Support searching non-album tracks

[mgoltzsche]

Currently, when I search for a singleton track (not part of an album) within my beets library via mopidy-beets, I don't get any result.

Problem

When I enter "Bertrand" into the mopidy search (knowing that I have a matching singleton track within the library), mopidy-beets logs:

ERROR    2023-12-05 23:18:36,143 [1:BeetsBackend-3 (_actor_loop)] mopidy_beets.client
  Beets - Request http://127.0.0.1:8337/album/None, failed with status code 404
WARNING  2023-12-05 23:18:36,143 [1:Core-12 (_actor_loop)] mopidy.core.library
  BeetsBackend does not implement library.search() with "exact" support. Please upgrade it.
ERROR    2023-12-05 23:18:36,155 [1:BeetsBackend-3 (_actor_loop)] mopidy_beets.client
  Beets - Request http://127.0.0.1:8337/album/None, failed with status code 404
WARNING  2023-12-05 23:18:36,155 [1:Core-12 (_actor_loop)] mopidy.core.library
  BeetsBackend does not implement library.search() with "exact" support. Please upgrade it.

Correspondingly, beets logs:

127.0.0.1 - - [05/Dec/2023 23:18:36] "GET /item/query/artist:Bertrand HTTP/1.1" 200 -
127.0.0.1 - - [05/Dec/2023 23:18:36] "GET /album/None HTTP/1.1" 404 -
127.0.0.1 - - [05/Dec/2023 23:18:36] "GET /item/query/Bertrand HTTP/1.1" 200 -
127.0.0.1 - - [05/Dec/2023 23:18:36] "GET /album/None HTTP/1.1" 404 -

Looking into the beets query result JSON shows that the album_id is null, indeed:

$ curl -s http://localhost:8337/item/query/Bertrand
{"results":[{"id": 1, "album_id": null, "title": "\u00c7a plane pour moi", ...

Apparently, mopidy-beets submits the search query to beets correctly, reads the result containing the matching track but then tries to query the containing album although the track is not associated with an album.

Proposed solution

Let mopidy-beets also add singleton tracks (that are not associated with an album) to the search result, not trying to resolve None albums.

Environment

I am using

• beets 1.6.0
• mopidy 3.4.2
• mopidy-beets 4.0.1