Make Filter a Generic.

synapse/api/filtering.py

@@ -19,6 +19,7 @@ from typing import (
     TYPE_CHECKING,
     Awaitable,
     Container,
+    Generic,
     Iterable,
     List,
     Optional,
@@ -186,6 +187,7 @@ class Filtering:
 
 
 # Filters work across events, presence EDUs, and account data.
+FilterRoomEvent = TypeVar("FilterRoomEvent", EventBase, JsonDict)
 FilterEvent = TypeVar("FilterEvent", EventBase, UserPresenceState, JsonDict)
 
 
@@ -195,16 +197,28 @@ class FilterCollection:
 
         room_filter_json = self._filter_json.get("room", {})
 
-        self._room_filter = Filter(
+        self._room_filter: Filter[FilterRoomEvent] = Filter(
             {k: v for k, v in room_filter_json.items() if k in ("rooms", "not_rooms")}
         )
 
-        self._room_timeline_filter = Filter(room_filter_json.get("timeline", {}))
-        self._room_state_filter = Filter(room_filter_json.get("state", {}))
-        self._room_ephemeral_filter = Filter(room_filter_json.get("ephemeral", {}))
-        self._room_account_data = Filter(room_filter_json.get("account_data", {}))
-        self._presence_filter = Filter(filter_json.get("presence", {}))
-        self._account_data = Filter(filter_json.get("account_data", {}))
+        self._room_timeline_filter: Filter[EventBase] = Filter(
+            room_filter_json.get("timeline", {})
+        )
+        self._room_state_filter: Filter[EventBase] = Filter(
+            room_filter_json.get("state", {})
+        )
+        self._room_ephemeral_filter: Filter[JsonDict] = Filter(
+            room_filter_json.get("ephemeral", {})
+        )
+        self._room_account_data: Filter[JsonDict] = Filter(
+            room_filter_json.get("account_data", {})
+        )
+        self._presence_filter: Filter[UserPresenceState] = Filter(
+            filter_json.get("presence", {})
+        )
+        self._account_data: Filter[JsonDict] = Filter(
+            filter_json.get("account_data", {})
+        )
 
         self.include_leave = filter_json.get("room", {}).get("include_leave", False)
         self.event_fields = filter_json.get("event_fields", [])
@@ -272,7 +286,7 @@ class FilterCollection:
         )
 
 
-class Filter:
+class Filter(Generic[FilterEvent]):
     def __init__(self, filter_json: JsonDict):
         self.filter_json = filter_json
 
@@ -406,7 +420,7 @@ class Filter:
     def include_redundant_members(self) -> bool:
         return self.filter_json.get("include_redundant_members", False)
 
-    def with_room_ids(self, room_ids: Iterable[str]) -> "Filter":
+    def with_room_ids(self, room_ids: Iterable[str]) -> "Filter[FilterEvent]":
         """Returns a new filter with the given room IDs appended.
 
         Args:
@@ -416,9 +430,9 @@ class Filter:
             filter: A new filter including the given rooms and the old
                     filter's rooms.
         """
-        newFilter = Filter(self.filter_json)
-        newFilter.rooms += room_ids
-        return newFilter
+        new_filter: Filter[FilterEvent] = Filter(self.filter_json)
+        new_filter.rooms += room_ids
+        return new_filter
 
 
 def _matches_wildcard(actual_value: Optional[str], filter_value: str) -> bool:

synapse/handlers/search.py

@@ -180,7 +180,7 @@ class SearchHandler:
                 % (set(group_keys) - {"room_id", "sender"},),
             )
 
-        search_filter = Filter(filter_dict)
+        search_filter: Filter[EventBase] = Filter(filter_dict)
 
         # TODO: Search through left rooms too
         rooms = await self.store.get_rooms_for_local_user_where_membership_is(