Fix stuck invites

If rejecting a remote invite fails with an error response don't fail
the entire request; instead mark the invite as locally rejected.

This fixes the bug where users can get stuck invites which they can
neither accept nor reject.

2 files changed, 37 insertions, 15 deletions

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

index 4049c01d26..19769eecd7 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -784,13 +784,19 @@ class FederationHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def do_remotely_reject_invite(self, target_hosts, room_id, user_id):
-        origin, event = yield self._make_and_verify_event(
-            target_hosts,
-            room_id,
-            user_id,
-            "leave"
-        )
-        signed_event = self._sign_event(event)
+        try:
+            origin, event = yield self._make_and_verify_event(
+                target_hosts,
+                room_id,
+                user_id,
+                "leave"
+            )
+            signed_event = self._sign_event(event)
+        except SynapseError:
+            raise
+        except CodeMessageException as e:
+            logger.warn("Failed to reject invite: %s", e)
+            raise SynapseError(500, "Failed to reject invite")
 
         # Try the host we successfully got a response to /make_join/
         # request first.
@@ -800,10 +806,16 @@ class FederationHandler(BaseHandler):
         except ValueError:
             pass
 
-        yield self.replication_layer.send_leave(
-            target_hosts,
-            signed_event
-        )
+        try:
+            yield self.replication_layer.send_leave(
+                target_hosts,
+                signed_event
+            )
+        except SynapseError:
+            raise
+        except CodeMessageException as e:
+            logger.warn("Failed to reject invite: %s", e)
+            raise SynapseError(500, "Failed to reject invite")
 
         context = yield self.state_handler.compute_event_context(event)
 
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py

index f1c3e90ecd..6c7409215a 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -258,10 +258,20 @@ class RoomMemberHandler(BaseHandler):
                 else:
                     # send the rejection to the inviter's HS.
                     remote_room_hosts = remote_room_hosts + [inviter.domain]
-                    ret = yield self.reject_remote_invite(
-                        target.to_string(), room_id, remote_room_hosts
-                    )
-                    defer.returnValue(ret)
+
+                    try:
+                        ret = yield self.reject_remote_invite(
+                            target.to_string(), room_id, remote_room_hosts
+                        )
+                        defer.returnValue(ret)
+                    except SynapseError as e:
+                        logger.warn("Failed to reject invite: %s", e)
+
+                        yield self.store.locally_reject_invite(
+                            target.to_string(), room_id
+                        )
+
+                        defer.returnValue({})
 
         yield self._local_membership_update(
             requester=requester,