initialize the map

pkg/controllers/workgenerator/controller.go

@@ -619,6 +619,9 @@ func (r *Reconciler) getConfigMapEnvelopWorkObj(ctx context.Context, workNamePre
 	}
 	work := workList.Items[0]
 	work.Labels[fleetv1beta1.ParentResourceSnapshotIndexLabel] = resourceSnapshot.Labels[fleetv1beta1.ResourceIndexLabel]
+	if work.Annotations == nil {
+		work.Annotations = make(map[string]string)
+	}
 	work.Annotations[fleetv1beta1.ParentResourceSnapshotNameAnnotation] = resourceBinding.Spec.ResourceSnapshotName
 	work.Annotations[fleetv1beta1.ParentResourceOverrideSnapshotHashAnnotation] = resourceOverrideSnapshotHash
 	work.Annotations[fleetv1beta1.ParentClusterResourceOverrideSnapshotHashAnnotation] = clusterResourceOverrideSnapshotHash
@@ -687,17 +690,20 @@ func (r *Reconciler) upsertWork(ctx context.Context, newWork, existingWork *flee
 	// we already checked the label in fetchAllResourceSnapShots function so no need to check again
 	resourceIndex, _ := labels.ExtractResourceIndexFromClusterResourceSnapshot(resourceSnapshot)
 	if workResourceIndex == resourceIndex {
-		// no need to do anything if the work is generated from the same snapshots
+		// no need to do anything if the work is generated from the same resource/override snapshots
 		if existingWork.Annotations[fleetv1beta1.ParentResourceOverrideSnapshotHashAnnotation] == newWork.Annotations[fleetv1beta1.ParentResourceOverrideSnapshotHashAnnotation] &&
 			existingWork.Annotations[fleetv1beta1.ParentClusterResourceOverrideSnapshotHashAnnotation] == newWork.Annotations[fleetv1beta1.ParentClusterResourceOverrideSnapshotHashAnnotation] {
-			klog.V(2).InfoS("Work is not associated with the desired override snapshots", "existingROHash", existingWork.Annotations[fleetv1beta1.ParentResourceOverrideSnapshotHashAnnotation],
+			klog.V(2).InfoS("Work is associated with the desired override snapshots", "existingROHash", existingWork.Annotations[fleetv1beta1.ParentResourceOverrideSnapshotHashAnnotation],
 				"existingCROHash", existingWork.Annotations[fleetv1beta1.ParentClusterResourceOverrideSnapshotHashAnnotation], "work", workObj)
 			return false, nil
 		}
 		klog.V(2).InfoS("Work is already associated with the desired resourceSnapshot but still not having the right override snapshots", "resourceIndex", resourceIndex, "work", workObj, "resourceSnapshot", resourceSnapshotObj)
 	}
 	// need to copy the new work to the existing work, only 5 possible changes:
 	existingWork.Labels[fleetv1beta1.ParentResourceSnapshotIndexLabel] = newWork.Labels[fleetv1beta1.ParentResourceSnapshotIndexLabel]
+	if existingWork.Annotations == nil {
+		existingWork.Annotations = make(map[string]string)
+	}
 	existingWork.Annotations[fleetv1beta1.ParentResourceSnapshotNameAnnotation] = newWork.Annotations[fleetv1beta1.ParentResourceSnapshotNameAnnotation]
 	existingWork.Annotations[fleetv1beta1.ParentResourceOverrideSnapshotHashAnnotation] = newWork.Annotations[fleetv1beta1.ParentResourceOverrideSnapshotHashAnnotation]
 	existingWork.Annotations[fleetv1beta1.ParentClusterResourceOverrideSnapshotHashAnnotation] = newWork.Annotations[fleetv1beta1.ParentClusterResourceOverrideSnapshotHashAnnotation]