GC: Add check for nil interface

pkg/registry/rbac/helpers.go

@@ -17,6 +17,8 @@ limitations under the License.
 package rbac
 
 import (
+	"reflect"
+
 	"k8s.io/apimachinery/pkg/api/meta"
 	"k8s.io/apimachinery/pkg/conversion"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -25,6 +27,10 @@ import (
 // IsOnlyMutatingGCFields checks finalizers and ownerrefs which GC manipulates
 // and indicates that only those fields are changing
 func IsOnlyMutatingGCFields(obj, old runtime.Object, equalities conversion.Equalities) bool {
+	if old == nil || reflect.ValueOf(old).IsNil() {
+		return false
+	}
+
 	// make a copy of the newObj so that we can stomp for comparison
 	copied := obj.DeepCopyObject()
 	copiedMeta, err := meta.Accessor(copied)

pkg/registry/rbac/helpers_test.go

@@ -128,6 +128,19 @@ func TestIsOnlyMutatingGCFields(t *testing.T) {
 			},
 			expected: false,
 		},
+		{
+			name: "and nil",
+			obj: func() runtime.Object {
+				obj := newPod()
+				obj.OwnerReferences = append(obj.OwnerReferences, metav1.OwnerReference{Name: "foo"})
+				obj.Spec.RestartPolicy = kapi.RestartPolicyAlways
+				return obj
+			},
+			old: func() runtime.Object {
+				return (*kapi.Pod)(nil)
+			},
+			expected: false,
+		},
 	}
 
 	for _, tc := range tests {