Add custom_tags_only mode for mbpseudo plugin

beetsplug/mbpseudo.py

@@ -20,6 +20,7 @@ import traceback
 from copy import deepcopy
 from typing import TYPE_CHECKING, Any, Iterable, Sequence
 
+import mediafile
 import musicbrainzngs
 from typing_extensions import override
 
@@ -49,10 +50,49 @@ class MusicBrainzPseudoReleasePlugin(MusicBrainzPlugin):
 
         self._release_getter = musicbrainzngs.get_release_by_id
 
-        self.config.add({"scripts": []})
+        self.config.add(
+            {
+                "scripts": [],
+                "custom_tags_only": False,
+                "album_custom_tags": {
+                    "album_transl": "album",
+                    "album_artist_transl": "artist",
+                },
+                "track_custom_tags": {
+                    "title_transl": "title",
+                    "artist_transl": "artist",
+                },
+            }
+        )
+
         self._scripts = self.config["scripts"].as_str_seq()
         self._log.debug("Desired scripts: {0}", self._scripts)
 
+        album_custom_tags = self.config["album_custom_tags"].get().keys()
+        track_custom_tags = self.config["track_custom_tags"].get().keys()
+        self._log.debug(
+            "Custom tags for albums and tracks: {0} + {1}",
+            album_custom_tags,
+            track_custom_tags,
+        )
+        for custom_tag in album_custom_tags | track_custom_tags:
+            if not isinstance(custom_tag, str):
+                continue
+
+            media_field = mediafile.MediaField(
+                mediafile.MP3DescStorageStyle(custom_tag),
+                mediafile.MP4StorageStyle(
+                    f"----:com.apple.iTunes:{custom_tag}"
+                ),
+                mediafile.StorageStyle(custom_tag),
+                mediafile.ASFStorageStyle(custom_tag),
+            )
+            try:
+                self.add_media_field(custom_tag, media_field)
+            except ValueError:
+                # ignore errors due to duplicates
+                pass
+
         self.register_listener("pluginload", self._on_plugins_loaded)
         self.register_listener("album_matched", self._adjust_final_album_match)
 
@@ -107,6 +147,11 @@ class MusicBrainzPseudoReleasePlugin(MusicBrainzPlugin):
                 pseudo_release = super().album_info(
                     raw_pseudo_release["release"]
                 )
+
+                if self.config["custom_tags_only"].get(bool):
+                    self._add_custom_tags(official_release, pseudo_release)
+                    return official_release
+                else:
                     return PseudoAlbumInfo(
                         pseudo_release=_merge_pseudo_and_actual_album(
                             pseudo_release, official_release
@@ -167,6 +212,23 @@ class MusicBrainzPseudoReleasePlugin(MusicBrainzPlugin):
         else:
             return None
 
+    def _add_custom_tags(
+        self,
+        official_release: AlbumInfo,
+        pseudo_release: AlbumInfo,
+    ):
+        for tag_key, pseudo_key in (
+            self.config["album_custom_tags"].get().items()
+        ):
+            official_release[tag_key] = pseudo_release[pseudo_key]
+
+        track_custom_tags = self.config["track_custom_tags"].get().items()
+        for track, pseudo_track in zip(
+            official_release.tracks, pseudo_release.tracks
+        ):
+            for tag_key, pseudo_key in track_custom_tags:
+                track[tag_key] = pseudo_track[pseudo_key]
+
     def _adjust_final_album_match(self, match: AlbumMatch):
         album_info = match.info
         if isinstance(album_info, PseudoAlbumInfo):

docs/plugins/mbpseudo.rst

@@ -23,13 +23,18 @@ Since this plugin first searches for official releases from MusicBrainz, all
 options from the `musicbrainz` plugin's :ref:`musicbrainz-config` are supported,
 but they must be specified under `mbpseudo` in the configuration file.
 Additionally, the configuration expects an array of scripts that are desired for
-the pseudo-releases. Therefore, the minimum configuration for this plugin looks
-like this:
+the pseudo-releases. For ``artist`` in particular, keep in mind that even
+pseudo-releases might specify it with the original script, so you should also
+configure import :ref:`languages` to give artist aliases more priority.
+Therefore, the minimum configuration for this plugin looks like this:
 
