: Private/Internal API usage. Deprecated.  This parameter
+      would provide that an event function would run only once per given
+      target. It does not however imply automatic de-registration of the
+      listener function; associating an arbitrarily high number of listeners
+      without explicitly removing them will cause memory to grow unbounded even
+      if ``once=True`` is specified.
+
+    :param bool propagate: The ``propagate`` kwarg is available when working
+      with ORM instrumentation and mapping events.
+      See :class:`_ormevent.MapperEvents` and
+      :meth:`_ormevent.MapperEvents.before_mapper_configured` for examples.
+
+    :param bool retval: This flag applies only to specific event listeners,
+      each of which includes documentation explaining when it should be used.
+      By default, no listener ever requires a return value.
+      However, some listeners do support special behaviors for return values,
+      and include in their documentation that the ``retval=True`` flag is
+      necessary for a return value to be processed.
+
+      Event listener suites that make use of :paramref:`_event.listen.retval`
+      include :class:`_events.ConnectionEvents` and
+      :class:`_ormevent.AttributeEvents`.
+
+    .. note::
+
+        The :func:`.listen` function cannot be called at the same time
+        that the target event is being run.   This has implications
+        for thread safety, and also means an event cannot be added
+        from inside the listener function for itself.  The list of
+        events to be run are present inside of a mutable collection
+        that can't be changed during iteration.
+
+        Event registration and removal is not intended to be a "high
+        velocity" operation; it is a configurational operation.  For
+        systems that need to quickly associate and deassociate with
+        events at high scale, use a mutable structure that is handled
+        from inside of a single listener.
+
+    .. seealso::
+
+        :func:`.listens_for`
+
+        :func:`.remove`
+
+    """
+
+    _event_key(target, identifier, fn).listen(*args, **kw)
+
+
+def listens_for(target, identifier, *args, **kw):
+    """Decorate a function as a listener for the given target + identifier.
+
+    The :func:`.listens_for` decorator is part of the primary interface for the
+    SQLAlchemy event system, documented at :ref:`event_toplevel`.
+
+    This function generally shares the same kwargs as :func:`.listens`.
+
+    e.g.::
+
+        from sqlalchemy import event
+        from sqlalchemy.schema import UniqueConstraint
+
+        @event.listens_for(UniqueConstraint, "after_parent_attach")
+        def unique_constraint_name(const, table):
+            const.name = "uq_%s_%s" % (
+                table.name,
+                list(const.columns)[0].name
+            )
+
+    A given function can also be invoked for only the first invocation
+    of the event using the ``once`` argument::
+
+        @event.listens_for(Mapper, "before_configure", once=True)
+        def on_config():
+            do_config()
+
+
+    .. warning:: The ``once`` argument does not imply automatic de-registration
+       of the listener function after it has been invoked a first time; a
+       listener entry will remain associated with the target object.
+       Associating an arbitrarily high number of listeners without explicitly
+       removing them will cause memory to grow unbounded even if ``once=True``
+       is specified.
+
+    .. seealso::
+
+        :func:`.listen` - general description of event listening
+
+    """
+
+    def decorate(fn):
+        listen(target, identifier, fn, *args, **kw)
+        return fn
+
+    return decorate
+
+
+def remove(target, identifier, fn):
+    """Remove an event listener.
+
+    The arguments here should match exactly those which were sent to
+    :func:`.listen`; all the event registration which proceeded as a result
+    of this call will be reverted by calling :func:`.remove` with the same
+    arguments.
+
+    e.g.::
+
+        # if a function was registered like this...
+        @event.listens_for(SomeMappedClass, "before_insert", propagate=True)
+        def my_listener_function(*arg):
+            pass
+
+        # ... it's removed like this
+        event.remove(SomeMappedClass, "before_insert", my_listener_function)
+
+    Above, the listener function associated with ``SomeMappedClass`` was also
+    propagated to subclasses of ``SomeMappedClass``; the :func:`.remove`
+    function will revert all of these operations.
+
+    .. note::
+
+        The :func:`.remove` function cannot be called at the same time
+        that the target event is being run.   This has implications
+        for thread safety, and also means an event cannot be removed
+        from inside the listener function for itself.  The list of
+        events to be run are present inside of a mutable collection
+        that can't be changed during iteration.
+
+        Event registration and removal is not intended to be a "high
+        velocity" operation; it is a configurational operation.  For
+        systems that need to quickly associate and deassociate with
+        events at high scale, use a mutable structure that is handled
+        from inside of a single listener.
+
+        .. versionchanged:: 1.0.0 - a ``collections.deque()`` object is now
+           used as the container for the list of events, which explicitly
+           disallows collection mutation while the collection is being
+           iterated.
+
+    .. seealso::
+
+        :func:`.listen`
+
+    """
+    _event_key(target, identifier, fn).remove()
+
+
+def contains(target, identifier, fn):
+    """Return True if the given target/ident/fn is set up to listen."""
+
+    return _event_key(target, identifier, fn).contains()

