From a2f0d6960ff0e1f02d15f201cb37133b7aadc83a Mon Sep 17 00:00:00 2001
From: Jens Luetjen <dublok@users.noreply.github.com>
Date: Wed, 17 Feb 2016 22:54:22 +0100
Subject: [PATCH] Avoid endless loop if all tracks are unplayable.

Limit the number of tries for changing to the nest track.
The limit is 2 * tracklist length get all tracks in a shuffled playlist.
---
 mopidy/core/playback.py | 36 ++++++++++++++++++++++++------------
 1 file changed, 24 insertions(+), 12 deletions(-)

diff --git a/mopidy/core/playback.py b/mopidy/core/playback.py
index d6c470f2..0d945b1c 100644
--- a/mopidy/core/playback.py
+++ b/mopidy/core/playback.py
@@ -252,22 +252,27 @@ class PlaybackController(object):
             return
 
         pending = self.core.tracklist.eot_track(self._current_tl_track)
-        while pending:
-            # TODO: Avoid infinite loops if all tracks are unplayable.
-            backend = self._get_backend(pending)
-            if not backend:
-                continue
+        # avoid endless loop if 'repeat' is 'true' and no track is playable
+        # * 2 -> second run to get all playable track in a shuffled playlist
+        count = self.core.tracklist.get_length() * 2
 
-            try:
-                if backend.playback.change_track(pending.track).get():
-                    self._pending_tl_track = pending
-                    break
-            except Exception:
-                logger.exception('%s backend caused an exception.',
-                                 backend.actor_ref.actor_class.__name__)
+        while pending:
+            backend = self._get_backend(pending)
+            if backend:
+                try:
+                    if backend.playback.change_track(pending.track).get():
+                        self._pending_tl_track = pending
+                        break
+                except Exception:
+                    logger.exception('%s backend caused an exception.',
+                                     backend.actor_ref.actor_class.__name__)
 
             self.core.tracklist._mark_unplayable(pending)
             pending = self.core.tracklist.eot_track(pending)
+            count -= 1
+            if not count:
+                logger.info('No playable track in the list.')
+                break
 
     def _on_tracklist_change(self):
         """
@@ -352,6 +357,9 @@ class PlaybackController(object):
 
         current = self._pending_tl_track or self._current_tl_track
         pending = tl_track or current or self.core.tracklist.next_track(None)
+        # avoid endless loop if 'repeat' is 'true' and no track is playable
+        # * 2 -> second run to get all playable track in a shuffled playlist
+        count = self.core.tracklist.get_length() * 2
 
         while pending:
             if self._change(pending, PlaybackState.PLAYING):
@@ -360,6 +368,10 @@ class PlaybackController(object):
                 self.core.tracklist._mark_unplayable(pending)
             current = pending
             pending = self.core.tracklist.next_track(current)
+            count -= 1
+            if not count:
+                logger.info('No playable track in the list.')
+                break
 
         # TODO return result?