Define StateMap as immutable and add a MutableStateMap type. (#8183)

3 files changed, 19 insertions, 9 deletions

diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index f8b234cee2..155d087413 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -72,7 +72,13 @@ from synapse.replication.http.federation import (
 from synapse.replication.http.membership import ReplicationUserJoinedLeftRoomRestServlet
 from synapse.state import StateResolutionStore, resolve_events_with_store
 from synapse.storage.databases.main.events_worker import EventRedactBehaviour
-from synapse.types import JsonDict, StateMap, UserID, get_domain_from_id
+from synapse.types import (
+    JsonDict,
+    MutableStateMap,
+    StateMap,
+    UserID,
+    get_domain_from_id,
+)
 from synapse.util.async_helpers import Linearizer, concurrently_execute
 from synapse.util.distributor import user_joined_room
 from synapse.util.retryutils import NotRetryingDestination
@@ -96,7 +102,7 @@ class _NewEventInfo:
 
     event = attr.ib(type=EventBase)
     state = attr.ib(type=Optional[Sequence[EventBase]], default=None)
-    auth_events = attr.ib(type=Optional[StateMap[EventBase]], default=None)
+    auth_events = attr.ib(type=Optional[MutableStateMap[EventBase]], default=None)
 
 
 class FederationHandler(BaseHandler):
@@ -2053,7 +2059,7 @@ class FederationHandler(BaseHandler):
         origin: str,
         event: EventBase,
         state: Optional[Iterable[EventBase]],
-        auth_events: Optional[StateMap[EventBase]],
+        auth_events: Optional[MutableStateMap[EventBase]],
         backfilled: bool,
     ) -> EventContext:
         context = await self.state_handler.compute_event_context(event, old_state=state)
@@ -2137,7 +2143,9 @@ class FederationHandler(BaseHandler):
             current_states = await self.state_handler.resolve_events(
                 room_version, state_sets, event
             )
-            current_state_ids = {k: e.event_id for k, e in current_states.items()}
+            current_state_ids = {
+                k: e.event_id for k, e in current_states.items()
+            }  # type: StateMap[str]
         else:
             current_state_ids = await self.state_handler.get_current_state_ids(
                 event.room_id, latest_event_ids=extrem_ids
@@ -2223,7 +2231,7 @@ class FederationHandler(BaseHandler):
         origin: str,
         event: EventBase,
         context: EventContext,
-        auth_events: StateMap[EventBase],
+        auth_events: MutableStateMap[EventBase],
     ) -> EventContext:
         """
 
@@ -2274,7 +2282,7 @@ class FederationHandler(BaseHandler):
         origin: str,
         event: EventBase,
         context: EventContext,
-        auth_events: StateMap[EventBase],
+        auth_events: MutableStateMap[EventBase],
     ) -> EventContext:
         """Helper for do_auth. See there for docs.
 
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 236a37f777..1419d72e94 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -41,6 +41,7 @@ from synapse.http.endpoint import parse_and_validate_server_name
 from synapse.storage.state import StateFilter
 from synapse.types import (
     JsonDict,
+    MutableStateMap,
     Requester,
     RoomAlias,
     RoomID,
@@ -814,7 +815,7 @@ class RoomCreationHandler(BaseHandler):
         room_id: str,
         preset_config: str,
         invite_list: List[str],
-        initial_state: StateMap,
+        initial_state: MutableStateMap,
         creation_content: JsonDict,
         room_alias: Optional[RoomAlias] = None,
         power_level_content_override: Optional[JsonDict] = None,
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index c42dac18f5..9a86eb01c9 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -31,6 +31,7 @@ from synapse.storage.state import StateFilter
 from synapse.types import (
     Collection,
     JsonDict,
+    MutableStateMap,
     RoomStreamToken,
     StateMap,
     StreamToken,
@@ -588,7 +589,7 @@ class SyncHandler(object):
         room_id: str,
         sync_config: SyncConfig,
         batch: TimelineBatch,
-        state: StateMap[EventBase],
+        state: MutableStateMap[EventBase],
         now_token: StreamToken,
     ) -> Optional[JsonDict]:
         """ Works out a room summary block for this room, summarising the number
@@ -736,7 +737,7 @@ class SyncHandler(object):
         since_token: Optional[StreamToken],
         now_token: StreamToken,
         full_state: bool,
-    ) -> StateMap[EventBase]:
+    ) -> MutableStateMap[EventBase]:
         """ Works out the difference in state between the start of the timeline
         and the previous sync.