Draft: Ignore sending events to appservice when they come from our own homeserver

changelog.d/14729.misc

@@ -0,0 +1 @@
+Don't merge this.

synapse/appservice/scheduler.py

@@ -98,6 +98,7 @@ class ApplicationServiceScheduler:
     """
 
     def __init__(self, hs: "HomeServer"):
+        self._hs = hs
         self.clock = hs.get_clock()
         self.store = hs.get_datastores().main
         self.as_api = hs.get_application_service_api()
@@ -148,6 +149,16 @@ def enqueue_for_appservice(
         ):
             return
 
+        if events:
+            # XXX: Special patch just for Gitter which we should remove after the import,
+            # https://github.com/matrix-org/synapse/pull/14729
+            #
+            # Ignore events that come from our own users. We probably already know about
+            # them and sent them ourself.
+            events = [
+                event for event in events if not self._hs.is_mine_id(event.sender)
+            ]
+
         if events:
             self.queuer.queued_events.setdefault(appservice.id, []).extend(events)
         if ephemeral: