From 9be006a79dd15ca43814924182d4c0ffdfb483e2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=A0ar=C5=ABnas=20Nejus?= <snejus@protonmail.com>
Date: Sat, 24 Jan 2026 22:36:56 +0000
Subject: [PATCH] Refactor parsing genre

---
 beetsplug/musicbrainz.py              | 34 +++++++++++++++------------
 test/plugins/factories/musicbrainz.py | 11 +++++++++
 test/plugins/test_musicbrainz.py      | 16 +++++++++----
 3 files changed, 42 insertions(+), 19 deletions(-)

diff --git a/beetsplug/musicbrainz.py b/beetsplug/musicbrainz.py
index b62537524..ba534e1a8 100644
--- a/beetsplug/musicbrainz.py
+++ b/beetsplug/musicbrainz.py
@@ -16,7 +16,7 @@
 
 from __future__ import annotations
 
-from collections import Counter
+from collections import defaultdict
 from contextlib import suppress
 from functools import cached_property
 from itertools import product
@@ -434,6 +434,23 @@ class MusicBrainzPlugin(MusicBrainzAPIMixin, MetadataSourcePlugin):
             original_day=day,
         )
 
+    def _parse_genre(self, release: Release) -> str | None:
+        if self.config["genres"]:
+            genres = [
+                *release["release_group"][self.genres_field],
+                *release.get(self.genres_field, []),
+            ]
+            count_by_genre: dict[str, int] = defaultdict(int)
+            for genre in genres:
+                count_by_genre[genre["name"]] += int(genre["count"])
+
+            return "; ".join(
+                g
+                for g, _ in sorted(count_by_genre.items(), key=lambda g: -g[1])
+            )
+
+        return None
+
     def album_info(self, release: Release) -> beets.autotag.hooks.AlbumInfo:
         """Takes a MusicBrainz release result dictionary and returns a beets
         AlbumInfo object containing the interesting data about that release.
@@ -522,6 +539,7 @@ class MusicBrainzPlugin(MusicBrainzAPIMixin, MetadataSourcePlugin):
             data_source=self.data_source,
             data_url=urljoin(BASE_URL, f"release/{release['id']}"),
             barcode=release.get("barcode"),
+            genre=genre if (genre := self._parse_genre(release)) else None,
             **self._parse_release_group(release["release_group"]),
         )
         info.va = info.artist_id == VARIOUS_ARTISTS_ID
@@ -569,20 +587,6 @@ class MusicBrainzPlugin(MusicBrainzAPIMixin, MetadataSourcePlugin):
             else:
                 info.media = "Media"
 
-        if self.config["genres"]:
-            sources = [
-                release["release_group"][self.genres_field],
-                release.get(self.genres_field, []),
-            ]
-            genres: Counter[str] = Counter()
-            for source in sources:
-                for genreitem in source:
-                    genres[genreitem["name"]] += int(genreitem["count"])
-            info.genre = "; ".join(
-                genre
-                for genre, _count in sorted(genres.items(), key=lambda g: -g[1])
-            )
-
         # We might find links to external sources (Discogs, Bandcamp, ...)
         external_ids = self.config["external_ids"].get()
         wanted_sources: set[UrlSource] = {
diff --git a/test/plugins/factories/musicbrainz.py b/test/plugins/factories/musicbrainz.py
index 36549d953..1a7cfa72b 100644
--- a/test/plugins/factories/musicbrainz.py
+++ b/test/plugins/factories/musicbrainz.py
@@ -115,3 +115,14 @@ class ReleaseGroupFactory(_IdFactory):
     secondary_types = factory.List([])
     tags = factory.List([])
     title = "Release Group"
+
+
+class GenreFactory(factory.DictFactory):
+    id = factory.Faker("uuid4")
+    count = 1
+    disambiguation = ""
+    name = "Genre"
+
+
+class TagFactory(GenreFactory):
+    name = "Tag"
diff --git a/test/plugins/test_musicbrainz.py b/test/plugins/test_musicbrainz.py
index 529f2d4b3..dd1594756 100644
--- a/test/plugins/test_musicbrainz.py
+++ b/test/plugins/test_musicbrainz.py
@@ -60,6 +60,14 @@ def release_group_factory(**kwargs) -> mb.ReleaseGroup:
     return factories.ReleaseGroupFactory.build(**kwargs)
 
 
+def genre_factory(**kwargs) -> mb.Genre:
+    return factories.GenreFactory.build(**kwargs)
+
+
+def tag_factory(**kwargs) -> mb.Tag:
+    return factories.TagFactory.build(**kwargs)
+
+
 class MusicBrainzTestCase(BeetsTestCase):
     def setUp(self):
         super().setUp()
@@ -85,8 +93,8 @@ class MusicBrainzTestCase(BeetsTestCase):
             "artist_credit": [artist_credit_factory(artist__id_base=10)],
             "date": "3001",
             "media": [],
-            "genres": [{"count": 1, "name": "GENRE"}],
-            "tags": [{"count": 1, "name": "TAG"}],
+            "genres": [genre_factory()],
+            "tags": [tag_factory()],
             "label_info": [
                 {
                     "catalog_number": "CATALOG NUMBER",
@@ -520,14 +528,14 @@ class MBAlbumInfoTest(MusicBrainzTestCase):
         config["musicbrainz"]["genres_tag"] = "genre"
         release = self._make_release()
         d = self.mb.album_info(release)
-        assert d.genre == "GENRE"
+        assert d.genre == "Genre"
 
     def test_tags(self):
         config["musicbrainz"]["genres"] = True
         config["musicbrainz"]["genres_tag"] = "tag"
         release = self._make_release()
         d = self.mb.album_info(release)
-        assert d.genre == "TAG"
+        assert d.genre == "Tag"
 
     def test_no_genres(self):
         config["musicbrainz"]["genres"] = False