Refactor to include inviter_user_id as part of stripped state

See:

 - https://github.com/element-hq/synapse/pull/19723#discussion_r3318830203
 - https://github.com/matrix-org/sytest/pull/1425#discussion_r3319446010

synapse/federation/federation_client.py

@@ -144,7 +144,6 @@ class FederationClient(FederationBase):
 
         self.server_name = hs.hostname
         self.signing_key = hs.signing_key
-        self._room_prejoin_state_types = hs.config.api.room_prejoin_state
 
         # Cache mapping `event_id` to a tuple of the event itself and the `pull_origin`
         # (which server we pulled the event from)
@@ -1367,7 +1366,8 @@ class FederationClient(FederationBase):
         #
         # Find the full events based on the state at the time of the invite
         state_ids = await self.store.get_stripped_room_state_ids_from_event_context(
-            context, self._room_prejoin_state_types
+            context,
+            self.store.calculate_stripped_state_filter(inviter_user_id=pdu.sender),
         )
         state_events = await self.store.get_events(state_ids)
         assert set(state_ids) == set(state_events.keys()), (

synapse/federation/federation_server.py

@@ -194,8 +194,6 @@ class FederationServer(FederationBase):
             hs.config.federation.federation_metrics_domains
         )
 
-        self._room_prejoin_state_types = hs.config.api.room_prejoin_state
-
         # Whether we have started handling old events in the staging area.
         self._started_handling_of_staged_events = False
 
@@ -1031,7 +1029,11 @@ class FederationServer(FederationBase):
         #
         # Find the full events based on the state at the time of the knock
         state_ids = await self.store.get_stripped_room_state_ids_from_event_context(
-            context, self._room_prejoin_state_types
+            context,
+            self.store.calculate_stripped_state_filter(
+                # None as this is a knock, not an invite
+                inviter_user_id=None
+            ),
         )
         state_events = await self.store.get_events(state_ids)
         assert set(state_ids) == set(state_events.keys()), (

synapse/handlers/message.py

@@ -509,8 +509,6 @@ class EventCreationHandler:
         self._worker_lock_handler = hs.get_worker_locks_handler()
         self._policy_handler = hs.get_room_policy_handler()
 
-        self.room_prejoin_state_types = self.hs.config.api.room_prejoin_state
-
         self.send_events = ReplicationSendEventsRestServlet.make_client(hs)
 
         self.request_ratelimiter = hs.get_request_ratelimiter()
@@ -2079,8 +2077,9 @@ class EventCreationHandler:
                         "invite_room_state",
                         await self.store.get_stripped_room_state_from_event_context(
                             context,
-                            self.room_prejoin_state_types,
-                            membership_user_id=event.sender,
+                            self.store.calculate_stripped_state_filter(
+                                inviter_user_id=event.sender
+                            ),
                         ),
                     )
 
@@ -2104,7 +2103,10 @@ class EventCreationHandler:
                         "knock_room_state",
                         await self.store.get_stripped_room_state_from_event_context(
                             context,
-                            self.room_prejoin_state_types,
+                            self.store.calculate_stripped_state_filter(
+                                # None as this is a knock, not an invite
+                                inviter_user_id=None
+                            ),
                         ),
                     )
 

synapse/storage/databases/main/events_worker.py

@@ -385,6 +385,8 @@ class EventsWorkerStore(SQLBaseStore):
         finished (so we don't have to keep querying it every time)
         """
 
+        self._room_prejoin_state_types = hs.config.api.room_prejoin_state
+
     def get_un_partial_stated_events_token(self, instance_name: str) -> int:
         return (
             self._un_partial_stated_events_stream_id_gen.get_current_token_for_writer(
@@ -1125,16 +1127,42 @@ class EventsWorkerStore(SQLBaseStore):
 
         return event_map
 
+    def calculate_stripped_state_filter(
+        self,
+        *,
+        inviter_user_id: str | None = None,
+    ) -> StateFilter:
+        """
+        Calculate the stripped state filter necessary for an event
+
+        Args:
+            inviter_user_id: An optional user ID to include the stripped membership state
+                events of. This is useful when generating the stripped state of a room for
+                invites. We want to send membership events of the inviter, so that the
+                invitee can display the inviter's profile information if the room lacks any.
+        """
+        state_filter = self._room_prejoin_state_types
+
+        # Include the state for `inviter_user_id` if specified
+        #
+        # FIXME: Doesn't seem to be in the spec
+        if inviter_user_id:
+            types = chain(
+                self._room_prejoin_state_types.to_types(),
+                [(EventTypes.Member, inviter_user_id)],
+            )
+            state_filter = StateFilter.from_types(types)
+
+        return state_filter
+
     async def get_stripped_room_state_from_event_context(
         self,
         context: EventContext,
         state_keys_to_include: StateFilter,
-        membership_user_id: str | None = None,
     ) -> list[JsonDict]:
         """
         Retrieve the stripped state from a room, given an event context to retrieve state
-        from as well as the state types to include. Optionally, include the membership
-        events from a specific user.
+        from as well as the state types to include.
 
         "Stripped" state means that only the `type`, `state_key`, `content` and `sender` keys
         are included from each state event.
@@ -1142,25 +1170,13 @@ class EventsWorkerStore(SQLBaseStore):
         Args:
             context: The event context to retrieve state of the room from.
             state_keys_to_include: The state events to include, for each event type.
-            membership_user_id: An optional user ID to include the stripped membership state
-                events of. This is useful when generating the stripped state of a room for
-                invites. We want to send membership events of the inviter, so that the
-                invitee can display the inviter's profile information if the room lacks any.
 
         Returns:
             A list of dictionaries, each representing a stripped state event from the room.
         """
-        if membership_user_id:
-            types = chain(
-                state_keys_to_include.to_types(),
-                [(EventTypes.Member, membership_user_id)],
-            )
-            filter = StateFilter.from_types(types)
-        else:
-            filter = state_keys_to_include
 
         selected_state_ids = await self.get_stripped_room_state_ids_from_event_context(
-            context, filter
+            context, state_keys_to_include
         )
 
         state_to_include = await self.get_events(selected_state_ids)
@@ -1174,8 +1190,7 @@ class EventsWorkerStore(SQLBaseStore):
     ) -> list[str]:
         """
         Retrieve the stripped state IDs for an event, given an event context to retrieve state
-        from as well as the state types to include. Optionally, include the membership
-        events from a specific user.
+        from as well as the state types to include.
 
         "Stripped" state means that only the `type`, `state_key`, `content` and `sender` keys
         are included from each state event.