From 34e5e17f916d50027939582f1fd9d399592ba63f Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Fri, 2 Sep 2016 14:26:07 +0100
Subject: [PATCH] Comment

---
 synapse/handlers/federation.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index ca51044ae..2338c3a72 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -118,6 +118,9 @@ class FederationHandler(BaseHandler):
 
         # FIXME (erikj): Awful hack to make the case where we are not currently
         # in the room work
+        # If state and auth_chain are None, then we don't need to do this check
+        # as we already know we have enough state in the DB to handle this
+        # event.
         if state and auth_chain and not event.internal_metadata.is_outlier():
             is_in_room = yield self.auth.check_host_in_room(
                 event.room_id,