Re-enable some linting

pyproject.toml

@@ -48,7 +48,7 @@ line-length = 88
 #  E731: do not assign a lambda expression, use a def
 #  E501: Line too long (black enforces this for us)
 #
-# See https://github.com/charliermarsh/ruff/#pyflakes
+# See https://github.com/charliermarsh/ruff/#pyflakes-f
 #  F401: unused import
 #  F811: Redefinition of unused
 #  F821: Undefined name
@@ -64,9 +64,6 @@ ignore = [
     "B024",
     "E501",
     "E731",
-    "F401",
-    "F811",
-    "F821",
 ]
 select = [
     # pycodestyle checks.
@@ -80,6 +77,10 @@ select = [
     "C4",
 ]
 
+[tool.ruff.per-file-ignores]
+# Ruff is *very* confused about this .pyi file, so let's just ignore it for now.
+"synapse/config/_base.pyi" = ["F401", "F811"]
+
 [tool.isort]
 line_length = 88
 sections = ["FUTURE", "STDLIB", "THIRDPARTY", "TWISTED", "FIRSTPARTY", "TESTS", "LOCALFOLDER"]

stubs/sortedcontainers/sortedlist.pyi

@@ -7,7 +7,6 @@ from __future__ import annotations
 from typing import (
     Any,
     Callable,
-    Generic,
     Iterable,
     Iterator,
     List,

stubs/sortedcontainers/sortedset.pyi

@@ -5,10 +5,8 @@
 from __future__ import annotations
 
 from typing import (
-    AbstractSet,
     Any,
     Callable,
-    Generic,
     Hashable,
     Iterable,
     Iterator,

stubs/synapse/synapse_rust/push.pyi

@@ -1,4 +1,4 @@
-from typing import Any, Collection, Dict, Mapping, Optional, Sequence, Set, Tuple, Union
+from typing import Any, Collection, Dict, Mapping, Optional, Sequence, Tuple, Union
 
 from synapse.types import JsonDict
 

tests/storage/test_event_push_actions.py

@@ -154,7 +154,7 @@ def test_count_aggregation(self) -> None:
         # Create a user to receive notifications and send receipts.
         user_id, token, _, other_token, room_id = self._create_users_and_room()
 
-        last_event_id: str
+        last_event_id = ""
 
         def _assert_counts(notif_count: int, highlight_count: int) -> None:
             counts = self.get_success(
@@ -289,7 +289,7 @@ def test_count_aggregation_threads(self) -> None:
         user_id, token, _, other_token, room_id = self._create_users_and_room()
         thread_id: str
 
-        last_event_id: str
+        last_event_id = ""
 
         def _assert_counts(
             notif_count: int,
@@ -471,7 +471,7 @@ def test_count_aggregation_mixed(self) -> None:
         user_id, token, _, other_token, room_id = self._create_users_and_room()
         thread_id: str
 
-        last_event_id: str
+        last_event_id = ""
 
         def _assert_counts(
             notif_count: int,