Add a sync flag for unread thread notifications

synapse/api/filtering.py

@@ -84,6 +84,7 @@
         "contains_url": {"type": "boolean"},
         "lazy_load_members": {"type": "boolean"},
         "include_redundant_members": {"type": "boolean"},
+        "unread_thread_notifications": {"type": "boolean"},
         # Include or exclude events with the provided labels.
         # cf https://github.com/matrix-org/matrix-doc/pull/2326
         "org.matrix.labels": {"type": "array", "items": {"type": "string"}},
@@ -240,6 +241,9 @@ def lazy_load_members(self) -> bool:
     def include_redundant_members(self) -> bool:
         return self._room_state_filter.include_redundant_members
 
+    def unread_thread_notifications(self) -> bool:
+        return self._room_timeline_filter.unread_thread_notifications
+
     async def filter_presence(
         self, events: Iterable[UserPresenceState]
     ) -> List[UserPresenceState]:
@@ -304,6 +308,9 @@ def __init__(self, hs: "HomeServer", filter_json: JsonDict):
         self.include_redundant_members = filter_json.get(
             "include_redundant_members", False
         )
+        self.unread_thread_notifications = filter_json.get(
+            "unread_thread_notifications", False
+        )
 
         self.types = filter_json.get("types", None)
         self.not_types = filter_json.get("not_types", [])

synapse/handlers/sync.py

@@ -2133,8 +2133,11 @@ async def _generate_room_entry(
                     highlight_count = notifs.highlight_count
                     unread_count = notifs.unread_count
 
-                    # XXX Check the sync configuration.
-                    if self._msc3773_enabled:
+                    # Check the sync configuration.
+                    if (
+                        self._msc3773_enabled
+                        and sync_config.filter_collection.unread_thread_notifications()
+                    ):
                         # And add info for each thread.
                         room_sync.unread_thread_notifications = {
                             thread_id: {