Experimental support for MSC3772 (#12740)

Implements the following behind an experimental configuration flag:

* A new push rule kind for mutually related events.
* A new default push rule (`.m.rule.thread_reply`) under an unstable prefix.

This is missing part of MSC3772:

* The `.m.rule.thread_reply_to_me` push rule, this depends on MSC3664 / #11804.

1 files changed, 9 insertions, 0 deletions

diff --git a/synapse/storage/databases/main/events.py b/synapse/storage/databases/main/events.py
index 0df8ff5395..17e35cf63e 100644
--- a/synapse/storage/databases/main/events.py
+++ b/synapse/storage/databases/main/events.py
@@ -1828,6 +1828,10 @@ class PersistEventsStore:
             self.store.get_aggregation_groups_for_event.invalidate,
             (relation.parent_id,),
         )
+        txn.call_after(
+            self.store.get_mutual_event_relations_for_rel_type.invalidate,
+            (relation.parent_id,),
+        )
 
         if relation.rel_type == RelationTypes.REPLACE:
             txn.call_after(
@@ -2004,6 +2008,11 @@ class PersistEventsStore:
             self.store._invalidate_cache_and_stream(
                 txn, self.store.get_thread_participated, (redacted_relates_to,)
             )
+            self.store._invalidate_cache_and_stream(
+                txn,
+                self.store.get_mutual_event_relations_for_rel_type,
+                (redacted_relates_to,),
+            )
 
         self.db_pool.simple_delete_txn(
             txn, table="event_relations", keyvalues={"event_id": redacted_event_id}