Migrate arranger -> arrangers

Author: snejus

beets/autotag/hooks.py

@@ -136,17 +136,18 @@ class Info(AttrDict[Any]):
 
     IGNORED_FIELDS: ClassVar[set[str]] = {"data_url"}
     MEDIA_FIELD_MAP: ClassVar[dict[str, str]] = {}
+    LEGACY_TO_LIST_FIELD: ClassVar[dict[str, str]] = {"genre": "genres"}
 
     @cached_classproperty
     def nullable_fields(cls) -> set[str]:
         """Return fields that may be cleared when new metadata is applied."""
         return set(config["overwrite_null"][cls.type.lower()].as_str_seq())
 
     def __setitem__(self, key: str, value: Any) -> None:
-        # handle info.genre = "abc" and info["genre"] = "abc"
-        if key == "genre":
-            self["genres"] = self._get_list_from_string_value(
-                "genre", "genres", value, self["genres"]
+        # handle legacy info.str_field = "abc" and info["str_field"] = "abc"
+        if list_field := self.LEGACY_TO_LIST_FIELD.get(key):
+            self[list_field] = self._get_list_from_string_value(
+                key, list_field, value, self[list_field]
             )
         else:
             super().__setitem__(key, value)
@@ -387,23 +388,13 @@ class TrackInfo(Info):
         "track_id": "mb_trackid",
         "medium_index": "track",
     }
-
-    def __setitem__(self, key: str, value: Any) -> None:
-        # handle info.remixer = "abc" and info["remixer"] = "abc"
-        if key == "remixer":
-            self["remixers"] = self._get_list_from_string_value(
-                "remixer", "remixers", value, self["remixers"]
-            )
-        elif key == "lyricist":
-            self["lyricists"] = self._get_list_from_string_value(
-                "lyricist", "lyricists", value, self["lyricists"]
-            )
-        elif key == "composer":
-            self["composers"] = self._get_list_from_string_value(
-                "composer", "composers", value, self["composers"]
-            )
-        else:
-            super().__setitem__(key, value)
+    LEGACY_TO_LIST_FIELD: ClassVar[dict[str, str]] = {
+        **Info.LEGACY_TO_LIST_FIELD,
+        "remixer": "remixers",
+        "lyricist": "lyricists",
+        "composer": "composers",
+        "arranger": "arrangers",
+    }
 
     @property
     def id(self) -> str | None:
@@ -438,7 +429,7 @@ def raw_data(self) -> JSONDict:
     def __init__(
         self,
         *,
-        arranger: str | None = None,
+        arrangers: list[str] | None = None,
         bpm: str | None = None,
         composers: list[str] | None = None,
         composer_sort: str | None = None,
@@ -460,7 +451,7 @@ def __init__(
         work_disambig: str | None = None,
         **kwargs,
     ) -> None:
-        self.arranger = arranger
+        self.arrangers = arrangers
         self.bpm = bpm
         self.composers = composers
         self.composer_sort = composer_sort

beets/library/library.py

@@ -26,6 +26,7 @@ class Library(dbcore.Database):
         (migrations.MultiRemixerFieldMigration, (Item,)),
         (migrations.MultiLyricistFieldMigration, (Item,)),
         (migrations.MultiComposerFieldMigration, (Item,)),
+        (migrations.MultiArrangerFieldMigration, (Item,)),
     )
 
     def __init__(

beets/library/migrations.py

@@ -131,6 +131,13 @@ class MultiComposerFieldMigration(MultiValueFieldMigration):
     list_field = "composers"
 
 
+class MultiArrangerFieldMigration(MultiValueFieldMigration):
+    """Backfill multi-value arrangers from legacy single-string arranger data."""
+
+    str_field = "arranger"
+    list_field = "arrangers"
+
+
 class LyricsRow(NamedTuple):
     id: int
     lyrics: str

beets/library/models.py

@@ -662,7 +662,7 @@ class Item(LibModel):
         "work": types.STRING,
         "mb_workid": types.STRING,
         "work_disambig": types.STRING,
-        "arranger": types.STRING,
+        "arrangers": types.MULTI_VALUE_DSV,
         "grouping": types.STRING,
         "year": types.PaddedInt(4),
         "month": types.PaddedInt(2),

beets/test/_common.py

@@ -78,7 +78,7 @@ def item(lib=None, **kwargs):
         genres=["the genre"],
         lyricists=["the lyricist"],
         composers=["the composer"],
-        arranger="the arranger",
+        arrangers=["the arranger"],
         grouping="the grouping",
         work="the work title",
         mb_workid="the work musicbrainz id",

beetsplug/musicbrainz.py

@@ -399,14 +399,14 @@ def track_info(
             info.composers = composer
             info.composer_sort = ", ".join(composer_sort)
 