lib/sqlalchemy/event/attr.py

@@ -0,0 +1,468 @@
+# event/attr.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""Attribute implementation for _Dispatch classes.
+
+The various listener targets for a particular event class are represented
+as attributes, which refer to collections of listeners to be fired off.
+These collections can exist at the class level as well as at the instance
+level.  An event is fired off using code like this::
+
+    some_object.dispatch.first_connect(arg1, arg2)
+
+Above, ``some_object.dispatch`` would be an instance of ``_Dispatch`` and
+``first_connect`` is typically an instance of ``_ListenerCollection``
+if event listeners are present, or ``_EmptyListener`` if none are present.
+
+The attribute mechanics here spend effort trying to ensure listener functions
+are available with a minimum of function call overhead, that unnecessary
+objects aren't created (i.e. many empty per-instance listener collections),
+as well as that everything is garbage collectable when owning references are
+lost.  Other features such as "propagation" of listener functions across
+many ``_Dispatch`` instances, "joining" of multiple ``_Dispatch`` instances,
+as well as support for subclass propagation (e.g. events assigned to
+``Pool`` vs. ``QueuePool``) are all implemented here.
+
+"""
+
+from __future__ import absolute_import
+from __future__ import with_statement
+
+import collections
+from itertools import chain
+import weakref
+
+from . import legacy
+from . import registry
+from .. import exc
+from .. import util
+from ..util import threading
+from ..util.concurrency import AsyncAdaptedLock
+
+
+class RefCollection(util.MemoizedSlots):
+    __slots__ = ("ref",)
+
+    def _memoized_attr_ref(self):
+        return weakref.ref(self, registry._collection_gced)
+
+
+class _empty_collection(object):
+    def append(self, element):
+        pass
+
+    def extend(self, other):
+        pass
+
+    def remove(self, element):
+        pass
+
+    def __iter__(self):
+        return iter([])
+
+    def clear(self):
+        pass
+
+
+class _ClsLevelDispatch(RefCollection):
+    """Class-level events on :class:`._Dispatch` classes."""
+
+    __slots__ = (
+        "clsname",
+        "name",
+        "arg_names",
+        "has_kw",
+        "legacy_signatures",
+        "_clslevel",
+        "__weakref__",
+    )
+
+    def __init__(self, parent_dispatch_cls, fn):
+        self.name = fn.__name__
+        self.clsname = parent_dispatch_cls.__name__
+        argspec = util.inspect_getfullargspec(fn)
+        self.arg_names = argspec.args[1:]
+        self.has_kw = bool(argspec.varkw)
+        self.legacy_signatures = list(
+            reversed(
+                sorted(
+                    getattr(fn, "_legacy_signatures", []), key=lambda s: s[0]
+                )
+            )
+        )
+        fn.__doc__ = legacy._augment_fn_docs(self, parent_dispatch_cls, fn)
+
+        self._clslevel = weakref.WeakKeyDictionary()
+
+    def _adjust_fn_spec(self, fn, named):
+        if named:
+            fn = self._wrap_fn_for_kw(fn)
+        if self.legacy_signatures:
+            try:
+                argspec = util.get_callable_argspec(fn, no_self=True)
+            except TypeError:
+                pass
+            else:
+                fn = legacy._wrap_fn_for_legacy(self, fn, argspec)
+        return fn
+
+    def _wrap_fn_for_kw(self, fn):
+        def wrap_kw(*args, **kw):
+            argdict = dict(zip(self.arg_names, args))
+            argdict.update(kw)
+            return fn(**argdict)
+
+        return wrap_kw
+
+    def insert(self, event_key, propagate):
+        target = event_key.dispatch_target
+        assert isinstance(
+            target, type
+        ), "Class-level Event targets must be classes."
+        if not getattr(target, "_sa_propagate_class_events", True):
+            raise exc.InvalidRequestError(
+                "Can't assign an event directly to the %s class" % target
+            )
+
+        for cls in util.walk_subclasses(target):
+            if cls is not target and cls not in self._clslevel:
+                self.update_subclass(cls)
+            else:
+                if cls not in self._clslevel:
+                    self._assign_cls_collection(cls)
+                self._clslevel[cls].appendleft(event_key._listen_fn)
+        registry._stored_in_collection(event_key, self)
+
+    def append(self, event_key, propagate):
+        target = event_key.dispatch_target
+        assert isinstance(
+            target, type
+        ), "Class-level Event targets must be classes."
+        if not getattr(target, "_sa_propagate_class_events", True):
+            raise exc.InvalidRequestError(
+                "Can't assign an event directly to the %s class" % target
+            )
+        for cls in util.walk_subclasses(target):
+            if cls is not target and cls not in self._clslevel:
+                self.update_subclass(cls)
+            else:
+                if cls not in self._clslevel:
+                    self._assign_cls_collection(cls)
+                self._clslevel[cls].append(event_key._listen_fn)
+        registry._stored_in_collection(event_key, self)
+
+    def _assign_cls_collection(self, target):
+        if getattr(target, "_sa_propagate_class_events", True):
+            self._clslevel[target] = collections.deque()
+        else:
+            self._clslevel[target] = _empty_collection()
+
+    def update_subclass(self, target):
+        if target not in self._clslevel:
+            self._assign_cls_collection(target)
+        clslevel = self._clslevel[target]
+        for cls in target.__mro__[1:]:
+            if cls in self._clslevel:
+                clslevel.extend(
+                    [fn for fn in self._clslevel[cls] if fn not in clslevel]
+                )
+
+    def remove(self, event_key):
+        target = event_key.dispatch_target
+        for cls in util.walk_subclasses(target):
+            if cls in self._clslevel:
+                self._clslevel[cls].remove(event_key._listen_fn)
+        registry._removed_from_collection(event_key, self)
+
+    def clear(self):
+        """Clear all class level listeners"""
+
+        to_clear = set()
+        for dispatcher in self._clslevel.values():
+            to_clear.update(dispatcher)
+            dispatcher.clear()
+        registry._clear(self, to_clear)
+
+    def for_modify(self, obj):
+        """Return an event collection which can be modified.
+
+        For _ClsLevelDispatch at the class level of
+        a dispatcher, this returns self.
+
+        """
+        return self
+
+
+class _InstanceLevelDispatch(RefCollection):
+    __slots__ = ()
+
+    def _adjust_fn_spec(self, fn, named):
+        return self.parent._adjust_fn_spec(fn, named)
+
+
+class _EmptyListener(_InstanceLevelDispatch):
+    """Serves as a proxy interface to the events
+    served by a _ClsLevelDispatch, when there are no
+    instance-level events present.
+
+    Is replaced by _ListenerCollection when instance-level
+    events are added.
+
+    """
+
+    propagate = frozenset()
+    listeners = ()
+
+    __slots__ = "parent", "parent_listeners", "name"
+
+    def __init__(self, parent, target_cls):
+        if target_cls not in parent._clslevel:
+            parent.update_subclass(target_cls)
+        self.parent = parent  # _ClsLevelDispatch
+        self.parent_listeners = parent._clslevel[target_cls]
+        self.name = parent.name
+
+    def for_modify(self, obj):
+        """Return an event collection which can be modified.
+
+        For _EmptyListener at the instance level of
+        a dispatcher, this generates a new
+        _ListenerCollection, applies it to the instance,
+        and returns it.
+
+        """
+        result = _ListenerCollection(self.parent, obj._instance_cls)
+        if getattr(obj, self.name) is self:
+            setattr(obj, self.name, result)
+        else:
+            assert isinstance(getattr(obj, self.name), _JoinedListener)
+        return result
+
+    def _needs_modify(self, *args, **kw):
+        raise NotImplementedError("need to call for_modify()")
+
+    exec_once = (
+        exec_once_unless_exception
+    ) = insert = append = remove = clear = _needs_modify
+
+    def __call__(self, *args, **kw):
+        """Execute this event."""
+
+        for fn in self.parent_listeners:
+            fn(*args, **kw)
+
+    def __len__(self):
+        return len(self.parent_listeners)
+
+    def __iter__(self):
+        return iter(self.parent_listeners)
+
+    def __bool__(self):
+        return bool(self.parent_listeners)
+
+    __nonzero__ = __bool__
+
+
+class _CompoundListener(_InstanceLevelDispatch):
+    __slots__ = "_exec_once_mutex", "_exec_once", "_exec_w_sync_once"
+
+    def _set_asyncio(self):
+        self._exec_once_mutex = AsyncAdaptedLock()
+
+    def _memoized_attr__exec_once_mutex(self):
+        return threading.Lock()
+
+    def _exec_once_impl(self, retry_on_exception, *args, **kw):
+        with self._exec_once_mutex:
+            if not self._exec_once:
+                try:
+                    self(*args, **kw)
+                    exception = False
+                except:
+                    exception = True
+                    raise
+                finally:
+                    if not exception or not retry_on_exception:
+                        self._exec_once = True
+
+    def exec_once(self, *args, **kw):
+        """Execute this event, but only if it has not been
+        executed already for this collection."""
+
+        if not self._exec_once:
+            self._exec_once_impl(False, *args, **kw)
+
+    def exec_once_unless_exception(self, *args, **kw):
+        """Execute this event, but only if it has not been
+        executed already for this collection, or was called
+        by a previous exec_once_unless_exception call and
+        raised an exception.
+
+        If exec_once was already called, then this method will never run
+        the callable regardless of whether it raised or not.
+
+        .. versionadded:: 1.3.8
+
+        """
+        if not self._exec_once:
+            self._exec_once_impl(True, *args, **kw)
+
+    def _exec_w_sync_on_first_run(self, *args, **kw):
+        """Execute this event, and use a mutex if it has not been
+        executed already for this collection, or was called
+        by a previous _exec_w_sync_on_first_run call and
+        raised an exception.
+
+        If _exec_w_sync_on_first_run was already called and didn't raise an
+        exception, then a mutex is not used.
+
+        .. versionadded:: 1.4.11
+
+        """
+        if not self._exec_w_sync_once:
+            with self._exec_once_mutex:
+                try:
+                    self(*args, **kw)
+                except:
+                    raise
+                else:
+                    self._exec_w_sync_once = True
+        else:
+            self(*args, **kw)
+
+    def __call__(self, *args, **kw):
+        """Execute this event."""
+
+        for fn in self.parent_listeners:
+            fn(*args, **kw)
+        for fn in self.listeners:
+            fn(*args, **kw)
+
+    def __len__(self):
+        return len(self.parent_listeners) + len(self.listeners)
+
+    def __iter__(self):
+        return chain(self.parent_listeners, self.listeners)
+
+    def __bool__(self):
+        return bool(self.listeners or self.parent_listeners)
+
+    __nonzero__ = __bool__
+
+
+class _ListenerCollection(_CompoundListener):
+    """Instance-level attributes on instances of :class:`._Dispatch`.
+
+    Represents a collection of listeners.
+
+    As of 0.7.9, _ListenerCollection is only first
+    created via the _EmptyListener.for_modify() method.
+
+    """
+
+    __slots__ = (
+        "parent_listeners",
+        "parent",
+        "name",
+        "listeners",
+        "propagate",
+        "__weakref__",
+    )
+
+    def __init__(self, parent, target_cls):
+        if target_cls not in parent._clslevel:
+            parent.update_subclass(target_cls)
+        self._exec_once = False
+        self._exec_w_sync_once = False
+        self.parent_listeners = parent._clslevel[target_cls]
+        self.parent = parent
+        self.name = parent.name
+        self.listeners = collections.deque()
+        self.propagate = set()
+
+    def for_modify(self, obj):
+        """Return an event collection which can be modified.
+
+        For _ListenerCollection at the instance level of
+        a dispatcher, this returns self.
+
+        """
+        return self
+
+    def _update(self, other, only_propagate=True):
+        """Populate from the listeners in another :class:`_Dispatch`
+        object."""
+
+        existing_listeners = self.listeners
+        existing_listener_set = set(existing_listeners)
+        self.propagate.update(other.propagate)
+        other_listeners = [
+            l
+            for l in other.listeners
+            if l not in existing_listener_set
+            and not only_propagate
+            or l in self.propagate
+        ]
+
+        existing_listeners.extend(other_listeners)
+
+        to_associate = other.propagate.union(other_listeners)
+        registry._stored_in_collection_multi(self, other, to_associate)
+
+    def insert(self, event_key, propagate):
+        if event_key.prepend_to_list(self, self.listeners):
+            if propagate:
+                self.propagate.add(event_key._listen_fn)
+
+    def append(self, event_key, propagate):
+        if event_key.append_to_list(self, self.listeners):
+            if propagate:
+                self.propagate.add(event_key._listen_fn)
+
+    def remove(self, event_key):
+        self.listeners.remove(event_key._listen_fn)
+        self.propagate.discard(event_key._listen_fn)
+        registry._removed_from_collection(event_key, self)
+
+    def clear(self):
+        registry._clear(self, self.listeners)
+        self.propagate.clear()
+        self.listeners.clear()
+
+
+class _JoinedListener(_CompoundListener):
+    __slots__ = "parent", "name", "local", "parent_listeners"
+
+    def __init__(self, parent, name, local):
+        self._exec_once = False
+        self.parent = parent
+        self.name = name
+        self.local = local
+        self.parent_listeners = self.local
+
+    @property
+    def listeners(self):
+        return getattr(self.parent, self.name)
+
+    def _adjust_fn_spec(self, fn, named):
+        return self.local._adjust_fn_spec(fn, named)
+
+    def for_modify(self, obj):
+        self.local = self.parent_listeners = self.local.for_modify(obj)
+        return self
+
+    def insert(self, event_key, propagate):
+        self.local.insert(event_key, propagate)
+
+    def append(self, event_key, propagate):
+        self.local.append(event_key, propagate)
+
+    def remove(self, event_key):
+        self.local.remove(event_key)
+
+    def clear(self):
+        raise NotImplementedError()

