From 4e5f0f7ca098022b718233d9b429247e6228f31d Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Thu, 28 Mar 2019 13:55:21 +0000
Subject: [PATCH] Use an assert

---
 synapse/handlers/presence.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 4e71e10295..e85c49742d 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -939,8 +939,7 @@ class PresenceHandler(object):
 
         @defer.inlineCallbacks
         def _process_presence():
-            if self._event_processing:
-                return
+            assert not self._event_processing
 
             self._event_processing = True
             try: