Unhandled exception in MpdSession: AttributeError: 'NoneType' object has no attribute 'uri'

[wernight]

While starting to play a YouTube result for search (usually it works), ncmpcpp stopped responding and the log Mopidy log end looks like:

INFO     New MPD connection from [::ffff:172.17.42.1]:42326
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/mopidy/utils/network.py", line 273, in recv_callback
    self.actor_ref.tell({'close': True})
  File "/usr/lib/python2.7/dist-packages/pykka/actor.py", line 437, in tell
    raise _ActorDeadError('%s not found' % self)
pykka.exceptions.ActorDeadError: MpdSession (urn:uuid:447ae1ed-a5bb-4dab-45dc-ceb3bef8bf72) not found
INFO     Youtube says: This video is unavailable. [Brandenburg]
INFO     New MPD connection from [::ffff:172.17.42.1]:47899
ERROR    Unhandled exception in MpdSession (urn:uuid:2b06674e-c7cf-42cc-a31c-8bbc5e8f548f):
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/pykka/actor.py", line 200, in _actor_loop
    response = self._handle_receive(message)
  File "/usr/lib/python2.7/dist-packages/pykka/actor.py", line 303, in _handle_receive
    return self.on_receive(message)
  File "/usr/lib/python2.7/dist-packages/mopidy/utils/network.py", line 367, in on_receive
    self.on_line_received(line)
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/session.py", line 33, in on_line_received
    response = self.dispatcher.handle_request(line)
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/dispatcher.py", line 46, in handle_request
    return self._call_next_filter(request, response, filter_chain)
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/dispatcher.py", line 67, in _call_next_filter
    return next_filter(request, response, filter_chain)
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/dispatcher.py", line 75, in _catch_mpd_ack_errors_filter
    return self._call_next_filter(request, response, filter_chain)
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/dispatcher.py", line 67, in _call_next_filter
    return next_filter(request, response, filter_chain)
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/dispatcher.py", line 88, in _authenticate_filter
    return self._call_next_filter(request, response, filter_chain)
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/dispatcher.py", line 67, in _call_next_filter
    return next_filter(request, response, filter_chain)
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/dispatcher.py", line 104, in _command_list_filter
    response = self._call_next_filter(request, response, filter_chain)
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/dispatcher.py", line 67, in _call_next_filter
    return next_filter(request, response, filter_chain)
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/dispatcher.py", line 133, in _idle_filter
    response = self._call_next_filter(request, response, filter_chain)
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/dispatcher.py", line 67, in _call_next_filter
    return next_filter(request, response, filter_chain)
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/dispatcher.py", line 146, in _add_ok_filter
    response = self._call_next_filter(request, response, filter_chain)
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/dispatcher.py", line 67, in _call_next_filter
    return next_filter(request, response, filter_chain)
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/dispatcher.py", line 158, in _call_handler_filter
    response = self._format_response(self._call_handler(request))
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/dispatcher.py", line 172, in _call_handler
    return protocol.commands.call(tokens, context=self.context)
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/protocol/__init__.py", line 178, in call
    return self.handlers[tokens[0]](context, *tokens[1:])
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/protocol/__init__.py", line 156, in validate
    return func(**callargs)
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/protocol/status.py", line 42, in currentsong
    tl_track, position=position, stream_title=stream_title)
  File "/usr/lib/python2.7/dist-packages/mopidy/mpd/translator.py", line 36, in track_to_mpd_format
    ('file', track.uri or ''),
AttributeError: 'NoneType' object has no attribute 'uri'

From there on, ncpmcpp cannot successfully reconnect. Or it can connect but it's like there is a lag of one minute and nothing responds, so the server is like dead.

[wernight]

YouTube music video matched was https://youtu.be/ybjJ4283OU8 searching Brandenburg Concertos.

[jodal]

@adamcik Wouldn't the response with the None-track returned by Mopidy-YouTube be rejected by Mopidy 1.1 and not affect the response from other backends? If so, I think we've done what we can with this issue in Mopidy core, and the remainder is a Mopidy-YouTube bug.

[jodal]

@dz0ny I'm assigning this to you on the assumption that a fix in Mopidy-YouTube is needed.

[adamcik]

@jodal sounds about right, should we just open a new m-y bug and close this?

[jodal]

Might as well.

[jodal]

I believe this was fixed by natumbri/mopidy-youtube#35.