Do not add groups to sync results if disabled. (#12408)

changelog.d/12408.misc

@@ -0,0 +1 @@
+Do not include groups in the sync response when disabled.

synapse/handlers/sync.py

@@ -1155,8 +1155,9 @@ async def generate_sync_result(
                 await self.store.get_e2e_unused_fallback_key_types(user_id, device_id)
             )
 
-        logger.debug("Fetching group data")
-        await self._generate_sync_entry_for_groups(sync_result_builder)
+        if self.hs_config.experimental.groups_enabled:
+            logger.debug("Fetching group data")
+            await self._generate_sync_entry_for_groups(sync_result_builder)
 
         num_events = 0
 

synapse/rest/client/sync.py

@@ -301,14 +301,13 @@ async def encode_response(
         if archived:
             response["rooms"][Membership.LEAVE] = archived
 
-        # By the time we get here groups is no longer optional.
-        assert sync_result.groups is not None
-        if sync_result.groups.join:
-            response["groups"][Membership.JOIN] = sync_result.groups.join
-        if sync_result.groups.invite:
-            response["groups"][Membership.INVITE] = sync_result.groups.invite
-        if sync_result.groups.leave:
-            response["groups"][Membership.LEAVE] = sync_result.groups.leave
+        if sync_result.groups is not None:
+            if sync_result.groups.join:
+                response["groups"][Membership.JOIN] = sync_result.groups.join
+            if sync_result.groups.invite:
+                response["groups"][Membership.INVITE] = sync_result.groups.invite
+            if sync_result.groups.leave:
+                response["groups"][Membership.LEAVE] = sync_result.groups.leave
 
         return response