From e9877c87fe73da8e5cf89a732551126ee93f30eb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Sommer?= <joerg@jo-so.de>
Date: Sat, 9 Mar 2019 07:25:18 +0100
Subject: [PATCH] handler/sync: Handle batches without events

Check if the batch contains events before trying to access them.

Fixes #4842
---
 synapse/handlers/sync.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 57bb996245d5..4290c930a3f3 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -770,7 +770,7 @@ def compute_state_delta(self, room_id, batch, sync_config, since_token, now_toke
                     current=current_state_ids,
                     lazy_load_members=lazy_load_members,
                 )
-            elif batch.limited:
+            elif batch.limited and batch.events:
                 state_at_timeline_start = yield self.store.get_state_ids_for_event(
                     batch.events[0].event_id, state_filter=state_filter,
                 )