From 5ade977d0836a9d7615b4e8cc578c48a26198ee8 Mon Sep 17 00:00:00 2001
From: Jorik Schellekens <joriks@matrix.org>
Date: Thu, 5 Sep 2019 15:06:13 +0100
Subject: [PATCH] Opentracing context cannot be none

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

diff --git a/synapse/storage/devices.py b/synapse/storage/devices.py
index 41f62828b..79a58df59 100644
--- a/synapse/storage/devices.py
+++ b/synapse/storage/devices.py
@@ -856,7 +856,7 @@ class DeviceStore(DeviceWorkerStore, BackgroundUpdateStore):
                     "ts": now,
                     "opentracing_context": json.dumps(context)
                     if whitelisted_homeserver(destination)
-                    else None,
+                    else "{}",
                 }
                 for destination in hosts
                 for device_id in device_ids