Skip DeleteSnapshot when ProviderSnapshotID is empty (#9795)

When CreateSnapshot fails (e.g. quota limit), the snapshot is recorded
with an empty ProviderSnapshotID. During backup deletion, velero was
calling DeleteSnapshot("") which produces unnecessary 404 API calls.

Skip the DeleteSnapshot call when ProviderSnapshotID is empty and log
a warning instead.

Fixes #9429

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Signed-off-by: Tiger Kaovilai <tkaovila@redhat.com>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Happy <yesreply@happy.engineering>
(cherry picked from commit 09c1656df9)

Co-authored-by: kaovilai <11228024+kaovilai@users.noreply.github.com>
Signed-off-by: Tiger Kaovilai <tkaovila@redhat.com>

changelogs/unreleased/9795-kaovilai

@@ -0,0 +1 @@
+Skip DeleteSnapshot when ProviderSnapshotID is empty

pkg/controller/backup_deletion_controller.go

@@ -321,6 +321,10 @@ func (r *backupDeletionReconciler) Reconcile(ctx context.Context, req ctrl.Reque
 					volumeSnapshotters[snapshot.Spec.Location] = volumeSnapshotter
 				}
 
+				if snapshot.Status.ProviderSnapshotID == "" {
+					log.WithField("volumeSnapshot", snapshot.Spec.PersistentVolumeName).Warn("Skipping snapshot deletion: empty ProviderSnapshotID")
+					continue
+				}
 				if err := volumeSnapshotter.DeleteSnapshot(snapshot.Status.ProviderSnapshotID); err != nil {
 					errs = append(errs, errors.Wrapf(err, "error deleting snapshot %s", snapshot.Status.ProviderSnapshotID).Error())
 				}

pkg/controller/backup_deletion_controller_test.go

@@ -397,6 +397,74 @@ func TestBackupDeletionControllerReconcile(t *testing.T) {
 		// Make sure snapshot was deleted
 		assert.Equal(t, 0, td.volumeSnapshotter.SnapshotsTaken.Len())
 	})
+	t.Run("empty ProviderSnapshotID skips DeleteSnapshot call", func(t *testing.T) {
+		input := defaultTestDbr()
+
+		backup := builder.ForBackup(velerov1api.DefaultNamespace, input.Spec.BackupName).Result()
+		backup.UID = "uid"
+		backup.Spec.StorageLocation = "primary"
+
+		restore1 := builder.ForRestore(backup.Namespace, "restore-1").
+			Phase(velerov1api.RestorePhaseCompleted).
+			Backup(backup.Name).
+			Result()
+
+		location := &velerov1api.BackupStorageLocation{
+			ObjectMeta: metav1.ObjectMeta{
+				Namespace: backup.Namespace,
+				Name:      "primary",
+			},
+			Spec: velerov1api.BackupStorageLocationSpec{
+				Provider: "objStoreProvider",
+				StorageType: velerov1api.StorageType{
+					ObjectStorage: &velerov1api.ObjectStorageLocation{
+						Bucket: "bucket",
+					},
+				},
+			},
+			Status: velerov1api.BackupStorageLocationStatus{
+				Phase: velerov1api.BackupStorageLocationPhaseAvailable,
+			},
+		}
+
+		snapshotLocation := &velerov1api.VolumeSnapshotLocation{
+			ObjectMeta: metav1.ObjectMeta{
+				Namespace: backup.Namespace,
+				Name:      "vsl-1",
+			},
+			Spec: velerov1api.VolumeSnapshotLocationSpec{
+				Provider: "provider-1",
+			},
+		}
+		td := setupBackupDeletionControllerTest(t, input, backup, restore1, location, snapshotLocation)
+
+		snapshots := []*volume.Snapshot{
+			{
+				Spec: volume.SnapshotSpec{
+					Location:             "vsl-1",
+					PersistentVolumeName: "pv-1",
+				},
+				Status: volume.SnapshotStatus{
+					ProviderSnapshotID: "",
+				},
+			},
+		}
+
+		pluginManager := &pluginmocks.Manager{}
+		pluginManager.On("GetVolumeSnapshotter", "provider-1").Return(td.volumeSnapshotter, nil)
+		pluginManager.On("GetDeleteItemActions").Return(nil, nil)
+		pluginManager.On("CleanupClients")
+		td.controller.newPluginManager = func(logrus.FieldLogger) clientmgmt.Manager { return pluginManager }
+
+		td.backupStore.On("GetBackupVolumeSnapshots", input.Spec.BackupName).Return(snapshots, nil)
+		td.backupStore.On("GetBackupContents", input.Spec.BackupName).Return(io.NopCloser(bytes.NewReader([]byte("hello world"))), nil)
+		td.backupStore.On("DeleteBackup", input.Spec.BackupName).Return(nil)
+
+		_, err := td.controller.Reconcile(t.Context(), td.req)
+		require.NoError(t, err)
+
+		td.backupStore.AssertCalled(t, "DeleteBackup", input.Spec.BackupName)
+	})
 	t.Run("full delete, no errors, with backup name greater than 63 chars", func(t *testing.T) {
 		backup := defaultBackup().
 			ObjectMeta(