have_events was a map from event_id to rejection reason (or None) for events
which are in our local database. It was used as filter on the list of
event_ids being passed into get_events_as_list. However, since
get_events_as_list will ignore any event_ids that are unknown or rejected, we
can equivalently just leave it to get_events_as_list to do the filtering.
That means that we don't have to keep `have_events` up-to-date, and can use
`have_seen_events` instead of `get_seen_events_with_rejection` in the one place
we do need it.
Implement part [MSC2228](https://github.com/matrix-org/matrix-doc/pull/2228). The parts that differ are:
* the feature is hidden behind a configuration flag (`enable_ephemeral_messages`)
* self-destruction doesn't happen for state events
* only implement support for the `m.self_destruct_after` field (not the `m.self_destruct` one)
* doesn't send synthetic redactions to clients because for this specific case we consider the clients to be able to destroy an event themselves, instead we just censor it (by pruning its JSON) in the database
=============================
Bugfixes
--------
- Fix a bug which could cause the background database update hander for event labels to get stuck in a loop raising exceptions. ([\#6407](https://github.com/matrix-org/synapse/issues/6407))
-----BEGIN PGP SIGNATURE-----
iQEzBAABCAAdFiEEv27Axt/F4vrTL/8QOSor00I9eP8FAl3b1yUACgkQOSor00I9
eP/dWQf+ORS/B853qyH5KPZ66o6d7WudSewPmEkFD3747CBevxBsTPETijkqTBlo
WPOmQy9i5OUWpsFYrsrCH+ATpr0JYaIuuoHsIFq/BPFFUx64qrgDwL+X4QEShwAm
kjGNtCMP6VNGjM6MqFepRHSTbIEamCCS665CgVJtqgRYRaAJYI3SQDQ64+ALcbx3
clFZowKV2EtfqhYR7HuBUuxuRjRPGcciNVyjMQFkKq91gKsO4rjPttvE4Bok29ia
/uqFB6T0qty/81T708teZGgB/3/bYK4RtUA4lZCHBNeUejj26bESTI691RfBAEde
to+D7xjA5zaMP3atYNlrvRrqK7Mm3w==
=ucJN
-----END PGP SIGNATURE-----
Merge tag 'v1.6.0rc2' into develop
Synapse 1.6.0rc2 (2019-11-25)
=============================
Bugfixes
--------
- Fix a bug which could cause the background database update hander for event labels to get stuck in a loop raising exceptions. ([\#6407](https://github.com/matrix-org/synapse/issues/6407))
Erik Johnston