Check databases/__init__ and main/cache with mypy. (#15496)

changelog.d/15496.misc

@@ -0,0 +1 @@
+Improve type hints.

mypy.ini

@@ -28,13 +28,10 @@ files =
 # https://docs.python.org/3/library/re.html#re.X
 exclude = (?x)
   ^(
-   |synapse/storage/databases/__init__.py
-   |synapse/storage/databases/main/cache.py
    |synapse/storage/schema/
    )$
 
 [mypy-synapse.metrics._reactor_metrics]
-disallow_untyped_defs = False
 # This module imports select.epoll. That exists on Linux, but doesn't on macOS.
 # See https://github.com/matrix-org/synapse/pull/11771.
 warn_unused_ignores = False

synapse/storage/databases/__init__.py

@@ -95,7 +95,7 @@ def __init__(self, main_store_class: Type[DataStoreT], hs: "HomeServer"):
                     # If we're on a process that can persist events also
                     # instantiate a `PersistEventsStore`
                     if hs.get_instance_name() in hs.config.worker.writers.events:
-                        persist_events = PersistEventsStore(hs, database, main, db_conn)
+                        persist_events = PersistEventsStore(hs, database, main, db_conn)  # type: ignore[arg-type]
 
                 if "state" in database_config.databases:
                     logger.info(
@@ -133,6 +133,6 @@ def __init__(self, main_store_class: Type[DataStoreT], hs: "HomeServer"):
 
         # We use local variables here to ensure that the databases do not have
         # optional types.
-        self.main = main
+        self.main = main  # type: ignore[assignment]
         self.state = state
         self.persist_events = persist_events

synapse/storage/databases/main/cache.py

@@ -205,13 +205,13 @@ def _process_event_stream_row(self, token: int, row: EventsStreamRow) -> None:
             )
         elif row.type == EventsStreamCurrentStateRow.TypeId:
             assert isinstance(data, EventsStreamCurrentStateRow)
-            self._curr_state_delta_stream_cache.entity_has_changed(data.room_id, token)
+            self._curr_state_delta_stream_cache.entity_has_changed(data.room_id, token)  # type: ignore[attr-defined]
 
             if data.type == EventTypes.Member:
-                self.get_rooms_for_user_with_stream_ordering.invalidate(
+                self.get_rooms_for_user_with_stream_ordering.invalidate(  # type: ignore[attr-defined]
                     (data.state_key,)
                 )
-                self.get_rooms_for_user.invalidate((data.state_key,))
+                self.get_rooms_for_user.invalidate((data.state_key,))  # type: ignore[attr-defined]
         else:
             raise Exception("Unknown events stream row type %s" % (row.type,))
 
@@ -229,7 +229,7 @@ def _invalidate_caches_for_event(
         # This invalidates any local in-memory cached event objects, the original
         # process triggering the invalidation is responsible for clearing any external
         # cached objects.
-        self._invalidate_local_get_event_cache(event_id)
+        self._invalidate_local_get_event_cache(event_id)  # type: ignore[attr-defined]
 
         self._attempt_to_invalidate_cache("have_seen_event", (room_id, event_id))
         self._attempt_to_invalidate_cache("get_latest_event_ids_in_room", (room_id,))
@@ -242,10 +242,10 @@ def _invalidate_caches_for_event(
         self._attempt_to_invalidate_cache("_get_membership_from_event_id", (event_id,))
 
         if not backfilled:
-            self._events_stream_cache.entity_has_changed(room_id, stream_ordering)
+            self._events_stream_cache.entity_has_changed(room_id, stream_ordering)  # type: ignore[attr-defined]
 
         if redacts:
-            self._invalidate_local_get_event_cache(redacts)
+            self._invalidate_local_get_event_cache(redacts)  # type: ignore[attr-defined]
             # Caches which might leak edits must be invalidated for the event being
             # redacted.
             self._attempt_to_invalidate_cache("get_relations_for_event", (redacts,))
@@ -254,7 +254,7 @@ def _invalidate_caches_for_event(
             self._attempt_to_invalidate_cache("get_thread_id_for_receipts", (redacts,))
 
         if etype == EventTypes.Member:
-            self._membership_stream_cache.entity_has_changed(state_key, stream_ordering)
+            self._membership_stream_cache.entity_has_changed(state_key, stream_ordering)  # type: ignore[attr-defined]
             self._attempt_to_invalidate_cache(
                 "get_invited_rooms_for_local_user", (state_key,)
             )
@@ -378,6 +378,8 @@ def _send_invalidation_to_replication(
             )
 
         if isinstance(self.database_engine, PostgresEngine):
+            assert self._cache_id_gen is not None
+
             # get_next() returns a context manager which is designed to wrap
             # the transaction. However, we want to only get an ID when we want
             # to use it, here, so we need to call __enter__ manually, and have