Do not bypass same version unstructed conversion if it is a list

This give the converter a chance to convert list items to the requested version.

Author: mbohlool

staging/src/k8s.io/apimachinery/pkg/runtime/serializer/versioning/versioning.go

@@ -19,6 +19,7 @@ package versioning
 import (
 	"io"
 
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 )
@@ -170,17 +171,22 @@ func (c *codec) Encode(obj runtime.Object, w io.Writer) error {
 	case *runtime.Unknown:
 		return c.encoder.Encode(obj, w)
 	case runtime.Unstructured:
-		// avoid conversion roundtrip if GVK is the right one already or is empty (yes, this is a hack, but the old behaviour we rely on in kubectl)
-		objGVK := obj.GetObjectKind().GroupVersionKind()
-		if len(objGVK.Version) == 0 {
-			return c.encoder.Encode(obj, w)
-		}
-		targetGVK, ok := c.encodeVersion.KindForGroupVersionKinds([]schema.GroupVersionKind{objGVK})
-		if !ok {
-			return runtime.NewNotRegisteredGVKErrForTarget(objGVK, c.encodeVersion)
-		}
-		if targetGVK == objGVK {
-			return c.encoder.Encode(obj, w)
+		// An unstructured list can contain objects of multiple group version kinds. don't short-circuit just
+		// because the top-level type matches our desired destination type. actually send the object to the converter
+		// to give it a chance to convert the list items if needed.
+		if _, ok := obj.(*unstructured.UnstructuredList); !ok {
+			// avoid conversion roundtrip if GVK is the right one already or is empty (yes, this is a hack, but the old behaviour we rely on in kubectl)
+			objGVK := obj.GetObjectKind().GroupVersionKind()
+			if len(objGVK.Version) == 0 {
+				return c.encoder.Encode(obj, w)
+			}
+			targetGVK, ok := c.encodeVersion.KindForGroupVersionKinds([]schema.GroupVersionKind{objGVK})
+			if !ok {
+				return runtime.NewNotRegisteredGVKErrForTarget(objGVK, c.encodeVersion)
+			}
+			if targetGVK == objGVK {
+				return c.encoder.Encode(obj, w)
+			}
 		}
 	}