lib/sqlalchemy/event/base.py

@@ -0,0 +1,345 @@
+# event/base.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""Base implementation classes.
+
+The public-facing ``Events`` serves as the base class for an event interface;
+its public attributes represent different kinds of events.   These attributes
+are mirrored onto a ``_Dispatch`` class, which serves as a container for
+collections of listener functions.   These collections are represented both
+at the class level of a particular ``_Dispatch`` class as well as within
+instances of ``_Dispatch``.
+
+"""
+from __future__ import absolute_import
+
+import weakref
+
+from .attr import _ClsLevelDispatch
+from .attr import _EmptyListener
+from .attr import _JoinedListener
+from .. import util
+
+
+_registrars = util.defaultdict(list)
+
+
+def _is_event_name(name):
+    # _sa_event prefix is special to support internal-only event names.
+    # most event names are just plain method names that aren't
+    # underscored.
+
+    return (
+        not name.startswith("_") and name != "dispatch"
+    ) or name.startswith("_sa_event")
+
+
+class _UnpickleDispatch(object):
+    """Serializable callable that re-generates an instance of
+    :class:`_Dispatch` given a particular :class:`.Events` subclass.
+
+    """
+
+    def __call__(self, _instance_cls):
+        for cls in _instance_cls.__mro__:
+            if "dispatch" in cls.__dict__:
+                return cls.__dict__["dispatch"].dispatch._for_class(
+                    _instance_cls
+                )
+        else:
+            raise AttributeError("No class with a 'dispatch' member present.")
+
+
+class _Dispatch(object):
+    """Mirror the event listening definitions of an Events class with
+    listener collections.
+
+    Classes which define a "dispatch" member will return a
+    non-instantiated :class:`._Dispatch` subclass when the member
+    is accessed at the class level.  When the "dispatch" member is
+    accessed at the instance level of its owner, an instance
+    of the :class:`._Dispatch` class is returned.
+
+    A :class:`._Dispatch` class is generated for each :class:`.Events`
+    class defined, by the :func:`._create_dispatcher_class` function.
+    The original :class:`.Events` classes remain untouched.
+    This decouples the construction of :class:`.Events` subclasses from
+    the implementation used by the event internals, and allows
+    inspecting tools like Sphinx to work in an unsurprising
+    way against the public API.
+
+    """
+
+    # In one ORM edge case, an attribute is added to _Dispatch,
+    # so __dict__ is used in just that case and potentially others.
+    __slots__ = "_parent", "_instance_cls", "__dict__", "_empty_listeners"
+
+    _empty_listener_reg = weakref.WeakKeyDictionary()
+
+    def __init__(self, parent, instance_cls=None):
+        self._parent = parent
+        self._instance_cls = instance_cls
+
+        if instance_cls:
+            try:
+                self._empty_listeners = self._empty_listener_reg[instance_cls]
+            except KeyError:
+                self._empty_listeners = self._empty_listener_reg[
+                    instance_cls
+                ] = {
+                    ls.name: _EmptyListener(ls, instance_cls)
+                    for ls in parent._event_descriptors
+                }
+        else:
+            self._empty_listeners = {}
+
+    def __getattr__(self, name):
+        # Assign EmptyListeners as attributes on demand
+        # to reduce startup time for new dispatch objects.
+        try:
+            ls = self._empty_listeners[name]
+        except KeyError:
+            raise AttributeError(name)
+        else:
+            setattr(self, ls.name, ls)
+            return ls
+
+    @property
+    def _event_descriptors(self):
+        for k in self._event_names:
+            # Yield _ClsLevelDispatch related
+            # to relevant event name.
+            yield getattr(self, k)
+
+    @property
+    def _listen(self):
+        return self._events._listen
+
+    def _for_class(self, instance_cls):
+        return self.__class__(self, instance_cls)
+
+    def _for_instance(self, instance):
+        instance_cls = instance.__class__
+        return self._for_class(instance_cls)
+
+    def _join(self, other):
+        """Create a 'join' of this :class:`._Dispatch` and another.
+
+        This new dispatcher will dispatch events to both
+        :class:`._Dispatch` objects.
+
+        """
+        if "_joined_dispatch_cls" not in self.__class__.__dict__:
+            cls = type(
+                "Joined%s" % self.__class__.__name__,
+                (_JoinedDispatcher,),
+                {"__slots__": self._event_names},
+            )
+
+            self.__class__._joined_dispatch_cls = cls
+        return self._joined_dispatch_cls(self, other)
+
+    def __reduce__(self):
+        return _UnpickleDispatch(), (self._instance_cls,)
+
+    def _update(self, other, only_propagate=True):
+        """Populate from the listeners in another :class:`_Dispatch`
+        object."""
+        for ls in other._event_descriptors:
+            if isinstance(ls, _EmptyListener):
+                continue
+            getattr(self, ls.name).for_modify(self)._update(
+                ls, only_propagate=only_propagate
+            )
+
+    def _clear(self):
+        for ls in self._event_descriptors:
+            ls.for_modify(self).clear()
+
+
+class _EventMeta(type):
+    """Intercept new Event subclasses and create
+    associated _Dispatch classes."""
+
+    def __init__(cls, classname, bases, dict_):
+        _create_dispatcher_class(cls, classname, bases, dict_)
+        type.__init__(cls, classname, bases, dict_)
+
+
+def _create_dispatcher_class(cls, classname, bases, dict_):
+    """Create a :class:`._Dispatch` class corresponding to an
+    :class:`.Events` class."""
+
+    # there's all kinds of ways to do this,
+    # i.e. make a Dispatch class that shares the '_listen' method
+    # of the Event class, this is the straight monkeypatch.
+    if hasattr(cls, "dispatch"):
+        dispatch_base = cls.dispatch.__class__
+    else:
+        dispatch_base = _Dispatch
+
+    event_names = [k for k in dict_ if _is_event_name(k)]
+    dispatch_cls = type(
+        "%sDispatch" % classname, (dispatch_base,), {"__slots__": event_names}
+    )
+
+    dispatch_cls._event_names = event_names
+
+    dispatch_inst = cls._set_dispatch(cls, dispatch_cls)
+    for k in dispatch_cls._event_names:
+        setattr(dispatch_inst, k, _ClsLevelDispatch(cls, dict_[k]))
+        _registrars[k].append(cls)
+
+    for super_ in dispatch_cls.__bases__:
+        if issubclass(super_, _Dispatch) and super_ is not _Dispatch:
+            for ls in super_._events.dispatch._event_descriptors:
+                setattr(dispatch_inst, ls.name, ls)
+                dispatch_cls._event_names.append(ls.name)
+
+    if getattr(cls, "_dispatch_target", None):
+        the_cls = cls._dispatch_target
+        if (
+            hasattr(the_cls, "__slots__")
+            and "_slots_dispatch" in the_cls.__slots__
+        ):
+            cls._dispatch_target.dispatch = slots_dispatcher(cls)
+        else:
+            cls._dispatch_target.dispatch = dispatcher(cls)
+
+
+def _remove_dispatcher(cls):
+    for k in cls.dispatch._event_names:
+        _registrars[k].remove(cls)
+        if not _registrars[k]:
+            del _registrars[k]
+
+
+class Events(util.with_metaclass(_EventMeta, object)):
+    """Define event listening functions for a particular target type."""
+
+    @staticmethod
+    def _set_dispatch(cls, dispatch_cls):
+        # This allows an Events subclass to define additional utility
+        # methods made available to the target via
+        # "self.dispatch._events.<utilitymethod>"
+        # @staticmethod to allow easy "super" calls while in a metaclass
+        # constructor.
+        cls.dispatch = dispatch_cls(None)
+        dispatch_cls._events = cls
+        return cls.dispatch
+
+    @classmethod
+    def _accept_with(cls, target):
+        def dispatch_is(*types):
+            return all(isinstance(target.dispatch, t) for t in types)
+
+        def dispatch_parent_is(t):
+            return isinstance(target.dispatch.parent, t)
+
+        # Mapper, ClassManager, Session override this to
+        # also accept classes, scoped_sessions, sessionmakers, etc.
+        if hasattr(target, "dispatch"):
+            if (
+                dispatch_is(cls.dispatch.__class__)
+                or dispatch_is(type, cls.dispatch.__class__)
+                or (
+                    dispatch_is(_JoinedDispatcher)
+                    and dispatch_parent_is(cls.dispatch.__class__)
+                )
+            ):
+                return target
+
+    @classmethod
+    def _listen(
+        cls,
+        event_key,
+        propagate=False,
+        insert=False,
+        named=False,
+        asyncio=False,
+    ):
+        event_key.base_listen(
+            propagate=propagate, insert=insert, named=named, asyncio=asyncio
+        )
+
+    @classmethod
+    def _remove(cls, event_key):
+        event_key.remove()
+
+    @classmethod
+    def _clear(cls):
+        cls.dispatch._clear()
+
+
+class _JoinedDispatcher(object):
+    """Represent a connection between two _Dispatch objects."""
+
+    __slots__ = "local", "parent", "_instance_cls"
+
+    def __init__(self, local, parent):
+        self.local = local
+        self.parent = parent
+        self._instance_cls = self.local._instance_cls
+
+    def __getattr__(self, name):
+        # Assign _JoinedListeners as attributes on demand
+        # to reduce startup time for new dispatch objects.
+        ls = getattr(self.local, name)
+        jl = _JoinedListener(self.parent, ls.name, ls)
+        setattr(self, ls.name, jl)
+        return jl
+
+    @property
+    def _listen(self):
+        return self.parent._listen
+
+    @property
+    def _events(self):
+        return self.parent._events
+
+
+class dispatcher(object):
+    """Descriptor used by target classes to
+    deliver the _Dispatch class at the class level
+    and produce new _Dispatch instances for target
+    instances.
+
+    """
+
+    def __init__(self, events):
+        self.dispatch = events.dispatch
+        self.events = events
+
+    def __get__(self, obj, cls):
+        if obj is None:
+            return self.dispatch
+
+        disp = self.dispatch._for_instance(obj)
+        try:
+            obj.__dict__["dispatch"] = disp
+        except AttributeError as ae:
+            util.raise_(
+                TypeError(
+                    "target %r doesn't have __dict__, should it be "
+                    "defining _slots_dispatch?" % (obj,)
+                ),
+                replace_context=ae,
+            )
+        return disp
+
+
+class slots_dispatcher(dispatcher):
+    def __get__(self, obj, cls):
+        if obj is None:
+            return self.dispatch
+
+        if hasattr(obj, "_slots_dispatch"):
+            return obj._slots_dispatch
+
+        disp = self.dispatch._for_instance(obj)
+        obj._slots_dispatch = disp
+        return disp

