This fixes a weird bug where, if you were determined enough, you could end up with a rejected event forming part of the state at a backwards-extremity. Authing that backwards extrem would then lead to us trying to pull the rejected event from the db (with allow_rejected=False), which would fail with a 404.
When we request the state/auth_events to populate a backwards extremity (on
backfill or in the case of missing events in a transaction push), we should
check that the returned events are in the right room rather than blindly using
them in the room state or auth chain.
Given that _get_events_from_store_or_dest takes a room_id, it seems clear that
it should be sanity-checking the room_id of the requested events, so let's do
it there.
Make it return the state *after* the requested event, rather than the one
before it. This is a bit easier and requires fewer calls to
get_events_from_store_or_dest.
This fixes a weird bug where, if you were determined enough, you could end up with a rejected event forming part of the state at a backwards-extremity. Authing that backwards extrem would then lead to us trying to pull the rejected event from the db (with allow_rejected=False), which would fail with a 404.
When we request the state/auth_events to populate a backwards extremity (on
backfill or in the case of missing events in a transaction push), we should
check that the returned events are in the right room rather than blindly using
them in the room state or auth chain.
Given that _get_events_from_store_or_dest takes a room_id, it seems clear that
it should be sanity-checking the room_id of the requested events, so let's do
it there.
Make it return the state *after* the requested event, rather than the one
before it. This is a bit easier and requires fewer calls to
get_events_from_store_or_dest.
PaginationHandler.get_messages is only called by RoomMessageListRestServlet,
which is async.
Chase the code path down from there:
- FederationHandler.maybe_backfill (and nested try_backfill)
- FederationHandler.backfill
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
Fixes a bug where rejected events were persisted with the wrong state group.
Also fixes an occasional internal-server-error when receiving events over
federation which are rejected and (possibly because they are
backwards-extremities) have no prev_group.
Fixes#6289.
* Raise an exception if accessing state for rejected events
Add some sanity checks on accessing state_group etc for
rejected events.
* Skip calculating push actions for rejected events
It didn't actually cause any bugs, because rejected events get filtered out at
various later points, but there's not point in trying to calculate the push
actions for a rejected event.
The intention here is to make it clearer which fields we can expect to be
populated when: notably, that the _event_type etc aren't used for the
synchronous impl of EventContext.
Erik Johnston