lastgenre: Use albumartists field to improve last.fm results

beetsplug/lastgenre/__init__.py

@@ -28,7 +28,7 @@
 import traceback
 from functools import singledispatchmethod
 from pathlib import Path
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Any, Callable
 
 import pylast
 import yaml
@@ -259,9 +259,11 @@ def _resolve_genres(self, tags: list[str]) -> list[str]:
         valid_tags = [t for t in tags if self._is_valid(t)]
         return valid_tags[:count]
 
-    def fetch_genre(self, lastfm_obj):
-        """Return the genre for a pylast entity or None if no suitable genre
-        can be found. Ex. 'Electronic, House, Dance'
+    def fetch_genre(
+        self, lastfm_obj: pylast.Album | pylast.Artist | pylast.Track
+    ) -> list[str]:
+        """Return genres for a pylast entity. Returns an empty list if
+        no suitable genres are found.
         """
         min_weight = self.config["min_weight"].get(int)
         return self._tags_for(lastfm_obj, min_weight)
@@ -278,8 +280,10 @@ def _is_valid(self, genre: str) -> bool:
 
     # Cached last.fm entity lookups.
 
-    def _last_lookup(self, entity, method, *args):
-        """Get a genre based on the named entity using the callable `method`
+    def _last_lookup(
+        self, entity: str, method: Callable[..., Any], *args: str
+    ) -> list[str]:
+        """Get genres based on the named entity using the callable `method`
         whose arguments are given in the sequence `args`. The genre lookup
         is cached based on the entity name and the arguments.
 
@@ -293,31 +297,27 @@ def _last_lookup(self, entity, method, *args):
 
         key = f"{entity}.{'-'.join(str(a) for a in args)}"
         if key not in self._genre_cache:
-            args = [a.replace("\u2010", "-") for a in args]
-            self._genre_cache[key] = self.fetch_genre(method(*args))
+            args_replaced = [a.replace("\u2010", "-") for a in args]
+            self._genre_cache[key] = self.fetch_genre(method(*args_replaced))
 
         genre = self._genre_cache[key]
         self._tunelog("last.fm (unfiltered) {} tags: {}", entity, genre)
         return genre
 
-    def fetch_album_genre(self, obj):
-        """Return raw album genres from Last.fm for this Item or Album."""
+    def fetch_album_genre(self, albumartist: str, albumtitle: str) -> list[str]:
+        """Return genres from Last.fm for the album by albumartist."""
         return self._last_lookup(
-            "album", LASTFM.get_album, obj.albumartist, obj.album
+            "album", LASTFM.get_album, albumartist, albumtitle
         )
 
-    def fetch_album_artist_genre(self, obj):
-        """Return raw album artist genres from Last.fm for this Item or Album."""
-        return self._last_lookup("artist", LASTFM.get_artist, obj.albumartist)
+    def fetch_artist_genre(self, artist: str) -> list[str]:
+        """Return genres from Last.fm for the artist."""
+        return self._last_lookup("artist", LASTFM.get_artist, artist)
 
-    def fetch_artist_genre(self, item):
-        """Returns raw track artist genres from Last.fm for this Item."""
-        return self._last_lookup("artist", LASTFM.get_artist, item.artist)
-
-    def fetch_track_genre(self, obj):
-        """Returns raw track genres from Last.fm for this Item."""
+    def fetch_track_genre(self, trackartist: str, tracktitle: str) -> list[str]:
+        """Return genres from Last.fm for the track by artist."""
         return self._last_lookup(
-            "track", LASTFM.get_track, obj.artist, obj.title
+            "track", LASTFM.get_track, trackartist, tracktitle
         )
 
     # Main processing: _get_genre() and helpers.
@@ -405,14 +405,14 @@ def _try_resolve_stage(stage_label: str, keep_genres, new_genres):
         # Run through stages: track, album, artist,
         # album artist, or most popular track genre.
         if isinstance(obj, library.Item) and "track" in self.sources:
-            if new_genres := self.fetch_track_genre(obj):
+            if new_genres := self.fetch_track_genre(obj.artist, obj.title):
                 if result := _try_resolve_stage(
                     "track", keep_genres, new_genres
                 ):
                     return result
 
         if "album" in self.sources:
-            if new_genres := self.fetch_album_genre(obj):
+            if new_genres := self.fetch_album_genre(obj.albumartist, obj.album):
                 if result := _try_resolve_stage(
                     "album", keep_genres, new_genres
                 ):
@@ -421,20 +421,36 @@ def _try_resolve_stage(stage_label: str, keep_genres, new_genres):
         if "artist" in self.sources:
             new_genres = []
             if isinstance(obj, library.Item):
-                new_genres = self.fetch_artist_genre(obj)
+                new_genres = self.fetch_artist_genre(obj.artist)
                 stage_label = "artist"
             elif obj.albumartist != config["va_name"].as_str():
-                new_genres = self.fetch_album_artist_genre(obj)
+                new_genres = self.fetch_artist_genre(obj.albumartist)
                 stage_label = "album artist"
+                if not new_genres:
+                    self._tunelog(
+                        'No album artist genre found for "{}", '
+                        "trying multi-valued field...",
+                        obj.albumartist,
+                    )
+                    for albumartist in obj.albumartists:
+                        self._tunelog(
+                            'Fetching artist genre for "{}"', albumartist
+                        )
+                        new_genres += self.fetch_artist_genre(albumartist)
+                    if new_genres:
+                        stage_label = "multi-valued album artist"
             else:
                 # For "Various Artists", pick the most popular track genre.
                 item_genres = []
+                assert isinstance(obj, Album)  # Type narrowing for mypy
                 for item in obj.items():
                     item_genre = None
                     if "track" in self.sources:
-                        item_genre = self.fetch_track_genre(item)
+                        item_genre = self.fetch_track_genre(
+                            item.artist, item.title
+                        )
                     if not item_genre:
-                        item_genre = self.fetch_artist_genre(item)
+                        item_genre = self.fetch_artist_genre(item.artist)
                     if item_genre:
                         item_genres += item_genre
                 if item_genres:

docs/changelog.rst

@@ -73,6 +73,11 @@ Bug fixes:
   cancelling an edit session during import. :bug:`6104`
 - :ref:`update-cmd` :doc:`plugins/edit` fix display formatting of field changes
   to clearly show added and removed flexible fields.
+- :doc:`plugins/lastgenre`: Fix the issue where last.fm doesn't return any
+  result in the artist genre stage because "concatenation" words in the artist
+  name (like "feat.", "+", or "&") prevent it. Using the albumartists list field
+  and fetching a genre for each artist separately improves the chance of
+  receiving valid results in that stage.
 
 For plugin developers:
 

test/plugins/test_lastgenre.py

@@ -546,13 +546,13 @@ def test_sort_by_depth(self):
 def test_get_genre(config_values, item_genre, mock_genres, expected_result):
     """Test _get_genre with various configurations."""
 
-    def mock_fetch_track_genre(self, obj=None):
+    def mock_fetch_track_genre(self, trackartist, tracktitle):
         return mock_genres["track"]
 
-    def mock_fetch_album_genre(self, obj):
+    def mock_fetch_album_genre(self, albumartist, albumtitle):
         return mock_genres["album"]
 
-    def mock_fetch_artist_genre(self, obj):
+    def mock_fetch_artist_genre(self, artist):
         return mock_genres["artist"]
 
     # Mock the last.fm fetchers. When whitelist enabled, we can assume only