Merge remote-tracking branch 'origin/develop' into rav/saml2_client

1 files changed, 14 insertions, 5 deletions

diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py

index 6209858bbb..557fb5f83d 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -158,7 +158,13 @@ class PresenceHandler(object):
         # have not yet been persisted
         self.unpersisted_users_changes = set()
 
-        hs.get_reactor().addSystemEventTrigger("before", "shutdown", self._on_shutdown)
+        hs.get_reactor().addSystemEventTrigger(
+            "before",
+            "shutdown",
+            run_as_background_process,
+            "presence.on_shutdown",
+            self._on_shutdown,
+        )
 
         self.serial_to_user = {}
         self._next_serial = 1
@@ -828,14 +834,17 @@ class PresenceHandler(object):
                 # joins.
                 continue
 
-            event = yield self.store.get_event(event_id)
-            if event.content.get("membership") != Membership.JOIN:
+            event = yield self.store.get_event(event_id, allow_none=True)
+            if not event or event.content.get("membership") != Membership.JOIN:
                 # We only care about joins
                 continue
 
             if prev_event_id:
-                prev_event = yield self.store.get_event(prev_event_id)
-                if prev_event.content.get("membership") == Membership.JOIN:
+                prev_event = yield self.store.get_event(prev_event_id, allow_none=True)
+                if (
+                    prev_event
+                    and prev_event.content.get("membership") == Membership.JOIN
+                ):
                     # Ignore changes to join events.
                     continue