* Fix presence timeouts when synchrotron restarts.
Handling timeouts would fail if there was an external process that had
timed out, e.g. a synchrotron restarting. This was due to a couple of
variable name typoes.
Fixes#3715.
Hopefully this will fix the occasional failures we were seeing in the room directory.
The problem was that events are not necessarily persisted (and `current_state_delta_stream` updated) in the same order as their stream_id. So for instance current_state_delta 9 might be persisted *before* current_state_delta 8. Then, when the room stats saw stream_id 9, it assumed it had done everything up to 9, and never came back to do stream_id 8.
We can solve this easily by only processing up to the stream_id where we know all events have been persisted.
It turns out that _local_membership_update doesn't run when you join a new, remote room. It only runs if you're joining a room that your server already knows about. This would explain #4703 and #5295 and why the transfer would work in testing and some rooms, but not others. This would especially hit single-user homeservers.
The check has been moved to right after the room has been joined, and works much more reliably. (Though it may still be a bit awkward of a place).
We incorrectly used `room_id` as to bound the result set, even though we
order by `joined_members, room_id`, leading to incorrect results after
pagination.
Copy push rules during a room upgrade from the old room to the new room, instead of deleting them from the old room.
For instance, we've defined upgrading of a room multiple times to be possible, and push rules won't be transferred on the second upgrade if they're deleted during the first.
Also fix some missing yields that probably broke things quite a bit.
While this is not documented in the spec (but should be), Riot (and other clients) revoke 3PID invites by sending a m.room.third_party_invite event with an empty ({}) content to the room's state.
When the invited 3PID gets associated with a MXID, the identity server (which doesn't know about revocations) sends down to the MXID's homeserver all of the undelivered invites it has for this 3PID. The homeserver then tries to talk to the inviting homeserver in order to exchange these invite for m.room.member events.
When one of the invite is revoked, the inviting homeserver responds with a 500 error because it tries to extract a 'display_name' property from the content, which is empty. This might cause the invited server to consider that the server is down and not try to exchange other, valid invites (or at least delay it).
This fix handles the case of revoked invites by avoiding trying to fetch a 'display_name' from the original invite's content, and letting the m.room.member event fail the auth rules (because, since the original invite's content is empty, it doesn't have public keys), which results in sending a 403 with the correct error message to the invited server.
Pull the checkers out to their own classes, rather than having them lost in a
massive 1000-line class which does everything.
This is also preparation for some more intelligent advertising of flows, as per #6100
