Avoid accidental mutations during sanitize (#213)

The object passed to the sanitize method is now a copy.

Signed-off-by: Scott Andrews <andrewssc@vmware.com>

reconcilers/reconcilers.go

@@ -917,6 +917,10 @@ func (r *ChildReconciler) sanitize(child client.Object) interface{} {
 	if child == nil {
 		return nil
 	}
+
+	// avoid accidental mutations in Sanitize method
+	child = child.DeepCopyObject().(client.Object)
+
 	fn := reflect.ValueOf(r.Sanitize)
 	out := fn.Call([]reflect.Value{
 		reflect.ValueOf(child),

reconcilers/reconcilers_test.go

@@ -794,6 +794,36 @@ func TestChildReconciler(t *testing.T) {
 		ExpectCreates: []client.Object{
 			configMapCreate,
 		},
+	}, {
+		Name: "sanitize is mutation safe",
+		Parent: resource.
+			SpecDie(func(d *dies.TestResourceSpecDie) {
+				d.AddField("foo", "bar")
+			}),
+		Metadata: map[string]interface{}{
+			"SubReconciler": func(t *testing.T, c reconcilers.Config) reconcilers.SubReconciler {
+				r := defaultChildReconciler(c)
+				r.Sanitize = func(child *corev1.ConfigMap) interface{} {
+					child.Data["ignore"] = "me"
+					return child
+				}
+				return r
+			},
+		},
+		ExpectEvents: []rtesting.Event{
+			rtesting.NewEvent(resource, scheme, corev1.EventTypeNormal, "Created",
+				`Created ConfigMap %q`, testName),
+		},
+		ExpectParent: resourceReady.
+			SpecDie(func(d *dies.TestResourceSpecDie) {
+				d.AddField("foo", "bar")
+			}).
+			StatusDie(func(d *dies.TestResourceStatusDie) {
+				d.AddField("foo", "bar")
+			}),
+		ExpectCreates: []client.Object{
+			configMapCreate,
+		},
 	}, {
 		Name:   "error listing children",
 		Parent: resourceReady,