fix: error handling when delete non-existent target (#627)

resolves #626
Signed-off-by: Xiaoxuan Wang <wangxiaoxuan119@gmail.com>

content/oci/storage.go

@@ -20,6 +20,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"sync"
@@ -113,7 +114,14 @@ func (s *Storage) Delete(ctx context.Context, target ocispec.Descriptor) error {
 		return fmt.Errorf("%s: %s: %w", target.Digest, target.MediaType, errdef.ErrInvalidDigest)
 	}
 	targetPath := filepath.Join(s.root, path)
-	return os.Remove(targetPath)
+	err = os.Remove(targetPath)
+	if err != nil {
+		if errors.Is(err, fs.ErrNotExist) {
+			return fmt.Errorf("%s: %s: %w", target.Digest, target.MediaType, errdef.ErrNotFound)
+		}
+		return err
+	}
+	return nil
 }
 
 // ingest write the content into a temporary ingest file.

content/oci/storage_test.go

@@ -412,4 +412,8 @@ func TestStorage_Delete(t *testing.T) {
 	if exists {
 		t.Errorf("Storage.Exists() = %v, want %v", exists, false)
 	}
+	err = s.Delete(ctx, desc)
+	if !errors.Is(err, errdef.ErrNotFound) {
+		t.Fatalf("got error = %v, want %v", err, errdef.ErrNotFound)
+	}
 }