Funkwhale cannot handle multiple artists for a single track/album
Some files get the following error:
$file.flac: IntegrityError duplicate key value violates unique constraint "music_artist_mbid_0b814e0b_uniq"
DETAIL: Key (mbid)=(b3d3a008-aa3e-4ddc-b1ec-bef10bc1a22e) already exists.
Here I'm guessing that funkwhale isn't processing multiple MusicBrainz Artist Ids on one track correctly. As an example I have "Everyone's Throne (Bard Song)" by "Daniel Ran & Joao Guerra". The AcoustId is "f294429a-f548-42dd-8301-40d2502a3464". Here the "MusicBrainz Artist Id" is an array with the two artists Ids ("b3d3a008-aa3e-4ddc-b1ec-bef10bc1a22e" and "0a17a439-40a7-4914-aa72-b5acf645a0dc"). I'm guessing funkwhale is trying to add the Artist "Daniel Ran & Joao Guerra" with the Id "b3d3a008-aa3e-4ddc-b1ec-bef10bc1a22e" and is failing, because this artist-id is already taken.
In addition I also noticed the error appearing with some album-ids. This affects at least flac and ogg, probably mp3 is also affected.