fix(modify): parse typed values when selecting objects at the confirmation prompt

beets/ui/commands/modify.py

@@ -26,15 +26,18 @@ def modify_items(lib, mods, dels, query, write, move, album, confirm, inherit):
     # objects.
     ui.print_(f"Modifying {len(objs)} {'album' if album else 'item'}s.")
     changed = []
-    templates = {
-        key: functemplate.template(value) for key, value in mods.items()
-    }
-    for obj in objs:
-        obj_mods = {
+    templates = {key: functemplate.template(value) for key, value in mods.items()}
+
+    def parse_mods(obj):
+        # Parse the raw assignment strings into properly typed values for the
+        # given object (e.g. dates into timestamps).
+        return {
             key: model_cls._parse(key, obj.evaluate_template(templates[key]))
             for key in mods.keys()
         }
-        if print_and_modify(obj, obj_mods, dels) and obj not in changed:
+
+    for obj in objs:
+        if print_and_modify(obj, parse_mods(obj), dels) and obj not in changed:
             changed.append(obj)
 
     # Still something to do?
@@ -56,7 +59,7 @@ def modify_items(lib, mods, dels, query, write, move, album, confirm, inherit):
         changed = ui.input_select_objects(
             f"Really modify{extra}",
             changed,
-            lambda o: print_and_modify(o, mods, dels),
+            lambda o: print_and_modify(o, parse_mods(o), dels),
         )
 
     # Apply changes to database and files
@@ -121,9 +124,7 @@ def modify_func(lib, opts, args):
     )
 
 
-modify_cmd = ui.Subcommand(
-    "modify", help="change metadata fields", aliases=("mod",)
-)
+modify_cmd = ui.Subcommand("modify", help="change metadata fields", aliases=("mod",))
 modify_cmd.parser.add_option(
     "-m",
     "--move",

docs/changelog.rst

@@ -34,6 +34,9 @@ Bug fixes
   example a multi-disc album whose cover lives in the album root rather than a
   per-disc directory); the missing art is skipped instead. :bug:`4692`
 - :doc:`plugins/tidal`: Normalize Tidal album types to lowercase.
+- ``modify``: Fix a crash when choosing ``select`` at the confirmation prompt
+  while modifying a non-string field such as ``added``; the per-object value is
+  now parsed before being applied. :bug:`4880`
 
 ..
     For plugin developers

test/ui/commands/test_modify.py

@@ -108,11 +108,17 @@
         assert len(list(original_items)) == 3
         assert len(list(new_items)) == 7
 
+    def test_selective_modify_typed_field(self):
+        # Regression test for a crash when selecting individual objects to
+        # modify a non-string (here date) field: the confirmation callback
+        # used to re-apply the raw string instead of the parsed value.
+        self.modify_inp(["s", "y"], "added=2002-06-03 00:00:00")
+        item = self.lib.items().get()
+        assert item.added == pytest.approx(1023062400, abs=24 * 60 * 60)
+
     def test_modify_formatted(self):
         for i in range(3):
-            self.add_item_fixture(
-                title=f"title{i}", artist="artist", album="album"
-            )
+            self.add_item_fixture(title=f"title{i}", artist="artist", album="album")
         items = list(self.lib.items())
         self.modify("title=${title} - append")
         for item in items:
@@ -162,16 +168,15 @@
         self.modify("--album", "artists=Charli XCX")
         for item in self.lib.items():
             assert item.artists == ["Charli XCX"], (
-                f"artists should be a list with one element, "
-                f"got {item.artists!r}"
+                f"artists should be a list with one element, " f"got {item.artists!r}"
             )
 
     def test_album_modify_genres_not_split(self):
         self.modify("--album", "genres=Rock")
         for item in self.lib.items():
-            assert item.genres == ["Rock"], (
-                f"genres should be a list with one element, got {item.genres!r}"
-            )
+            assert item.genres == [
+                "Rock"
+            ], f"genres should be a list with one element, got {item.genres!r}"
 
     # Misc
 
@@ -217,9 +222,7 @@
         assert mods == {"title": "newTitle"}
 
     def test_arg_parsing_delete(self):
-        query, _, dels = modify_parse_args(
-            ["title:oldTitle", "title!"], is_album=False
-        )
+        query, _, dels = modify_parse_args(["title:oldTitle", "title!"], is_album=False)
         assert query == ["title:oldTitle"]
         assert dels == ["title"]