mopidy not playing nicely with upmpdcli revisited (`addtagid` not implemented)

[wu-lee]

Describe the bug

I'm seeing something very like the bug mopidy/mopidy#1286 now, using recent releases of Mopidy, Upmpdcli and Jellyfin (details below). Tracks which play initially won't play later.

How to reproduce

Initially, things work: playing a track on Jellyfin when casting to upmpdcli, which is managing Mopidy, results in music playing.

However, something happens over time, typically when I go away and come back again to play music again. Then, nothing happens when a track is played.

Upmpd emits the following in its log whenever an attempt is made [edit: whether successful or not]:

upmpdcli_1               | 2021-03-17T11:28:32.831477362Z :3:src/upmpd.cxx:275::checkContentFormat: format check disabled
upmpdcli_1               | 2021-03-17T11:28:32.899081567Z :2:src/mpdcli.cxx:680::MPDCli::send_tag: mpd_response_finish failed for tag 0 data [Godspeed You! Black Emperor]
upmpdcli_1               | 2021-03-17T11:28:32.899203260Z :2:src/mpdcli.cxx:140::MPDCli::send_tag failed: Not implemented
upmpdcli_1               | 2021-03-17T11:28:32.899328188Z :2:src/mpdcli.cxx:143::MPDCli::send_tag server error: 0

Upmpdcli is not restarting after each attempt.

Enabling debug logging on Mopidy shows that indeed the command addtagid is being sent, and Mopidy is responding with {addtagid} Not implemented. Nothing is played. There are no errors shown in Jellyfin.

Mopidy log of an unsuccessful play mopidy.log

Restarting the Mopidy docker container can make this problem go away, but it returns again. Successful plays seem also to have the addtagid not implemented message, suggesting there may be something more to this.

Mopidy log of a successful play mopidy-2.log

(Note that Mopidy lists addtagid as an MPD command in the logs when a client session starts, included in second log file.)

Expected behaviour

I expect to be able to play tracks from Jellyfin onto Mopidy via upmpdcli, repeatably.

Environment
Please complete the following information:

• Docker containers using Alpine Linux 3.13 using the Edge repository to get upmpdcli, just main for the Mopidy container.
• Host OS is Ubuntu Focal Fossa.
• Mopidy 3.1.1 with Mopidy-MPD 3.1.0
• Umpdcli 1.4.14 (libupnpp 0.20.2)
• Jellyfin 10.6.4 as upnp client (although this also happens with BubbleUPNP)
• Mopidy run in terminal mode: /usr/bin/python3 /usr/bin/mopidy --config /data/.config/mopidy.conf
• Mopidy config config.txt
• Mopidy deps deps.txt
• Hardware is an Intel NUC6CAYB