-        arranger = []
+        arrangers = []
         for artist_relation in recording.get("artist-relations", ()):
             if "type" in artist_relation:
                 type = artist_relation["type"]
                 if type == "arranger":
-                    arranger.append(artist_relation["artist"]["name"])
-        if arranger:
-            info.arranger = ", ".join(arranger)
+                    arrangers.append(artist_relation["artist"]["name"])
+        if arrangers:
+            info.arrangers = arrangers
 
         # Supplementary fields provided by plugins
         extra_trackdatas = plugins.send("mb_track_extract", data=recording)

docs/changelog.rst

@@ -22,12 +22,12 @@ New features
   deprecate ``overwrite``.
 - :doc:`plugins/autobpm`: The "BPM already exists for item" log message can now
   be hidden with the ``--quiet`` flag.
-- Store track remixers, lyricists, and composers in the multi-value
-  ``remixers``, ``lyricists``, and ``composers`` fields instead of the legacy
-  single-value ``remixer``, ``lyricist``, and ``composer`` fields. Existing
-  libraries are migrated automatically, and :doc:`plugins/musicbrainz` now
-  preserves each MusicBrainz ``remixer``, ``lyricist``, and ``composer``
-  relation as a separate value.
+- Store track remixers, lyricists, composers, and arrangers in the multi-value
+  ``remixers``, ``lyricists``, ``composers``, and ``arrangers`` fields instead
+  of the legacy single-value ``remixer``, ``lyricist``, ``composer``, and
+  ``arranger`` fields. Existing libraries are migrated automatically, and
+  :doc:`plugins/musicbrainz` now preserves each MusicBrainz ``remixer``,
+  ``lyricist``, ``composer``, and ``arranger`` relation as a separate value.
 
 Bug fixes
 ~~~~~~~~~
@@ -43,9 +43,13 @@ Bug fixes
   prepending the full combined artist credit as the first element for
   multi-artist releases. :bug:`6470`
 
-..
-    For plugin developers
-    ~~~~~~~~~~~~~~~~~~~~~
+For plugin developers
+~~~~~~~~~~~~~~~~~~~~~
+
+- If you maintain a metadata source plugin that populates any of ``arranger``,
+  ``composer``, ``lyricist``, ``remixer`` fields, update it to populate the
+  respective multi-value fields instead (``arrangers``, ``composers``,
+  ``lyricists``, ``remixers``).
 
 ..
     Other changes

docs/reference/cli.rst

@@ -268,8 +268,8 @@ artist sort name into the artist field for all your tracks, and ``beet modify
 title='$track $title'`` will add track numbers to their title metadata.
 
 To adjust a multi-valued field, such as ``genres``, ``remixers``, ``lyricists``,
-or ``composers``, separate the values with |semicolon_space|. For example,
-``beet modify genres="rock; pop"``.
+``composers``, or ``arrangers``, separate the values with |semicolon_space|. For
+example, ``beet modify genres="rock; pop"``.
 
 The ``-a`` option changes to querying album fields instead of track fields and
 also enables to operate on albums in addition to the individual tracks. Without

docs/reference/pathformat.rst

@@ -80,8 +80,8 @@ These functions are built in to beets:
   then returns the next ``count`` items joined by ``join``.
 
   This is especially useful for multi-valued fields like ``artists``,
-  ``genres``, ``remixers``, ``lyricists``, or ``composers`` where you may only
-  want the first value or a limited number of values in a path.
+  ``genres``, ``remixers``, ``lyricists``, ``composers``, or ``arrangers`` where
+  you may only want the first value or a limited number of values in a path.
 
   Defaults:
 
@@ -236,6 +236,7 @@ Ordinary metadata:
 - albumartist_credit
 - genre
 - genres: The track genres as a multi-valued field.
+- arrangers: The track arrangers as a multi-valued field.
 - composers: The track composers as a multi-valued field.
 - lyricists: The track lyricists as a multi-valued field.
 - remixers: The track remixers as a multi-valued field.

docs/reference/query.rst

@@ -96,8 +96,8 @@ Recall that ``-a`` makes the ``list`` command show albums instead of individual
 tracks, so this command shows me all the releases I have from this year.
 
 For multi-valued tags (such as ``artists``, ``albumartists``, ``remixers``,
-``lyricists``, or ``composers``), a regular expression search must be used to
-search for a single value within the multi-valued tag.
+``lyricists``, ``composers``, or ``arrangers``), a regular expression search
+must be used to search for a single value within the multi-valued tag.
 
 Note that you can filter albums by querying tracks fields and vice versa: