Do work in parellel when joining a room

synapse/handlers/federation.py

@@ -516,30 +516,59 @@ class FederationHandler(BaseHandler):
                 # FIXME
                 pass
 
-            for e in auth_chain:
-                e.internal_metadata.outlier = True
+            auth_ids_to_deferred = {}
 
-                if e.event_id == event.event_id:
-                    continue
+            def process_auth_ev(ev):
+                auth_ids = [e_id for e_id, _ in ev.auth_events]
+
+                prev_ds = [
+                    auth_ids_to_deferred[i]
+                    for i in auth_ids
+                    if i in auth_ids_to_deferred
+                ]
+
+                d = defer.Deferred()
+
+                auth_ids_to_deferred[ev.event_id] = d
+
+                @defer.inlineCallbacks
+                def f(*_):
+                    ev.internal_metadata.outlier = True
 
                     try:
-                    auth_ids = [e_id for e_id, _ in e.auth_events]
                         auth = {
                             (e.type, e.state_key): e for e in auth_chain
                             if e.event_id in auth_ids
                         }
+
                         yield self._handle_new_event(
-                        origin, e, auth_events=auth
+                            origin, ev, auth_events=auth
                         )
                     except:
                         logger.exception(
                             "Failed to handle auth event %s",
-                        e.event_id,
+                            ev.event_id,
                         )
 
-            for e in state:
+                    d.callback(None)
+
+                if prev_ds:
+                    dx = defer.DeferredList(prev_ds)
+                    dx.addBoth(f)
+                else:
+                    f()
+
+            for e in auth_chain:
                 if e.event_id == event.event_id:
-                    continue
+                    return
+                process_auth_ev(e)
+
+            yield defer.DeferredList(auth_ids_to_deferred.values())
+
+            @defer.inlineCallbacks
+            def handle_state(e):
+                if e.event_id == event.event_id:
+                    return
 
                 e.internal_metadata.outlier = True
                 try:
@@ -557,6 +586,8 @@ class FederationHandler(BaseHandler):
                         e.event_id,
                     )
 
+            yield defer.DeferredList([handle_state(e) for e in state])
+
             auth_ids = [e_id for e_id, _ in event.auth_events]
             auth_events = {
                 (e.type, e.state_key): e for e in auth_chain