From f9d4da7f4502aeefe7a5a6a9ec0d2682458e7834 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Mon, 17 Aug 2015 09:39:12 +0100
Subject: [PATCH] Fix bug where we were leaking None into state event lists

---
 synapse/storage/state.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index 185f88fd7..ecb62e6df 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -412,9 +412,10 @@ class StateStore(SQLBaseStore):
                 full=(types is None),
             )
 
-            results[group].update({
+            # We replace here to remove all the entries with None values.
+            results[group] = {
                 key: value for key, value in state_dict.items() if value
-            })
+            }
 
         defer.returnValue(results)