Files
Deluan Quintão bd9fa1c602 feat(listenbrainz): match collaboration top-songs via all credited artist MBIDs (#5670)
* refactor(agents): drop single Artist fields from Song, keep only Artists

Song now represents credited artists solely via the Artists slice; the
single Artist/ArtistMBID fields and the ArtistList passthrough are removed.
Equals continues to hash the whole value.

* refactor(lastfm,listenbrainz): build Song.Artists in built-in agents

Last.fm and ListenBrainz now populate the Artists slice directly. For
ListenBrainz top songs, all credited artist MBIDs are mapped (the combined
display name on the first credit plus MBID-only collaborators) instead of
keeping only the first MBID, feeding the matcher's per-MBID specificity.

* refactor(external): set Song.Artists in top-songs enrichment

getMatchingTopSongs now seeds an Artists entry from the known artist when a
song carries none, replacing the single Artist/ArtistMBID writes.

* refactor(plugins): fold single-artist SongRef into Song.Artists

SongRef keeps its single Artist/ArtistMBID fields as part of the plugin wire
contract; songRefToAgentSong now folds them into a one-element Artists list
when a plugin sends no artists array.

* refactor(matcher): read Song.Artists directly

groupQueries consumes s.Artists now that ArtistList is gone; test inputs
build the Artists slice.

* fix(matcher): keep MBID-only artists as identity signals

Review follow-up: an artist credited only by MBID (empty ID and name) was
dropped before resolution in four places, defeating the multi-MBID matching
path this PR adds.

- matcher.groupQueries: treat a non-empty MBID as a usable artist signal
- external.getMatchingTopSongs: backfill the primary credit's name/MBID when
  the agent left them empty
- plugins.songRefToAgentSong: fold a single-artist SongRef when only ArtistMBID
  is set (not just when Artist name is set)
- listenbrainz.topSongArtists: return nil instead of an empty-name placeholder
  when neither name nor MBIDs are present

* fix(external): only backfill top-song artist onto an unnamed credit

Review follow-up (codex P2): the previous backfill stamped the queried
artist's MBID onto Artists[0] whenever it was empty, even when that credit
already named a different (e.g. featured) artist — producing a mismatched
name+MBID pair that could mis-rank matches. Now only an unnamed first credit
is filled (it is, by construction, the queried artist); an already-named
credit is left untouched.

Signed-off-by: Deluan <deluan@navidrome.org>

---------

Signed-off-by: Deluan <deluan@navidrome.org>
2026-06-26 17:06:14 -04:00
..
2022-07-26 16:53:17 -04:00

This folder abstracts metadata lookup into "agents". Each agent can be implemented to get as much info as the external source provides, by using a granular set of interfaces (see interfaces).

A new agent must comply with these simple implementation rules:

  1. Implement the AgentName() method. It just returns the name of the agent for logging purposes.
  2. Implement one or more of the *Retriever() interfaces. That's where the agent's logic resides.
  3. Register itself (in its init() function).

For an agent to be used it needs to be listed in the Agents config option (default is "deezer,lastfm"). The order dictates the priority of the agents

For a simple Agent example, look at the local_agent agent source code.