Swap Discogs genres and styles

[snejus]

discogs: Swap genre and style field mapping

Fixes #6390

Fixes the semantic mismatch between Discogs' taxonomy and beets' fields. In Discogs, genres are broad (e.g. "Electronic") and styles are specific (e.g. "Techno"). Previously, beets stored them the wrong way around.

What changed

In get_album_info, the source fields are swapped:

• genres (beets) now reads from Discogs styles — the specific values
• style (beets) now reads from Discogs genres — the broader values

The append_style_genre config option retains its original intent: append broader style values to genres when enabled. Only the data source for each field changed, not the logic.

[Copilot]

Pull request overview

PR swap Discogs genre/style mapping so beets fields match Discogs meaning: Discogs genres are broad, Discogs styles are specific.

Changes:

• In Discogs plugin, read beets genres from Discogs styles, and beets style from Discogs genres.
• Update Discogs plugin tests to cover the swapped mapping.
• Update Discogs plugin docs + changelog entry for new mapping.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 6 comments.

File	Description
beetsplug/discogs/__init__.py	Swap Discogs genres/styles inputs when building AlbumInfo.style and AlbumInfo.genres.
test/plugins/test_discogs.py	Adjust release fixture + assertions for swapped mapping; rename one test.
docs/plugins/discogs.rst	Update append_style_genre + separator docs to describe new semantics.
docs/changelog.rst	Add changelog entry describing the Discogs mapping change.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.01%. Comparing base (74007ec) to head (69af3cc).
⚠️ Report is 2 commits behind head on master.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #6478   +/-   ##
=======================================
  Coverage   70.01%   70.01%           
=======================================
  Files         146      146           
  Lines       18505    18505           
  Branches     3010     3010           
=======================================
  Hits        12957    12957           
  Misses       4920     4920           
  Partials      628      628           

Files with missing lines	Coverage Δ
beetsplug/discogs/__init__.py	67.28% <100.00%> (ø)

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[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

[Copilot]

grug see docstring talk about "style is empty" but test now empties release.data["genres"] (since beets style reads Discogs genres). please align names (either change wording or change which field emptied) so test not confuse.

[Copilot]

grug see separator docs still say "broader Discogs style values" but style field now built from Discogs genres (broader). please update sentence to say Discogs genre values (or just values stored in style).

Suggested change

	How to join the broader Discogs style values into the ``style`` field
	string.
	How to join the Discogs genre values stored in the ``style`` field into a
	single string.

[Copilot]

grug see genres and styles variables point at lists inside result.data. genres.extend(styles) will mutate result.data["styles"] in-place when option on. that make weird side effect and can duplicate if get_album_info called twice on same Release. safer: copy lists (ex list(...)) before extend.

Suggested change

	styles: list[str] = result.data.get("genres") or []
	genres: list[str] = result.data.get("styles") or []
	raw_styles = result.data.get("genres") or []
	raw_genres = result.data.get("styles") or []
	styles: list[str] = list(raw_styles)
	genres: list[str] = list(raw_genres)