Fix crash for Spotify users with playlist folders

docs/changes.rst

@@ -21,6 +21,10 @@ No description yet.
   - Support high bitrate (320k) audio. See
     :attr:`mopidy.settings.SPOTIFY_HIGH_BITRATE` for details.
 
+  - Catch and log error caused by playlist folder boundaries being threated as
+    normal playlists. More permanent fix requires support for checking playlist
+    types in pyspotify.
+
 - Last.fm frontend:
 
   - If you use the Last.fm frontend, you need to upgrade to pylast 0.5.

mopidy/backends/libspotify/session_manager.py

@@ -54,6 +54,7 @@ class LibspotifySessionManager(SpotifySessionManager, BaseThread):
         for spotify_playlist in session.playlist_container():
             playlists.append(
                 LibspotifyTranslator.to_mopidy_playlist(spotify_playlist))
+        playlists = filter(None, playlists)
         self.core_queue.put({
             'command': 'set_stored_playlists',
             'playlists': playlists,

mopidy/backends/libspotify/translator.py

@@ -1,11 +1,14 @@
 import datetime as dt
+import logging
 
-from spotify import Link
+from spotify import Link, SpotifyError
 
 from mopidy import settings
 from mopidy.backends.libspotify import ENCODING
 from mopidy.models import Artist, Album, Track, Playlist
 
+logger = logging.getLogger('mopidy.backends.libspotify.translator')
+
 class LibspotifyTranslator(object):
     @classmethod
     def to_mopidy_artist(cls, spotify_artist):
@@ -47,8 +50,15 @@ class LibspotifyTranslator(object):
     def to_mopidy_playlist(cls, spotify_playlist):
         if not spotify_playlist.is_loaded():
             return Playlist(name=u'[loading...]')
-        return Playlist(
-            uri=str(Link.from_playlist(spotify_playlist)),
-            name=spotify_playlist.name().decode(ENCODING),
-            tracks=[cls.to_mopidy_track(t) for t in spotify_playlist],
-        )
+        # FIXME Replace this try-except with a check on the playlist type,
+        # which is currently not supported by pyspotify, to avoid handling
+        # playlist folder boundaries like normal playlists.
+        try:
+            return Playlist(
+                uri=str(Link.from_playlist(spotify_playlist)),
+                name=spotify_playlist.name().decode(ENCODING),
+                tracks=[cls.to_mopidy_track(t) for t in spotify_playlist],
+            )
+        except SpotifyError, e:
+            logger.warning(u'Failed translating Spotify playlist '
+                '(probably a playlist folder boundary): %s', e)