lib/sqlalchemy/event/legacy.py

@@ -0,0 +1,185 @@
+# event/legacy.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""Routines to handle adaption of legacy call signatures,
+generation of deprecation notes and docstrings.
+
+"""
+
+from .. import util
+
+
+def _legacy_signature(since, argnames, converter=None):
+    def leg(fn):
+        if not hasattr(fn, "_legacy_signatures"):
+            fn._legacy_signatures = []
+        fn._legacy_signatures.append((since, argnames, converter))
+        return fn
+
+    return leg
+
+
+def _wrap_fn_for_legacy(dispatch_collection, fn, argspec):
+    for since, argnames, conv in dispatch_collection.legacy_signatures:
+        if argnames[-1] == "**kw":
+            has_kw = True
+            argnames = argnames[0:-1]
+        else:
+            has_kw = False
+
+        if len(argnames) == len(argspec.args) and has_kw is bool(
+            argspec.varkw
+        ):
+
+            formatted_def = "def %s(%s%s)" % (
+                dispatch_collection.name,
+                ", ".join(dispatch_collection.arg_names),
+                ", **kw" if has_kw else "",
+            )
+            warning_txt = (
+                'The argument signature for the "%s.%s" event listener '
+                "has changed as of version %s, and conversion for "
+                "the old argument signature will be removed in a "
+                'future release.  The new signature is "%s"'
+                % (
+                    dispatch_collection.clsname,
+                    dispatch_collection.name,
+                    since,
+                    formatted_def,
+                )
+            )
+
+            if conv:
+                assert not has_kw
+
+                def wrap_leg(*args):
+                    util.warn_deprecated(warning_txt, version=since)
+                    return fn(*conv(*args))
+
+            else:
+
+                def wrap_leg(*args, **kw):
+                    util.warn_deprecated(warning_txt, version=since)
+                    argdict = dict(zip(dispatch_collection.arg_names, args))
+                    args = [argdict[name] for name in argnames]
+                    if has_kw:
+                        return fn(*args, **kw)
+                    else:
+                        return fn(*args)
+
+            return wrap_leg
+    else:
+        return fn
+
+
+def _indent(text, indent):
+    return "\n".join(indent + line for line in text.split("\n"))
+
+
+def _standard_listen_example(dispatch_collection, sample_target, fn):
+    example_kw_arg = _indent(
+        "\n".join(
+            "%(arg)s = kw['%(arg)s']" % {"arg": arg}
+            for arg in dispatch_collection.arg_names[0:2]
+        ),
+        "    ",
+    )
+    if dispatch_collection.legacy_signatures:
+        current_since = max(
+            since
+            for since, args, conv in dispatch_collection.legacy_signatures
+        )
+    else:
+        current_since = None
+    text = (
+        "from sqlalchemy import event\n\n\n"
+        "@event.listens_for(%(sample_target)s, '%(event_name)s')\n"
+        "def receive_%(event_name)s("
+        "%(named_event_arguments)s%(has_kw_arguments)s):\n"
+        "    \"listen for the '%(event_name)s' event\"\n"
+        "\n    # ... (event handling logic) ...\n"
+    )
+
+    text %= {
+        "current_since": " (arguments as of %s)" % current_since
+        if current_since
+        else "",
+        "event_name": fn.__name__,
+        "has_kw_arguments": ", **kw" if dispatch_collection.has_kw else "",
+        "named_event_arguments": ", ".join(dispatch_collection.arg_names),
+        "example_kw_arg": example_kw_arg,
+        "sample_target": sample_target,
+    }
+    return text
+
+
+def _legacy_listen_examples(dispatch_collection, sample_target, fn):
+    text = ""
+    for since, args, conv in dispatch_collection.legacy_signatures:
+        text += (
+            "\n# DEPRECATED calling style (pre-%(since)s, "
+            "will be removed in a future release)\n"
+            "@event.listens_for(%(sample_target)s, '%(event_name)s')\n"
+            "def receive_%(event_name)s("
+            "%(named_event_arguments)s%(has_kw_arguments)s):\n"
+            "    \"listen for the '%(event_name)s' event\"\n"
+            "\n    # ... (event handling logic) ...\n"
+            % {
+                "since": since,
+                "event_name": fn.__name__,
+                "has_kw_arguments": " **kw"
+                if dispatch_collection.has_kw
+                else "",
+                "named_event_arguments": ", ".join(args),
+                "sample_target": sample_target,
+            }
+        )
+    return text
+
+
+def _version_signature_changes(parent_dispatch_cls, dispatch_collection):
+    since, args, conv = dispatch_collection.legacy_signatures[0]
+    return (
+        "\n.. deprecated:: %(since)s\n"
+        "    The :class:`.%(clsname)s.%(event_name)s` event now accepts the \n"
+        "    arguments ``%(named_event_arguments)s%(has_kw_arguments)s``.\n"
+        "    Support for listener functions which accept the previous \n"
+        '    argument signature(s) listed above as "deprecated" will be \n'
+        "    removed in a future release."
+        % {
+            "since": since,
+            "clsname": parent_dispatch_cls.__name__,
+            "event_name": dispatch_collection.name,
+            "named_event_arguments": ", ".join(dispatch_collection.arg_names),
+            "has_kw_arguments": ", **kw" if dispatch_collection.has_kw else "",
+        }
+    )
+
+
+def _augment_fn_docs(dispatch_collection, parent_dispatch_cls, fn):
+    header = (
+        ".. container:: event_signatures\n\n"
+        "     Example argument forms::\n"
+        "\n"
+    )
+
+    sample_target = getattr(parent_dispatch_cls, "_target_class_doc", "obj")
+    text = header + _indent(
+        _standard_listen_example(dispatch_collection, sample_target, fn),
+        " " * 8,
+    )
+    if dispatch_collection.legacy_signatures:
+        text += _indent(
+            _legacy_listen_examples(dispatch_collection, sample_target, fn),
+            " " * 8,
+        )
+
+        text += _version_signature_changes(
+            parent_dispatch_cls, dispatch_collection
+        )
+
+    return util.inject_docstring_text(fn.__doc__, text, 1)

