Improve testing and incorrect tag warning

Author: OzGav

music_assistant/helpers/tags.py

@@ -291,13 +291,8 @@ def artists(self) -> tuple[str, ...]:
         if tag := self.tags.get("artists"):
             # Runtime check: mutagen returns list[str] for Vorbis multi-field
             if isinstance(tag, list) and len(tag) > 1:  # type: ignore[unreachable]
-                # Multiple ARTISTS fields in Vorbis - non-standard tagging.
-                # Should use multiple ARTIST (singular) fields instead.
-                LOGGER.warning(  # type: ignore[unreachable]
-                    "Multiple ARTISTS fields found. Use multiple ARTIST fields instead: %s",
-                    tag,
-                )
-                artists = clean_tuple(tag)
+                # Multiple ARTIST fields from Vorbis - already separated, no splitting needed
+                artists = clean_tuple(tag)  # type: ignore[unreachable]
             else:
                 # Single field (ID3 TXXX:ARTISTS) - split on semicolons
                 artists = split_items(tag)
@@ -358,13 +353,8 @@ def album_artists(self) -> tuple[str, ...]:
         if tag := self.tags.get("albumartists"):
             # Runtime check: mutagen returns list[str] for Vorbis multi-field
             if isinstance(tag, list) and len(tag) > 1:  # type: ignore[unreachable]
-                # Multiple ALBUMARTISTS fields in Vorbis - non-standard tagging.
-                LOGGER.warning(  # type: ignore[unreachable]
-                    "Multiple ALBUMARTISTS fields found. Use multiple ALBUMARTIST fields "
-                    "instead: %s",
-                    tag,
-                )
-                artists = clean_tuple(tag)
+                # Multiple ALBUMARTIST fields from Vorbis - already separated, no splitting needed
+                artists = clean_tuple(tag)  # type: ignore[unreachable]
             else:
                 # Single field (ID3 TXXX:ALBUMARTISTS) - split on semicolons
                 artists = split_items(tag)
@@ -1012,10 +1002,23 @@ def _parse_vorbis_artist_tags(tags: VCommentDict, result: dict[str, Any]) -> Non
         else:
             result["albumartist"] = albumartist_values[0]
 
-    # Explicit ARTISTS tag takes precedence if present
+    # ARTISTS (plural) is non-standard in Vorbis - it's a MusicBrainz/Picard ID3 convention.
+    # Vorbis spec recommends multiple ARTIST (singular) fields instead.
+    # Accept it but warn. See: https://xiph.org/vorbis/doc/v-comment.html
     if artists := _vorbis_get_multi(tags, "ARTISTS"):
+        LOGGER.warning(
+            "ARTISTS tag found in Vorbis file. Use multiple ARTIST fields instead: %s",
+            artists,
+        )
         result["artists"] = artists
 
+    if albumartists := _vorbis_get_multi(tags, "ALBUMARTISTS"):
+        LOGGER.warning(
+            "ALBUMARTISTS tag found in Vorbis file. Use multiple ALBUMARTIST fields instead: %s",
+            albumartists,
+        )
+        result["albumartists"] = albumartists
+
 
 def _parse_vorbis_tags(tags: VCommentDict) -> dict[str, Any]:
     """Parse Vorbis comment tags (FLAC, OGG Vorbis, OGG Opus, etc.).

tests/core/test_tags.py

@@ -17,6 +17,7 @@
 FILE_MP3 = str(RESOURCES_DIR.joinpath("MyArtist - MyTitle.mp3"))
 FILE_M4A = str(RESOURCES_DIR.joinpath("MyArtist - MyTitle.m4a"))
 FILE_FLAC = str(RESOURCES_DIR.joinpath("MultipleArtists.flac"))
+FILE_FLAC_SEMICOLON = str(RESOURCES_DIR.joinpath("ArtistWithSemicolon.flac"))
 FILE_WV = str(RESOURCES_DIR.joinpath("MyArtist - MyTitle.wv"))
 
 
@@ -488,6 +489,34 @@ def test_vorbis_multiple_artist_fields_semicolon_in_name() -> None:
     assert len(audio_tags.artists) == len(audio_tags.musicbrainz_artistids)
 
 
+async def test_flac_multiple_artist_fields_semicolon_e2e() -> None:
+    """End-to-end test: FLAC with multiple ARTIST fields, one containing semicolon.
+
+    Tests real file parsing to ensure the full pipeline correctly handles
+    artist names with semicolons when using multiple ARTIST fields per Vorbis spec.
+
+    See: https://xiph.org/vorbis/doc/v-comment.html
+    See: https://musicbrainz.org/artist/2ade7b3c-a6f1-4d00-b7f7-fc60abf25dba
+    """
+    audio_tags = await tags.async_parse_tags(FILE_FLAC_SEMICOLON)
+
+    # Verify the artists are correctly parsed without splitting on semicolons
+    assert audio_tags.artists == ("ave;new", "佐倉紗織")
+    assert "ave" not in audio_tags.artists
+    assert "new" not in audio_tags.artists
+
+    # Verify MB Artist IDs match
+    assert audio_tags.musicbrainz_artistids == (
+        "2ade7b3c-a6f1-4d00-b7f7-fc60abf25dba",
+        "822c07bd-1f8a-4fef-acdb-8acfe82fbef5",
+    )
+    assert len(audio_tags.artists) == len(audio_tags.musicbrainz_artistids)
+
+    # Verify other tags
+    assert audio_tags.title == "Call My Dears"
+    assert audio_tags.album == "Lovable"
+
+
 def test_id3_artist_tag_semicolon_single_mbid() -> None:
     """Test that single ARTIST tag with semicolon is not split when 1 MB ID exists.