Allow selecting either tags or genres in the includes, defaulting to genres

[aereaux]

Description

Genres is a filtered list based on what musicbrainz considers a genre, tags are all the user-submitted tags. [1]

1. https://musicbrainz.org/doc/MusicBrainz_API#:~:text=Since%20genres%20are,!).

To Do

• Documentation. (If you've added a new command-line flag, for example, find the appropriate page under docs/ to describe it.)
• Changelog. (Add an entry to docs/changelog.rst to the bottom of one of the lists near the top of the document.)
• Tests. (Very much encouraged but not strictly required.)

[github-actions]

Thank you for the PR! The changelog has not been updated, so here is a friendly reminder to check if you need to add an entry.

[codecov]

Codecov Report

❌ Patch coverage is 20.00000% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 63.70%. Comparing base (5beb3d1) to head (7ac6afc).

Files with missing lines	Patch %	Lines
beetsplug/musicbrainz.py	20.00%	6 Missing and 2 partials ⚠️

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[snejus]

To make this tidier, define this as a genres_field cached_property above the __init__ method

Suggested change

	genres_config = config["musicbrainz"]["genres"]
	if genres_config:
	genres_config = genres_config.get(str)
	if genres_config == "genres":
	self.genre_or_tag = "genre"
	elif genres_config == "tags":
	self.genre_or_tag = "tag"
	else:
	self.genre_or_tag = "genre"
	else:
	self.genre_or_tag = False
	def genres_field(self) -> str | None:
	return f"{config['musicbrainz']['genres_tag'].get()}-list"

• Use a separate configuration field genres_tag that can be either genre or tag
• Use f-string to concatenate it with -list to return the field name to be used later

[snejus]

Keep the same logic here

Suggested change

	if self.genre_or_tag:
	if self.config["genres"]:

[snejus]

Suggested change

	release["release-group"].get(self.genre_or_tag + "-list", []),
	release.get(self.genre_or_tag + "-list", []),
	release["release-group"].get(self.genres_field, []),
	release.get(self.genres_field, []),

[snejus]

Keep the genre configuration unchanged to make sure that this change is backwards-compatible.

Instead, add a new configuration genres_tag which can take either genre or tag as a value, defaulting to genre. Make it clear that this configuration is only used when genres configuration is enabled.

You will need to specify the default in the self.config.add call under the __init__ method:

                 "searchlimit": 5,
                 "genres": False,
+                "genres_tag": "genre",
                 "external_ids": {