Don’t update relative symlinks unnecessarily

CHANGELOG.md

@@ -1,6 +1,10 @@
 Change Log
 ==========
 
+## Upcominfg
+* Fix an issue where items in a symlink collection with relative links were
+  always unnecessarily updated.
+
 ## v0.11.1 - 2024-04-24
 * Add `--all` flag to update command which will update all configured
   collections.

beetsplug/alternatives.py

@@ -420,10 +420,18 @@ def item_change_actions(self, item: Item, path: bytes, dest: bytes):
         external collection, but might require metadata updates.
         """
 
-        if path != dest or not util.samefile(os.readlink(path), item.path):
+        if path != dest:
             return [Action.MOVE]
-        else:
+
+        try:
+            link_target_correct = os.path.samefile(path, item.path)
+        except FileNotFoundError:
+            link_target_correct = False
+
+        if link_target_correct:
             return []
+        else:
+            return [Action.MOVE]
 
     @override
     def update(self, create=None):

test/cli_test.py

@@ -117,61 +117,47 @@ def _symlink_view(self):
         }
         self.alt_config = self.config["alternatives"]["by-year"]
 
-    def test_add_move_remove_album(self, absolute=True):
-        """Test the symlinks are created and deleted
-        * An album is added
-        * The path of the alternative collection is changed
-        * The query of the alternative collection is changed such that the
-          album does not match it anymore.
-        * The links are absolute
-        """
+    def _test_add_move_remove_album(self, *, absolute: bool):
+        """Test that symlinks are created, moved and deleted."""
+
         self.add_album(
             artist="Michael Jackson",
             album="Thriller",
             year="1990",
             original_year="1982",
         )
 
+        # Symlink is created
         self.runcli("alt", "update", "by-year")
+        alt_path = self.libdir / "by-year/1990/Thriller/track 1.mp3"
+        library_path = self.libdir / "Michael Jackson/Thriller/track 1.mp3"
+        assert_symlink(alt_path, library_path, absolute)
 
-        by_year_path = self.libdir / "by-year/1990/Thriller/track 1.mp3"
-        target_path = self.libdir / "Michael Jackson/Thriller/track 1.mp3"
-        assert_symlink(by_year_path, target_path, absolute)
+        # Alternative is not updated
+        assert self.runcli("alt", "update", "by-year") == ""
 
+        # Symlink location is updated when path config changes
         self.alt_config["paths"]["default"] = "$original_year/$album/$title"
         self.runcli("alt", "update", "by-year")
+        alt_path = self.libdir / "by-year/1982/Thriller/track 1.mp3"
+        assert_symlink(alt_path, library_path, absolute)
 
-        by_orig_year_path = self.libdir / "by-year/1982/Thriller/track 1.mp3"
-        assert_symlink(by_orig_year_path, target_path, absolute)
-
+        # Symlink is removed
         self.alt_config["query"] = "some_field::foobar"
         self.runcli("alt", "update", "by-year")
-
-        assert_is_not_file(by_orig_year_path)
+        assert_is_not_file(alt_path)
 
     def test_add_move_remove_album_absolute(self):
-        """Test the absolute symlinks are created and deleted
-        * Config link type is absolute
-        * An album is added
-        * The path of the alternative collection is changed
-        * The query of the alternative collection is changed such that the
-          album does not match it anymore.
-        * The links are absolute
-        """
+        """Test that absolute symlinks are created, moved and deleted."""
+
         self.alt_config["link_type"] = "absolute"
-        self.test_add_move_remove_album(absolute=True)
+        self._test_add_move_remove_album(absolute=True)
 
     def test_add_move_remove_album_relative(self):
-        """Test the relative symlinks are created and deleted
-        * Config link type is relative
-        * An album is added
-        * The path of the alternative collection is changed
-        * The query of the alternative collection is changed such that the
-          album does not match it anymore.
-        * The links are relative
-        """
+        """Test that relative symlinks are created, moved and deleted."""
+
         self.alt_config["link_type"] = "relative"
-        self.test_add_move_remove_album(absolute=False)
+        self._test_add_move_remove_album(absolute=False)
 
     def test_update_link_target(self, tmp_path: Path):
         """Link targets are updated when the item has moved in the library"""
@@ -187,11 +173,15 @@ def test_update_link_target(self, tmp_path: Path):
             absolute=True,
         )
 
+        # Moving a library item breaks the symlink
         new_libdir = tmp_path / "newlib"
         new_libdir.mkdir()
         self.runcli("move", "-a", "-d", str(new_libdir), "Thriller")
-        self.runcli("alt", "update", "by-year")
+        assert alt_path.is_symlink()
+        assert not alt_path.is_file()
 
+        # Updating the alternative fixes the symlink
+        self.runcli("alt", "update", "by-year")
         assert_symlink(
             link=alt_path,
             target=new_libdir / "Michael Jackson/Thriller/track 1.mp3",