detector: eliminate the mutation of the informer cache

Signed-off-by: zhzhuang-zju <[email protected]>

Author: zhzhuang-zju

pkg/detector/detector.go

@@ -657,9 +657,6 @@ func (d *ResourceDetector) ApplyClusterPolicy(object *unstructured.Unstructured,
 }
 
 // GetUnstructuredObject retrieves object by key and returned its unstructured.
-// Any updates to this resource template are not recommended as it may come from the informer cache.
-// We should abide by the principle of making a deep copy first and then modifying it.
-// See issue: https://github.com/karmada-io/karmada/issues/3878.
 func (d *ResourceDetector) GetUnstructuredObject(objectKey keys.ClusterWideKey) (*unstructured.Unstructured, error) {
 	objectGVR, err := restmapper.GetGroupVersionResource(d.RESTMapper, objectKey.GroupVersionKind())
 	if err != nil {
@@ -689,7 +686,8 @@ func (d *ResourceDetector) GetUnstructuredObject(objectKey keys.ClusterWideKey)
 		return nil, err
 	}
 
-	return unstructuredObj, nil
+	// perform a deep copy to avoid modifying the cached object from informer
+	return unstructuredObj.DeepCopy(), nil
 }
 
 // ClaimPolicyForObject set policy identifier which the object associated with.

pkg/detector/policy.go

@@ -270,7 +270,6 @@ func (d *ResourceDetector) removeResourceClaimMetadataIfNotMatched(objectReferen
 		return false, nil
 	}
 
-	object = object.DeepCopy()
 	util.RemoveLabels(object, labels...)
 	util.RemoveAnnotations(object, annotations...)
 

pkg/util/helper/binding.go

@@ -238,9 +238,6 @@ func RemoveOrphanWorks(ctx context.Context, c client.Client, works []workv1alpha
 }
 
 // FetchResourceTemplate fetches the resource template to be propagated.
-// Any updates to this resource template are not recommended as it may come from the informer cache.
-// We should abide by the principle of making a deep copy first and then modifying it.
-// See issue: https://github.com/karmada-io/karmada/issues/3878.
 func FetchResourceTemplate(
 	ctx context.Context,
 	dynamicClient dynamic.Interface,
@@ -266,12 +263,13 @@ func FetchResourceTemplate(
 		// fall back to call api server in case the cache has not been synchronized yet
 		klog.Warningf("Failed to get resource template (%s/%s/%s) from cache, Error: %v. Fall back to call api server.",
 			resource.Kind, resource.Namespace, resource.Name, err)
-		object, err = dynamicClient.Resource(gvr).Namespace(resource.Namespace).Get(ctx, resource.Name, metav1.GetOptions{})
+		objectFromAPIServer, err := dynamicClient.Resource(gvr).Namespace(resource.Namespace).Get(ctx, resource.Name, metav1.GetOptions{})
 		if err != nil {
 			klog.Errorf("Failed to get resource template (%s/%s/%s) from api server, Error: %v",
 				resource.Kind, resource.Namespace, resource.Name, err)
 			return nil, err
 		}
+		return objectFromAPIServer, nil
 	}
 
 	unstructuredObj, err := ToUnstructured(object)
@@ -280,7 +278,7 @@ func FetchResourceTemplate(
 		return nil, err
 	}
 
-	return unstructuredObj, nil
+	return unstructuredObj.DeepCopy(), nil
 }
 
 // FetchResourceTemplatesByLabelSelector fetches the resource templates by label selector to be propagated.