lib/sqlalchemy/event/registry.py

@@ -0,0 +1,297 @@
+# event/registry.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""Provides managed registration services on behalf of :func:`.listen`
+arguments.
+
+By "managed registration", we mean that event listening functions and
+other objects can be added to various collections in such a way that their
+membership in all those collections can be revoked at once, based on
+an equivalent :class:`._EventKey`.
+
+"""
+
+from __future__ import absolute_import
+
+import collections
+import types
+import weakref
+
+from .. import exc
+from .. import util
+
+
+_key_to_collection = collections.defaultdict(dict)
+"""
+Given an original listen() argument, can locate all
+listener collections and the listener fn contained
+
+(target, identifier, fn) -> {
+                            ref(listenercollection) -> ref(listener_fn)
+                            ref(listenercollection) -> ref(listener_fn)
+                            ref(listenercollection) -> ref(listener_fn)
+                        }
+"""
+
+_collection_to_key = collections.defaultdict(dict)
+"""
+Given a _ListenerCollection or _ClsLevelListener, can locate
+all the original listen() arguments and the listener fn contained
+
+ref(listenercollection) -> {
+                            ref(listener_fn) -> (target, identifier, fn),
+                            ref(listener_fn) -> (target, identifier, fn),
+                            ref(listener_fn) -> (target, identifier, fn),
+                        }
+"""
+
+
+def _collection_gced(ref):
+    # defaultdict, so can't get a KeyError
+    if not _collection_to_key or ref not in _collection_to_key:
+        return
+    listener_to_key = _collection_to_key.pop(ref)
+    for key in listener_to_key.values():
+        if key in _key_to_collection:
+            # defaultdict, so can't get a KeyError
+            dispatch_reg = _key_to_collection[key]
+            dispatch_reg.pop(ref)
+            if not dispatch_reg:
+                _key_to_collection.pop(key)
+
+
+def _stored_in_collection(event_key, owner):
+    key = event_key._key
+
+    dispatch_reg = _key_to_collection[key]
+
+    owner_ref = owner.ref
+    listen_ref = weakref.ref(event_key._listen_fn)
+
+    if owner_ref in dispatch_reg:
+        return False
+
+    dispatch_reg[owner_ref] = listen_ref
+
+    listener_to_key = _collection_to_key[owner_ref]
+    listener_to_key[listen_ref] = key
+
+    return True
+
+
+def _removed_from_collection(event_key, owner):
+    key = event_key._key
+
+    dispatch_reg = _key_to_collection[key]
+
+    listen_ref = weakref.ref(event_key._listen_fn)
+
+    owner_ref = owner.ref
+    dispatch_reg.pop(owner_ref, None)
+    if not dispatch_reg:
+        del _key_to_collection[key]
+
+    if owner_ref in _collection_to_key:
+        listener_to_key = _collection_to_key[owner_ref]
+        listener_to_key.pop(listen_ref)
+
+
+def _stored_in_collection_multi(newowner, oldowner, elements):
+    if not elements:
+        return
+
+    oldowner = oldowner.ref
+    newowner = newowner.ref
+
+    old_listener_to_key = _collection_to_key[oldowner]
+    new_listener_to_key = _collection_to_key[newowner]
+
+    for listen_fn in elements:
+        listen_ref = weakref.ref(listen_fn)
+        try:
+            key = old_listener_to_key[listen_ref]
+        except KeyError:
+            # can occur during interpreter shutdown.
+            # see #6740
+            continue
+
+        try:
+            dispatch_reg = _key_to_collection[key]
+        except KeyError:
+            continue
+
+        if newowner in dispatch_reg:
+            assert dispatch_reg[newowner] == listen_ref
+        else:
+            dispatch_reg[newowner] = listen_ref
+
+        new_listener_to_key[listen_ref] = key
+
+
+def _clear(owner, elements):
+    if not elements:
+        return
+
+    owner = owner.ref
+    listener_to_key = _collection_to_key[owner]
+    for listen_fn in elements:
+        listen_ref = weakref.ref(listen_fn)
+        key = listener_to_key[listen_ref]
+        dispatch_reg = _key_to_collection[key]
+        dispatch_reg.pop(owner, None)
+
+        if not dispatch_reg:
+            del _key_to_collection[key]
+
+
+class _EventKey(object):
+    """Represent :func:`.listen` arguments."""
+
+    __slots__ = (
+        "target",
+        "identifier",
+        "fn",
+        "fn_key",
+        "fn_wrap",
+        "dispatch_target",
+    )
+
+    def __init__(self, target, identifier, fn, dispatch_target, _fn_wrap=None):
+        self.target = target
+        self.identifier = identifier
+        self.fn = fn
+        if isinstance(fn, types.MethodType):
+            self.fn_key = id(fn.__func__), id(fn.__self__)
+        else:
+            self.fn_key = id(fn)
+        self.fn_wrap = _fn_wrap
+        self.dispatch_target = dispatch_target
+
+    @property
+    def _key(self):
+        return (id(self.target), self.identifier, self.fn_key)
+
+    def with_wrapper(self, fn_wrap):
+        if fn_wrap is self._listen_fn:
+            return self
+        else:
+            return _EventKey(
+                self.target,
+                self.identifier,
+                self.fn,
+                self.dispatch_target,
+                _fn_wrap=fn_wrap,
+            )
+
+    def with_dispatch_target(self, dispatch_target):
+        if dispatch_target is self.dispatch_target:
+            return self
+        else:
+            return _EventKey(
+                self.target,
+                self.identifier,
+                self.fn,
+                dispatch_target,
+                _fn_wrap=self.fn_wrap,
+            )
+
+    def listen(self, *args, **kw):
+        once = kw.pop("once", False)
+        once_unless_exception = kw.pop("_once_unless_exception", False)
+        named = kw.pop("named", False)
+
+        target, identifier, fn = (
+            self.dispatch_target,
+            self.identifier,
+            self._listen_fn,
+        )
+
+        dispatch_collection = getattr(target.dispatch, identifier)
+
+        adjusted_fn = dispatch_collection._adjust_fn_spec(fn, named)
+
+        self = self.with_wrapper(adjusted_fn)
+
+        stub_function = getattr(
+            self.dispatch_target.dispatch._events, self.identifier
+        )
+        if hasattr(stub_function, "_sa_warn"):
+            stub_function._sa_warn()
+
+        if once or once_unless_exception:
+            self.with_wrapper(
+                util.only_once(
+                    self._listen_fn, retry_on_exception=once_unless_exception
+                )
+            ).listen(*args, **kw)
+        else:
+            self.dispatch_target.dispatch._listen(self, *args, **kw)
+
+    def remove(self):
+        key = self._key
+
+        if key not in _key_to_collection:
+            raise exc.InvalidRequestError(
+                "No listeners found for event %s / %r / %s "
+                % (self.target, self.identifier, self.fn)
+            )
+
+        dispatch_reg = _key_to_collection.pop(key)
+
+        for collection_ref, listener_ref in dispatch_reg.items():
+            collection = collection_ref()
+            listener_fn = listener_ref()
+            if collection is not None and listener_fn is not None:
+                collection.remove(self.with_wrapper(listener_fn))
+
+    def contains(self):
+        """Return True if this event key is registered to listen."""
+        return self._key in _key_to_collection
+
+    def base_listen(
+        self,
+        propagate=False,
+        insert=False,
+        named=False,
+        retval=None,
+        asyncio=False,
+    ):
+
+        target, identifier = self.dispatch_target, self.identifier
+
+        dispatch_collection = getattr(target.dispatch, identifier)
+
+        for_modify = dispatch_collection.for_modify(target.dispatch)
+        if asyncio:
+            for_modify._set_asyncio()
+
+        if insert:
+            for_modify.insert(self, propagate)
+        else:
+            for_modify.append(self, propagate)
+
+    @property
+    def _listen_fn(self):
+        return self.fn_wrap or self.fn
+
+    def append_to_list(self, owner, list_):
+        if _stored_in_collection(self, owner):
+            list_.append(self._listen_fn)
+            return True
+        else:
+            return False
+
+    def remove_from_list(self, owner, list_):
+        _removed_from_collection(self, owner)
+        list_.remove(self._listen_fn)
+
+    def prepend_to_list(self, owner, list_):
+        if _stored_in_collection(self, owner):
+            list_.appendleft(self._listen_fn)
+            return True
+        else:
+            return False

