Raise an error if an authorising user cannot be found.

Author: clokep

synapse/handlers/event_auth.py

@@ -20,7 +20,7 @@
     Membership,
     RestrictedJoinRuleTypes,
 )
-from synapse.api.errors import AuthError
+from synapse.api.errors import AuthError, SynapseError
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersion
 from synapse.events import EventBase
 from synapse.events.builder import EventBuilder
@@ -92,7 +92,7 @@ def compute_auth_events(
 
     async def get_user_which_could_invite(
         self, room_id: str, current_state_ids: StateMap[str]
-    ) -> Optional[str]:
+    ) -> str:
         """
         Searches the room state for a local user who has the power level necessary
         to invite other users.
@@ -132,8 +132,8 @@ async def get_user_which_could_invite(
         if chosen_user:
             return chosen_user
 
-        # TODO What to do if no user is found?
-        return None
+        # No user was found.
+        raise SynapseError(400, "Unable to find a user which could issue an invite")
 
     async def check_host_in_room(self, room_id: str, host: str) -> bool:
         with Measure(self._clock, "check_host_in_room"):

synapse/handlers/federation.py

@@ -1715,18 +1715,12 @@ async def on_make_join_request(
                     )
 
                 if include_auth_user_id:
-                    authorised_user_id = (
-                        await self._event_auth_handler.get_user_which_could_invite(
-                            room_id,
-                            state_ids,
-                        )
+                    event_content[
+                        "join_authorised_via_users_server"
+                    ] = await self._event_auth_handler.get_user_which_could_invite(
+                        room_id,
+                        state_ids,
                     )
-                    if authorised_user_id:
-                        event_content[
-                            "join_authorised_via_users_server"
-                        ] = authorised_user_id
-
-                    # TODO What if there's no authorised user?
 
         builder = self.event_builder_factory.new(
             room_version.identifier,

synapse/handlers/room_member.py

@@ -916,13 +916,12 @@ async def _should_perform_remote_join(
         # If this is going to be a local join, additional information must
         # be included in the event content in order to efficiently validate
         # the event.
-        authorised_user_id = await self.event_auth_handler.get_user_which_could_invite(
+        content[
+            "join_authorised_via_users_server"
+        ] = await self.event_auth_handler.get_user_which_could_invite(
             room_id,
             current_state_ids,
         )
-        if authorised_user_id:
-            content["join_authorised_via_users_server"] = authorised_user_id
-        # TODO If no authorised user is found then something bad happened.
 
         return False, []