Prevent merging of zero-value net.IP fields

- Fixes: #1710

Signed-off-by: Jonathon Anderson <janderson@ciq.com>

CHANGELOG.md

@@ -36,6 +36,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Create site overlay directory. #1690
 - Set execute permissions for intermediate directories during `wwctl overlay import --parents`. #1655
 - Fix log output formatting during overlay build.
+- Prevent merging of zero-value net.IP fields. #1710
 
 ## v4.6.0rc1, 2025-01-29
 

internal/pkg/node/mergo.go

@@ -71,7 +71,7 @@ type Transformer struct{}
 func (t Transformer) Transformer(typ reflect.Type) func(dst, src reflect.Value) error {
 	if typ == reflect.TypeOf(net.IP{}) {
 		return func(dst, src reflect.Value) error {
-			if !src.IsValid() || !src.CanSet() {
+			if !src.IsValid() || src.IsZero() {
 				return nil
 			}
 			dst.Set(src)

internal/pkg/node/mergo_test.go

@@ -935,11 +935,14 @@ nodeprofiles:
 nodes:
   n1:
     profiles:
-    - p1`,
-			node:   "n1",
-			field:  "NetDevs[default].Netmask",
-			source: "p1",
-			value:  "255.255.255.0",
+    - p1
+    network devices:
+      default:
+        ipaddr: 192.168.1.1`,
+			nodes:   []string{"n1", "n1"},
+			fields:  []string{"NetDevs[default].Netmask", "NetDevs[default].Ipaddr"},
+			sources: []string{"p1", ""},
+			values:  []string{"255.255.255.0", "192.168.1.1"},
 		},
 	}