lib/sqlalchemy/events.py

@@ -0,0 +1,14 @@
+# sqlalchemy/events.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""Core event interfaces."""
+
+from .engine.events import ConnectionEvents
+from .engine.events import DialectEvents
+from .pool.events import PoolEvents
+from .sql.base import SchemaEventTarget
+from .sql.events import DDLEvents

lib/sqlalchemy/exc.py

@@ -0,0 +1,733 @@
+# sqlalchemy/exc.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""Exceptions used with SQLAlchemy.
+
+The base exception class is :exc:`.SQLAlchemyError`.  Exceptions which are
+raised as a result of DBAPI exceptions are all subclasses of
+:exc:`.DBAPIError`.
+
+"""
+
+from .util import _preloaded
+from .util import compat
+
+_version_token = None
+
+
+class HasDescriptionCode(object):
+    """helper which adds 'code' as an attribute and '_code_str' as a method"""
+
+    code = None
+
+    def __init__(self, *arg, **kw):
+        code = kw.pop("code", None)
+        if code is not None:
+            self.code = code
+        super(HasDescriptionCode, self).__init__(*arg, **kw)
+
+    def _code_str(self):
+        if not self.code:
+            return ""
+        else:
+            return (
+                "(Background on this error at: "
+                "https://sqlalche.me/e/%s/%s)"
+                % (
+                    _version_token,
+                    self.code,
+                )
+            )
+
+    def __str__(self):
+        message = super(HasDescriptionCode, self).__str__()
+        if self.code:
+            message = "%s %s" % (message, self._code_str())
+        return message
+
+
+class SQLAlchemyError(HasDescriptionCode, Exception):
+    """Generic error class."""
+
+    def _message(self, as_unicode=compat.py3k):
+        # rules:
+        #
+        # 1. under py2k, for __str__ return single string arg as it was
+        # given without converting to unicode.  for __unicode__
+        # do a conversion but check that it's not unicode already just in
+        # case
+        #
+        # 2. under py3k, single arg string will usually be a unicode
+        # object, but since __str__() must return unicode, check for
+        # bytestring just in case
+        #
+        # 3. for multiple self.args, this is not a case in current
+        # SQLAlchemy though this is happening in at least one known external
+        # library, call str() which does a repr().
+        #
+        if len(self.args) == 1:
+            text = self.args[0]
+
+            if as_unicode and isinstance(text, compat.binary_types):
+                text = compat.decode_backslashreplace(text, "utf-8")
+            # This is for when the argument is not a string of any sort.
+            # Otherwise, converting this exception to string would fail for
+            # non-string arguments.
+            elif compat.py3k or not as_unicode:
+                text = str(text)
+            else:
+                text = compat.text_type(text)
+
+            return text
+        else:
+            # this is not a normal case within SQLAlchemy but is here for
+            # compatibility with Exception.args - the str() comes out as
+            # a repr() of the tuple
+            return str(self.args)
+
+    def _sql_message(self, as_unicode):
+        message = self._message(as_unicode)
+
+        if self.code:
+            message = "%s %s" % (message, self._code_str())
+
+        return message
+
+    def __str__(self):
+        return self._sql_message(compat.py3k)
+
+    def __unicode__(self):
+        return self._sql_message(as_unicode=True)
+
+
+class ArgumentError(SQLAlchemyError):
+    """Raised when an invalid or conflicting function argument is supplied.
+
+    This error generally corresponds to construction time state errors.
+
+    """
+
+
+class ObjectNotExecutableError(ArgumentError):
+    """Raised when an object is passed to .execute() that can't be
+    executed as SQL.
+
+    .. versionadded:: 1.1
+
+    """
+
+    def __init__(self, target):
+        super(ObjectNotExecutableError, self).__init__(
+            "Not an executable object: %r" % target
+        )
+        self.target = target
+
+    def __reduce__(self):
+        return self.__class__, (self.target,)
+
+
+class NoSuchModuleError(ArgumentError):
+    """Raised when a dynamically-loaded module (usually a database dialect)
+    of a particular name cannot be located."""
+
+
+class NoForeignKeysError(ArgumentError):
+    """Raised when no foreign keys can be located between two selectables
+    during a join."""
+
+
+class AmbiguousForeignKeysError(ArgumentError):
+    """Raised when more than one foreign key matching can be located
+    between two selectables during a join."""
+
+
+class CircularDependencyError(SQLAlchemyError):
+    """Raised by topological sorts when a circular dependency is detected.
+
+    There are two scenarios where this error occurs:
+
+    * In a Session flush operation, if two objects are mutually dependent
+      on each other, they can not be inserted or deleted via INSERT or
+      DELETE statements alone; an UPDATE will be needed to post-associate
+      or pre-deassociate one of the foreign key constrained values.
+      The ``post_update`` flag described at :ref:`post_update` can resolve
+      this cycle.
+    * In a :attr:`_schema.MetaData.sorted_tables` operation, two
+      :class:`_schema.ForeignKey`
+      or :class:`_schema.ForeignKeyConstraint` objects mutually refer to each
+      other.  Apply the ``use_alter=True`` flag to one or both,
+      see :ref:`use_alter`.
+
+    """
+
+    def __init__(self, message, cycles, edges, msg=None, code=None):
+        if msg is None:
+            message += " (%s)" % ", ".join(repr(s) for s in cycles)
+        else:
+            message = msg
+        SQLAlchemyError.__init__(self, message, code=code)
+        self.cycles = cycles
+        self.edges = edges
+
+    def __reduce__(self):
+        return (
+            self.__class__,
+            (None, self.cycles, self.edges, self.args[0]),
+            {"code": self.code} if self.code is not None else {},
+        )
+
+
+class CompileError(SQLAlchemyError):
+    """Raised when an error occurs during SQL compilation"""
+
+
+class UnsupportedCompilationError(CompileError):
+    """Raised when an operation is not supported by the given compiler.
+
+    .. seealso::
+
+        :ref:`faq_sql_expression_string`
+
+        :ref:`error_l7de`
+    """
+
+    code = "l7de"
+
+    def __init__(self, compiler, element_type, message=None):
+        super(UnsupportedCompilationError, self).__init__(
+            "Compiler %r can't render element of type %s%s"
+            % (compiler, element_type, ": %s" % message if message else "")
+        )
+        self.compiler = compiler
+        self.element_type = element_type
+        self.message = message
+
+    def __reduce__(self):
+        return self.__class__, (self.compiler, self.element_type, self.message)
+
+
+class IdentifierError(SQLAlchemyError):
+    """Raised when a schema name is beyond the max character limit"""
+
+
+class DisconnectionError(SQLAlchemyError):
+    """A disconnect is detected on a raw DB-API connection.
+
+    This error is raised and consumed internally by a connection pool.  It can
+    be raised by the :meth:`_events.PoolEvents.checkout`
+    event so that the host pool
+    forces a retry; the exception will be caught three times in a row before
+    the pool gives up and raises :class:`~sqlalchemy.exc.InvalidRequestError`
+    regarding the connection attempt.
+
+    """
+
+    invalidate_pool = False
+
+
+class InvalidatePoolError(DisconnectionError):
+    """Raised when the connection pool should invalidate all stale connections.
+
+    A subclass of :class:`_exc.DisconnectionError` that indicates that the
+    disconnect situation encountered on the connection probably means the
+    entire pool should be invalidated, as the database has been restarted.
+
+    This exception will be handled otherwise the same way as
+    :class:`_exc.DisconnectionError`, allowing three attempts to reconnect
+    before giving up.
+
+    .. versionadded:: 1.2
+
+    """
+
+    invalidate_pool = True
+
+
+class TimeoutError(SQLAlchemyError):  # noqa
+    """Raised when a connection pool times out on getting a connection."""
+
+
+class InvalidRequestError(SQLAlchemyError):
+    """SQLAlchemy was asked to do something it can't do.
+
+    This error generally corresponds to runtime state errors.
+
+    """
+
+
+class NoInspectionAvailable(InvalidRequestError):
+    """A subject passed to :func:`sqlalchemy.inspection.inspect` produced
+    no context for inspection."""
+
+
+class PendingRollbackError(InvalidRequestError):
+    """A transaction has failed and needs to be rolled back before
+    continuing.
+
+    .. versionadded:: 1.4
+
+    """
+
+
+class ResourceClosedError(InvalidRequestError):
+    """An operation was requested from a connection, cursor, or other
+    object that's in a closed state."""
+
+
+class NoSuchColumnError(InvalidRequestError, KeyError):
+    """A nonexistent column is requested from a ``Row``."""
+
+
+class NoResultFound(InvalidRequestError):
+    """A database result was required but none was found.
+
+
+    .. versionchanged:: 1.4  This exception is now part of the
+       ``sqlalchemy.exc`` module in Core, moved from the ORM.  The symbol
+       remains importable from ``sqlalchemy.orm.exc``.
+
+
+    """
+
+
+class MultipleResultsFound(InvalidRequestError):
+    """A single database result was required but more than one were found.
+
+    .. versionchanged:: 1.4  This exception is now part of the
+       ``sqlalchemy.exc`` module in Core, moved from the ORM.  The symbol
+       remains importable from ``sqlalchemy.orm.exc``.
+
+
+    """
+
+
+class NoReferenceError(InvalidRequestError):
+    """Raised by ``ForeignKey`` to indicate a reference cannot be resolved."""
+
+
+class AwaitRequired(InvalidRequestError):
+    """Error raised by the async greenlet spawn if no async operation
+    was awaited when it required one.
+
+    """
+
+    code = "xd1r"
+
+
+class MissingGreenlet(InvalidRequestError):
+    r"""Error raised by the async greenlet await\_ if called while not inside
+    the greenlet spawn context.
+
+    """
+
+    code = "xd2s"
+
+
+class NoReferencedTableError(NoReferenceError):
+    """Raised by ``ForeignKey`` when the referred ``Table`` cannot be
+    located.
+
+    """
+
+    def __init__(self, message, tname):
+        NoReferenceError.__init__(self, message)
+        self.table_name = tname
+
+    def __reduce__(self):
+        return self.__class__, (self.args[0], self.table_name)
+
+
+class NoReferencedColumnError(NoReferenceError):
+    """Raised by ``ForeignKey`` when the referred ``Column`` cannot be
+    located.
+
+    """
+
+    def __init__(self, message, tname, cname):
+        NoReferenceError.__init__(self, message)
+        self.table_name = tname
+        self.column_name = cname
+
+    def __reduce__(self):
+        return (
