mpdstats records a skip when stopping playback

[aereaux]

Problem

I am using the mpdstats plugin. Running beet mpdstats and then starting a song playing in mpd and then stopping it makes mpdstats record a skip and adjust the song rating downwards, even though that song remains at the beginning of the mpd playlist (i.e. it's not actually skipped). Interestingly pausing and then later stopping seems to not cause this problem.

Setup

• OS: Arch Linux
• Python version: 3.8.5
• beets version: b89a265
• Turning off plugins made problem go away (yes/no): Well... yes?

My configuration (output of beet config) is:

plugins: parentwork scrub info mbsync alternatives chroma mpdstats
directory: ~/music/beets/

paths:
    default: '%ifdef{parent_composer_sort,$parent_composer_sort,[unknown]}/%ifdef{parentwork_date,$parentwork_date - }%ifdef{parentwork,$parentwork,[unknown]}/%ifdef{year,$year - }$album%aunique{album year,albumartist albumtype label catalognum albumdisambig releasegroupdisambig}/$track $title'

import:
    from_scratch: yes
    move: yes
acoustid:
    apikey: REDACTED
alternatives:
    aphone:
        directory: /home/user/music/aphone/
        formats: opus
        query: ''
parentwork:
    auto: no
    force: no
chroma:
    auto: yes
mpd:
    music_directory: /home/user/music/beets
    rating: yes
    rating_mix: 0.75
    host: localhost
    port: 6600
    password: REDACTED
scrub:
    auto: yes

[aereaux]

Looking at this a bit more, it looks like this happens because handle_song_change is called before the expected end time of the song, so it sorta looks like a skip. Perhaps we could check the state of the playlist? Not sure what the best way to fix this would be.

[sampsyo]

Indeed; sounds like trouble! I'm not too familiar with the inner workings of the "state machine" that makes mpdstats tick, but maybe there's a way to tell whether handle_song_change happens when we're just paused on the current song vs. now playing a different song?

[aereaux]

It's a little more complicated than that, I think. mpd has the ability to pause or stop, and the latter is more like just pausing back to the beginning of the current track. Beets mpdstats already seems to report pauses (which work fine) and stops, but we can't just change the handling of stops wholesale because I think that it also stops at the end of the playlist/queue (although I need to do some more testing for this).

[aereaux]

OK, I looked into this more and created a PR with my best idea for how to fix this.