Fix crash in 'playlistinfo' when called with a songpos not matching an CPID (fixes #162)

docs/changes.rst

@@ -14,6 +14,10 @@ v0.8 (in development)
   and various client support. Requires gevent, which currently is not a
   dependency of Mopidy.
 
+- Fixed bug when the MPD command `playlistinfo` is used with a track position.
+  Track position and CPID was intermixed, so it would cause a crash if a CPID
+  matching the track position didn't exist. (Fixes: :issue:`162`)
+
 
 v0.7.3 (2012-08-11)
 ===================

mopidy/frontends/mpd/protocol/current_playlist.py

@@ -243,7 +243,7 @@ def playlistinfo(context, songpos=None,
     """
     if songpos is not None:
         songpos = int(songpos)
-        cp_track = context.backend.current_playlist.get(cpid=songpos).get()
+        cp_track = context.backend.current_playlist.cp_tracks.get()[songpos]
         return track_to_mpd_format(cp_track, position=songpos)
     else:
         if start is None:

tests/frontends/mpd/protocol/current_playlist_test.py

@@ -285,6 +285,8 @@ class CurrentPlaylistHandlerTest(protocol.BaseTestCase):
         self.assertInResponse(u'OK')
 
     def test_playlistinfo_with_songpos(self):
+        # Make the track's CPID not match the playlist position
+        self.backend.current_playlist.cp_id = 17
         self.backend.current_playlist.append([
             Track(name='a'), Track(name='b'), Track(name='c'),
             Track(name='d'), Track(name='e'), Track(name='f'),