From 7c371834ccbdf33f7070981bf23cbf11d1c1c333 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Thu, 1 Mar 2018 16:40:27 +0000
Subject: [PATCH] Stub out broken function only used for cache

---
 synapse/storage/signatures.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/synapse/storage/signatures.py b/synapse/storage/signatures.py
index e6eeb1b641..9e6eaaa532 100644
--- a/synapse/storage/signatures.py
+++ b/synapse/storage/signatures.py
@@ -25,7 +25,9 @@ from synapse.util.caches.descriptors import cached, cachedList
 class SignatureWorkerStore(SQLBaseStore):
     @cached()
     def get_event_reference_hash(self, event_id):
-        return self._get_event_reference_hashes_txn(event_id)
+        # This is a dummy function to allow get_event_reference_hashes
+        # to use its cache
+        raise NotImplementedError()
 
     @cachedList(cached_method_name="get_event_reference_hash",
                 list_name="event_ids", num_args=1)