Ftintitle: Continue even if albumartist and artist is the same (#6102)

## Description

This small PR allows ftintitle to process even if the artist/s in the
artist and albumartist fields are the same.

This fixes the problem with a lot of singles like [Porter Robinsons song
Shelter](https://musicbrainz.org/release/ccc261b9-e4cc-4965-81b8-7c92a5d28601)
and even [Rihanas's album
Umbrella](https://musicbrainz.org/release/60f8f1f5-485b-4637-8574-23f2bb98531f)

Without this fix the songs would end up with the feat. artist in the
artists folder-name and not the feat. in the songs filename.
Without:
`Rihanna feat. JAY‐Z\(2007) Umbrella\01 - Umbrella (radio edit).flac`
`Porter Robinson feat. Madeon\(2016) Shelter\01 - Shelter.flac`
With:
`Rihanna\(2007) Umbrella\01 - Umbrella (radio edit) feat. JAY‐Z.flac`
`Porter Robinson\(2016) Shelter\01 - Shelter feat. Madeon.flac`

I left the current way ftintitle works as the default so stuff doesn't
randomly change for users, but maybe it should is changed as the PR that
changed the ftintitle's behavour is only ~2 month old
https://github.com/beetbox/beets/pull/5943
Thoughts?

I'm also not super happy with the args name
`skip_if_artist_and_album_artists_is_the_same` so any suggestion what it
could be instead is more than welcome 😅


## To Do

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beetsplug/ftintitle.py

@@ -108,6 +108,7 @@ class FtInTitlePlugin(plugins.BeetsPlugin):
                 "drop": False,
                 "format": "feat. {}",
                 "keep_in_artist": False,
+                "preserve_album_artist": True,
                 "custom_words": [],
             }
         )
@@ -133,12 +134,19 @@ class FtInTitlePlugin(plugins.BeetsPlugin):
             self.config.set_args(opts)
             drop_feat = self.config["drop"].get(bool)
             keep_in_artist_field = self.config["keep_in_artist"].get(bool)
+            preserve_album_artist = self.config["preserve_album_artist"].get(
+                bool
+            )
             custom_words = self.config["custom_words"].get(list)
             write = ui.should_write()
 
             for item in lib.items(args):
                 if self.ft_in_title(
-                    item, drop_feat, keep_in_artist_field, custom_words
+                    item,
+                    drop_feat,
+                    keep_in_artist_field,
+                    preserve_album_artist,
+                    custom_words,
                 ):
                     item.store()
                     if write:
@@ -151,11 +159,16 @@ class FtInTitlePlugin(plugins.BeetsPlugin):
         """Import hook for moving featuring artist automatically."""
         drop_feat = self.config["drop"].get(bool)
         keep_in_artist_field = self.config["keep_in_artist"].get(bool)
+        preserve_album_artist = self.config["preserve_album_artist"].get(bool)
         custom_words = self.config["custom_words"].get(list)
 
         for item in task.imported_items():
             if self.ft_in_title(
-                item, drop_feat, keep_in_artist_field, custom_words
+                item,
+                drop_feat,
+                keep_in_artist_field,
+                preserve_album_artist,
+                custom_words,
             ):
                 item.store()
 
@@ -204,6 +217,7 @@ class FtInTitlePlugin(plugins.BeetsPlugin):
         item: Item,
         drop_feat: bool,
         keep_in_artist_field: bool,
+        preserve_album_artist: bool,
         custom_words: list[str],
     ) -> bool:
         """Look for featured artists in the item's artist fields and move
@@ -218,7 +232,7 @@ class FtInTitlePlugin(plugins.BeetsPlugin):
         # Check whether there is a featured artist on this track and the
         # artist field does not exactly match the album artist field. In
         # that case, we attempt to move the featured artist to the title.
-        if albumartist and artist == albumartist:
+        if preserve_album_artist and albumartist and artist == albumartist:
             return False
 
         _, featured = split_on_feat(artist, custom_words=custom_words)

docs/changelog.rst

@@ -10,7 +10,9 @@ Unreleased
 New features:
 
 - :doc:`plugins/ftintitle`: Added argument for custom feat. words in ftintitle.
-- :doc: `/plugins/play`: Added `$playlist` marker to precisely edit the playlist
+- :doc:`plugins/ftintitle`: Added argument to skip the processing of artist and
+  album artist are the same in ftintitle.
+- :doc:`plugins/play`: Added `$playlist` marker to precisely edit the playlist
       filepath into the command calling the player program.
 
 Bug fixes:

docs/plugins/ftintitle.rst

@@ -28,6 +28,8 @@ file. The available options are:
 - **keep_in_artist**: Keep the featuring X part in the artist field. This can be
   useful if you still want to be able to search for features in the artist
   field. Default: ``no``.
+- **preserve_album_artist**: If the artist and the album artist are the same,
+  skip the ftintitle processing. Default: ``yes``.
 - **custom_words**: List of additional words that will be treated as a marker
   for artist features. Default: ``[]``.
 

test/plugins/test_ftintitle.py

@@ -205,6 +205,47 @@ def add_item(
             ("Alice med Bob", "Song 1"),
             id="custom-feat-words-keep-in-artists-drop-from-title",
         ),
+        # ---- preserve_album_artist variants ----
+        pytest.param(
+            {
+                "format": "feat. {}",
+                "preserve_album_artist": True,
+            },
+            ("ftintitle",),
+            ("Alice feat. Bob", "Song 1", "Alice"),
+            ("Alice", "Song 1 feat. Bob"),
+            id="skip-if-artist-and-album-artists-is-the-same-different-match",
+        ),
+        pytest.param(
+            {
+                "format": "feat. {}",
+                "preserve_album_artist": False,
+            },
+            ("ftintitle",),
+            ("Alice feat. Bob", "Song 1", "Alice"),
+            ("Alice", "Song 1 feat. Bob"),
+            id="skip-if-artist-and-album-artists-is-the-same-different-match-b",
+        ),
+        pytest.param(
+            {
+                "format": "feat. {}",
+                "preserve_album_artist": True,
+            },
+            ("ftintitle",),
+            ("Alice feat. Bob", "Song 1", "Alice feat. Bob"),
+            ("Alice feat. Bob", "Song 1"),
+            id="skip-if-artist-and-album-artists-is-the-same-matching-match",
+        ),
+        pytest.param(
+            {
+                "format": "feat. {}",
+                "preserve_album_artist": False,
+            },
+            ("ftintitle",),
+            ("Alice feat. Bob", "Song 1", "Alice feat. Bob"),
+            ("Alice", "Song 1 feat. Bob"),
+            id="skip-if-artist-and-album-artists-is-the-same-matching-match-b",
+        ),
     ],
 )
 def test_ftintitle_functional(