From 608b5a6317ce3797ff279f6d1a8a39f475b55736 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 16 May 2017 12:55:29 +0100
Subject: [PATCH] Take a copy before prefilling, as it may be a frozendict

---
 synapse/storage/state.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index 03981f5d2..85acf2ad1 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -235,7 +235,7 @@ class StateStore(SQLBaseStore):
                 self._state_group_cache.update,
                 self._state_group_cache.sequence,
                 key=context.state_group,
-                value=context.current_state_ids,
+                value=dict(context.current_state_ids),
                 full=True,
             )