Merge pull request #2520 from ywk253100/ignore_path_not_found_error

Ignore path not found error when look up tags

registry/storage/tagstore.go

@@ -122,17 +122,20 @@ func (ts *tagStore) Untag(ctx context.Context, tag string) error {
 		name: ts.repository.Named().Name(),
 		tag:  tag,
 	})
-
+	if err != nil {
-	switch err.(type) {
-	case storagedriver.PathNotFoundError:
-		return distribution.ErrTagUnknown{Tag: tag}
-	case nil:
-		break
-	default:
 		return err
 	}
 
-	return ts.blobStore.driver.Delete(ctx, tagPath)
+	if err := ts.blobStore.driver.Delete(ctx, tagPath); err != nil {
+		switch err.(type) {
+		case storagedriver.PathNotFoundError:
+			return nil // Untag is idempotent, we don't care if it didn't exist
+		default:
+			return err
+		}
+	}
+
+	return nil
 }
 
 // linkedBlobStore returns the linkedBlobStore for the named tag, allowing one
@@ -179,6 +182,10 @@ func (ts *tagStore) Lookup(ctx context.Context, desc distribution.Descriptor) ([
 		tagLinkPath, err := pathFor(tagLinkPathSpec)
 		tagDigest, err := ts.blobStore.readlink(ctx, tagLinkPath)
 		if err != nil {
+			switch err.(type) {
+			case storagedriver.PathNotFoundError:
+				continue
+			}
 			return nil, err
 		}
 

registry/storage/tagstore_test.go

@@ -84,8 +84,8 @@ func TestTagStoreUnTag(t *testing.T) {
 	desc := distribution.Descriptor{Digest: "sha256:bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"}
 
 	err := tags.Untag(ctx, "latest")
-	if err == nil {
+	if err != nil {
-		t.Errorf("Expected error untagging non-existant tag")
+		t.Error(err)
 	}
 
 	err = tags.Tag(ctx, "latest", desc)