+            self.__class__,
+            (self.args[0], self.table_name, self.column_name),
+        )
+
+
+class NoSuchTableError(InvalidRequestError):
+    """Table does not exist or is not visible to a connection."""
+
+
+class UnreflectableTableError(InvalidRequestError):
+    """Table exists but can't be reflected for some reason.
+
+    .. versionadded:: 1.2
+
+    """
+
+
+class UnboundExecutionError(InvalidRequestError):
+    """SQL was attempted without a database connection to execute it on."""
+
+
+class DontWrapMixin(object):
+    """A mixin class which, when applied to a user-defined Exception class,
+    will not be wrapped inside of :exc:`.StatementError` if the error is
+    emitted within the process of executing a statement.
+
+    E.g.::
+
+        from sqlalchemy.exc import DontWrapMixin
+
+        class MyCustomException(Exception, DontWrapMixin):
+            pass
+
+        class MySpecialType(TypeDecorator):
+            impl = String
+
+            def process_bind_param(self, value, dialect):
+                if value == 'invalid':
+                    raise MyCustomException("invalid!")
+
+    """
+
+
+class StatementError(SQLAlchemyError):
+    """An error occurred during execution of a SQL statement.
+
+    :class:`StatementError` wraps the exception raised
+    during execution, and features :attr:`.statement`
+    and :attr:`.params` attributes which supply context regarding
+    the specifics of the statement which had an issue.
+
+    The wrapped exception object is available in
+    the :attr:`.orig` attribute.
+
+    """
+
+    statement = None
+    """The string SQL statement being invoked when this exception occurred."""
+
+    params = None
+    """The parameter list being used when this exception occurred."""
+
+    orig = None
+    """The DBAPI exception object."""
+
+    ismulti = None
+
+    def __init__(
+        self,
+        message,
+        statement,
+        params,
+        orig,
+        hide_parameters=False,
+        code=None,
+        ismulti=None,
+    ):
+        SQLAlchemyError.__init__(self, message, code=code)
+        self.statement = statement
+        self.params = params
+        self.orig = orig
+        self.ismulti = ismulti
+        self.hide_parameters = hide_parameters
+        self.detail = []
+
+    def add_detail(self, msg):
+        self.detail.append(msg)
+
+    def __reduce__(self):
+        return (
+            self.__class__,
+            (
+                self.args[0],
+                self.statement,
+                self.params,
+                self.orig,
+                self.hide_parameters,
+                self.__dict__.get("code"),
+                self.ismulti,
+            ),
+            {"detail": self.detail},
+        )
+
+    @_preloaded.preload_module("sqlalchemy.sql.util")
+    def _sql_message(self, as_unicode):
+        util = _preloaded.preloaded.sql_util
+
+        details = [self._message(as_unicode=as_unicode)]
+        if self.statement:
+            if not as_unicode and not compat.py3k:
+                stmt_detail = "[SQL: %s]" % compat.safe_bytestring(
+                    self.statement
+                )
+            else:
+                stmt_detail = "[SQL: %s]" % self.statement
+            details.append(stmt_detail)
+            if self.params:
+                if self.hide_parameters:
+                    details.append(
+                        "[SQL parameters hidden due to hide_parameters=True]"
+                    )
+                else:
+                    params_repr = util._repr_params(
+                        self.params, 10, ismulti=self.ismulti
+                    )
+                    details.append("[parameters: %r]" % params_repr)
+        code_str = self._code_str()
+        if code_str:
+            details.append(code_str)
+        return "\n".join(["(%s)" % det for det in self.detail] + details)
+
+
+class DBAPIError(StatementError):
+    """Raised when the execution of a database operation fails.
+
+    Wraps exceptions raised by the DB-API underlying the
+    database operation.  Driver-specific implementations of the standard
+    DB-API exception types are wrapped by matching sub-types of SQLAlchemy's
+    :class:`DBAPIError` when possible.  DB-API's ``Error`` type maps to
+    :class:`DBAPIError` in SQLAlchemy, otherwise the names are identical.  Note
+    that there is no guarantee that different DB-API implementations will
+    raise the same exception type for any given error condition.
+
+    :class:`DBAPIError` features :attr:`~.StatementError.statement`
+    and :attr:`~.StatementError.params` attributes which supply context
+    regarding the specifics of the statement which had an issue, for the
+    typical case when the error was raised within the context of
+    emitting a SQL statement.
+
+    The wrapped exception object is available in the
+    :attr:`~.StatementError.orig` attribute. Its type and properties are
+    DB-API implementation specific.
+
+    """
+
+    code = "dbapi"
+
+    @classmethod
+    def instance(
+        cls,
+        statement,
+        params,
+        orig,
+        dbapi_base_err,
+        hide_parameters=False,
+        connection_invalidated=False,
+        dialect=None,
+        ismulti=None,
+    ):
+        # Don't ever wrap these, just return them directly as if
+        # DBAPIError didn't exist.
+        if (
+            isinstance(orig, BaseException) and not isinstance(orig, Exception)
+        ) or isinstance(orig, DontWrapMixin):
+            return orig
+
+        if orig is not None:
+            # not a DBAPI error, statement is present.
+            # raise a StatementError
+            if isinstance(orig, SQLAlchemyError) and statement:
+                return StatementError(
+                    "(%s.%s) %s"
+                    % (
+                        orig.__class__.__module__,
+                        orig.__class__.__name__,
+                        orig.args[0],
+                    ),
+                    statement,
+                    params,
+                    orig,
+                    hide_parameters=hide_parameters,
+                    code=orig.code,
+                    ismulti=ismulti,
+                )
+            elif not isinstance(orig, dbapi_base_err) and statement:
+                return StatementError(
+                    "(%s.%s) %s"
+                    % (
+                        orig.__class__.__module__,
+                        orig.__class__.__name__,
+                        orig,
+                    ),
+                    statement,
+                    params,
+                    orig,
+                    hide_parameters=hide_parameters,
+                    ismulti=ismulti,
+                )
+
+            glob = globals()
+            for super_ in orig.__class__.__mro__:
+                name = super_.__name__
+                if dialect:
+                    name = dialect.dbapi_exception_translation_map.get(
+                        name, name
+                    )
+                if name in glob and issubclass(glob[name], DBAPIError):
+                    cls = glob[name]
+                    break
+
+        return cls(
+            statement,
+            params,
+            orig,
+            connection_invalidated=connection_invalidated,
+            hide_parameters=hide_parameters,
+            code=cls.code,
+            ismulti=ismulti,
+        )
+
+    def __reduce__(self):
+        return (
+            self.__class__,
+            (
+                self.statement,
+                self.params,
+                self.orig,
+                self.hide_parameters,
+                self.connection_invalidated,
+                self.__dict__.get("code"),
+                self.ismulti,
+            ),
+            {"detail": self.detail},
+        )
+
+    def __init__(
+        self,
+        statement,
+        params,
+        orig,
+        hide_parameters=False,
+        connection_invalidated=False,
+        code=None,
+        ismulti=None,
+    ):
+        try:
+            text = str(orig)
+        except Exception as e:
+            text = "Error in str() of DB-API-generated exception: " + str(e)
+        StatementError.__init__(
+            self,
+            "(%s.%s) %s"
+            % (orig.__class__.__module__, orig.__class__.__name__, text),
+            statement,
+            params,
+            orig,
+            hide_parameters,
+            code=code,
+            ismulti=ismulti,
+        )
+        self.connection_invalidated = connection_invalidated
+
+
+class InterfaceError(DBAPIError):
+    """Wraps a DB-API InterfaceError."""
+
+    code = "rvf5"
+
+
+class DatabaseError(DBAPIError):
+    """Wraps a DB-API DatabaseError."""
+
+    code = "4xp6"
+
+
+class DataError(DatabaseError):
+    """Wraps a DB-API DataError."""
+
+    code = "9h9h"
+
+
+class OperationalError(DatabaseError):
+    """Wraps a DB-API OperationalError."""
+
+    code = "e3q8"
+
+
+class IntegrityError(DatabaseError):
+    """Wraps a DB-API IntegrityError."""
+
+    code = "gkpj"
+
+
+class InternalError(DatabaseError):
+    """Wraps a DB-API InternalError."""
+
+    code = "2j85"
+
+
+class ProgrammingError(DatabaseError):
+    """Wraps a DB-API ProgrammingError."""
+
+    code = "f405"
+
+
+class NotSupportedError(DatabaseError):
+    """Wraps a DB-API NotSupportedError."""
+
+    code = "tw8g"
+
+
+# Warnings
+
+
+class SADeprecationWarning(HasDescriptionCode, DeprecationWarning):
+    """Issued for usage of deprecated APIs."""
+
+    deprecated_since = None
+    "Indicates the version that started raising this deprecation warning"
+
+
+class Base20DeprecationWarning(SADeprecationWarning):
+    """Issued for usage of APIs specifically deprecated or legacy in
+    SQLAlchemy 2.0.
+
+    .. seealso::
+
+        :ref:`error_b8d9`.
+
+        :ref:`deprecation_20_mode`
+
+    """
+
+    deprecated_since = "1.4"
+    "Indicates the version that started raising this deprecation warning"
+
+    def __str__(self):
+        return (
+            super(Base20DeprecationWarning, self).__str__()
+            + " (Background on SQLAlchemy 2.0 at: https://sqlalche.me/e/b8d9)"
+        )
+
+
+class LegacyAPIWarning(Base20DeprecationWarning):
+    """indicates an API that is in 'legacy' status, a long term deprecation."""
+
+
+class RemovedIn20Warning(Base20DeprecationWarning):
+    """indicates an API that will be fully removed in SQLAlchemy 2.0."""
+
+
+class MovedIn20Warning(RemovedIn20Warning):
+    """Subtype of RemovedIn20Warning to indicate an API that moved only."""
+
+
+class SAPendingDeprecationWarning(PendingDeprecationWarning):
+    """A similar warning as :class:`_exc.SADeprecationWarning`, this warning
+    is not used in modern versions of SQLAlchemy.
+
+    """
+
+    deprecated_since = None
+    "Indicates the version that started raising this deprecation warning"
+
+
+class SAWarning(HasDescriptionCode, RuntimeWarning):
+    """Issued at runtime."""