 .. code-block:: yaml
 
     plugins: mbpseudo # remove musicbrainz
 
+    import:
+        languages: en
+
     mbpseudo:
         scripts:
         - Latn
@@ -37,7 +42,7 @@ like this:
 Note that the `search_limit` configuration applies to the initial search for
 official releases, and that the `data_source` in the database will be
 "MusicBrainz". Nevertheless, `data_source_mismatch_penalty` must also be
-specified under `mbpseudo` (see also
+specified under `mbpseudo` if desired (see also
 :ref:`metadata-source-plugin-configuration`). An example with multiple data
 sources may look like this:
 
@@ -45,6 +50,9 @@ sources may look like this:
 
     plugins: mbpseudo deezer
 
+    import:
+        languages: en
+
     mbpseudo:
         data_source_mismatch_penalty: 0
         scripts:
@@ -52,3 +60,44 @@ sources may look like this:
 
     deezer:
         data_source_mismatch_penalty: 0.2
+
+By default, the data from the pseudo-release will be used to create a proposal
+that is independent from the official release and sets all properties in its
+metadata. It's possible to change the configuration so that some information
+from the pseudo-release is instead added as custom tags, keeping the metadata
+from the official release:
+
+.. code-block:: yaml
+
+    mbpseudo:
+        # other config not shown
+        custom_tags_only: yes
+
+The default custom tags with this configuration are specified as mappings where
+the keys define the tag names and the values define the pseudo-release property
+that will be used to set the tag's value:
+
+.. code-block:: yaml
+
+    mbpseudo:
+        album_custom_tags:
+            album_transl: album
+            album_artist_transl: artist
+        track_custom_tags:
+            title_transl: title
+            artist_transl: artist
+
+Note that the information for each set of custom tags corresponds to different
+metadata levels (album or track level), which is why ``artist`` appears twice
+even though it effectively references album artist and track artist
+respectively.
+
+If you want to modify any mapping under ``album_custom_tags`` or
+``track_custom_tags``, you must specify *everything* for that set of tags in
+your configuration file because any customization replaces the whole dictionary
+of mappings for that level.
+
+.. note::
+
+    These custom tags are also added to the music files, not only to the
+    database.

test/plugins/test_mbpseudo.py

@@ -223,3 +223,45 @@ class TestMBPseudoPlugin(PluginMixin):
         assert match.info.data_source == "MusicBrainz"
         assert match.info.album_id == "pseudo"
         assert match.info.album == "In Bloom"
+
+
+class TestMBPseudoPluginCustomTagsOnly(PluginMixin):
+    plugin = "mbpseudo"
+
+    @pytest.fixture(scope="class")
+    def mbpseudo_plugin(self) -> MusicBrainzPseudoReleasePlugin:
+        self.config["import"]["languages"] = ["en", "jp"]
+        self.config[self.plugin]["scripts"] = ["Latn"]
+        self.config[self.plugin]["custom_tags_only"] = True
+        return MusicBrainzPseudoReleasePlugin()
+
+    @pytest.fixture(scope="class")
+    def official_release(self, rsrc_dir: pathlib.Path) -> JSONDict:
+        info_json = (rsrc_dir / "official_release.json").read_text(
+            encoding="utf-8"
+        )
+        return json.loads(info_json)
+
+    @pytest.fixture(scope="class")
+    def pseudo_release(self, rsrc_dir: pathlib.Path) -> JSONDict:
+        info_json = (rsrc_dir / "pseudo_release.json").read_text(
+            encoding="utf-8"
+        )
+        return json.loads(info_json)
+
+    def test_custom_tags(
+        self,
+        mbpseudo_plugin: MusicBrainzPseudoReleasePlugin,
+        official_release: JSONDict,
+        pseudo_release: JSONDict,
+    ):
+        mbpseudo_plugin._release_getter = (
+            lambda album_id, includes: pseudo_release
+        )
+        album_info = mbpseudo_plugin.album_info(official_release["release"])
+        assert not isinstance(album_info, PseudoAlbumInfo)
+        assert album_info.data_source == "MusicBrainzPseudoRelease"
+        assert album_info["album_transl"] == "In Bloom"
+        assert album_info["album_artist_transl"] == "Lilas Ikuta"
+        assert album_info.tracks[0]["title_transl"] == "In Bloom"
+        assert album_info.tracks[0]["artist_transl"] == "Lilas Ikuta"