Fix playlist cannot be empty via Subsonic API

core/playlists.go

@@ -227,6 +227,12 @@ func (s *playlists) Update(ctx context.Context, playlistId string,
 		if public != nil {
 			pls.Public = *public
 		}
+		// Special case: The playlist is now empty
+		if len(idxToRemove) > 0 && len(pls.Tracks) == 0 {
+			if err = repo.Tracks(playlistId).DeleteAll(); err != nil {
+				return err
+			}
+		}
 		return repo.Put(pls)
 	})
 }

model/playlist.go

@@ -120,5 +120,6 @@ type PlaylistTrackRepository interface {
 	AddArtists(artistIds []string) (int, error)
 	AddDiscs(discs []DiscID) (int, error)
 	Delete(id ...string) error
+	DeleteAll() error
 	Reorder(pos int, newPos int) error
 }

persistence/playlist_repository.go

@@ -110,10 +110,10 @@ func (r *playlistRepository) Put(p *model.Playlist) error {
 		return nil
 	}
 	// Only update tracks if they were specified
-	if len(pls.Tracks) == 0 {
+	if len(pls.Tracks) > 0 {
-		return nil
+		return r.updateTracks(id, p.MediaFiles())
 	}
-	return r.updateTracks(id, p.MediaFiles())
+	return r.RefreshStatus(id)
 }
 
 func (r *playlistRepository) Get(id string) (*model.Playlist, error) {

persistence/playlist_track_repository.go

@@ -164,6 +164,18 @@ func (r *playlistTrackRepository) Delete(ids ...string) error {
 	return r.playlistRepo.renumber(r.playlistId)
 }
 
+func (r *playlistTrackRepository) DeleteAll() error {
+	if !r.isTracksEditable() {
+		return rest.ErrPermissionDenied
+	}
+	err := r.delete(Eq{"playlist_id": r.playlistId})
+	if err != nil {
+		return err
+	}
+
+	return r.playlistRepo.renumber(r.playlistId)
+}
+
 func (r *playlistTrackRepository) Reorder(pos int, newPos int) error {
 	if !r.isTracksEditable() {
 		return rest.ErrPermissionDenied