lib/sqlalchemy/ext/__init__.py

@@ -0,0 +1,11 @@
+# ext/__init__.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from .. import util as _sa_util
+
+
+_sa_util.preloaded.import_prefix("sqlalchemy.ext")

lib/sqlalchemy/ext/asyncio/__init__.py

@@ -0,0 +1,22 @@
+# ext/asyncio/__init__.py
+# Copyright (C) 2020-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from .engine import async_engine_from_config
+from .engine import AsyncConnection
+from .engine import AsyncEngine
+from .engine import AsyncTransaction
+from .engine import create_async_engine
+from .events import AsyncConnectionEvents
+from .events import AsyncSessionEvents
+from .result import AsyncMappingResult
+from .result import AsyncResult
+from .result import AsyncScalarResult
+from .scoping import async_scoped_session
+from .session import async_object_session
+from .session import async_session
+from .session import AsyncSession
+from .session import AsyncSessionTransaction

lib/sqlalchemy/ext/asyncio/base.py

@@ -0,0 +1,89 @@
+import abc
+import functools
+import weakref
+
+from . import exc as async_exc
+
+
+class ReversibleProxy:
+    # weakref.ref(async proxy object) -> weakref.ref(sync proxied object)
+    _proxy_objects = {}
+    __slots__ = ("__weakref__",)
+
+    def _assign_proxied(self, target):
+        if target is not None:
+            target_ref = weakref.ref(target, ReversibleProxy._target_gced)
+            proxy_ref = weakref.ref(
+                self,
+                functools.partial(ReversibleProxy._target_gced, target_ref),
+            )
+            ReversibleProxy._proxy_objects[target_ref] = proxy_ref
+
+        return target
+
+    @classmethod
+    def _target_gced(cls, ref, proxy_ref=None):
+        cls._proxy_objects.pop(ref, None)
+
+    @classmethod
+    def _regenerate_proxy_for_target(cls, target):
+        raise NotImplementedError()
+
+    @classmethod
+    def _retrieve_proxy_for_target(cls, target, regenerate=True):
+        try:
+            proxy_ref = cls._proxy_objects[weakref.ref(target)]
+        except KeyError:
+            pass
+        else:
+            proxy = proxy_ref()
+            if proxy is not None:
+                return proxy
+
+        if regenerate:
+            return cls._regenerate_proxy_for_target(target)
+        else:
+            return None
+
+
+class StartableContext(abc.ABC):
+    __slots__ = ()
+
+    @abc.abstractmethod
+    async def start(self, is_ctxmanager=False):
+        pass
+
+    def __await__(self):
+        return self.start().__await__()
+
+    async def __aenter__(self):
+        return await self.start(is_ctxmanager=True)
+
+    @abc.abstractmethod
+    async def __aexit__(self, type_, value, traceback):
+        pass
+
+    def _raise_for_not_started(self):
+        raise async_exc.AsyncContextNotStarted(
+            "%s context has not been started and object has not been awaited."
+            % (self.__class__.__name__)
+        )
+
+
+class ProxyComparable(ReversibleProxy):
+    __slots__ = ()
+
+    def __hash__(self):
+        return id(self)
+
+    def __eq__(self, other):
+        return (
+            isinstance(other, self.__class__)
+            and self._proxied == other._proxied
+        )
+
+    def __ne__(self, other):
+        return (
+            not isinstance(other, self.__class__)
+            or self._proxied != other._proxied
+        )