Synapse 1.19.3 (2020-09-18)
===========================
Bugfixes
--------
- Partially mitigate bug where newly joined servers couldn't get past
events in a room when there is a malformed event.
([\#8350](https://github.com/matrix-org/synapse/issues/8350))
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Merge tag 'v1.19.3' into release-v1.20.0
1.19.3
Synapse 1.19.3 (2020-09-18)
===========================
Bugfixes
--------
- Partially mitigate bug where newly joined servers couldn't get past
events in a room when there is a malformed event.
([\#8350](https://github.com/matrix-org/synapse/issues/8350))
This is a bit of a hack, as `_check_sigs_and_hash_and_fetch` is intended
for attempting to pull an event from the database/(re)pull it from the
server that originally sent the event if checking the signature of the
event fails.
During backfill we *know* that we won't have the event in our database,
however it is still useful to be able to query the original sending
server as the server we're backfilling from may be acting maliciously.
The main benefit and reason for this change however is that
`_check_sigs_and_hash_and_fetch` will drop an event during backfill if
it cannot be successfully validated, whereas the current code will
simply fail the backfill request - resulting in the client's /messages
request silently being dropped.
This is a quick patch to fix backfilling rooms that contain malformed
events. A better implementation in planned in future.
Instead of just using the most recent extremities let's pick the
ones that will give us results that the pagination request cares about,
i.e. pick extremities only if they have a smaller depth than the
pagination token.
This is useful when we fail to backfill an extremity, as we no longer
get stuck requesting that same extremity repeatedly.
* Fixup `ALTER TABLE` database queries
Make the new columns nullable, because doing otherwise can wedge a
server with a big database, as setting a default value rewrites the
table.
* Switch back to using the notifications count in the push badge
Clients are likely to be confused if we send a push but the badge count
is the unread messages one, and not the notifications one.
* Changelog
This is *not* ready for production yet. Caveats:
1. We should write some tests...
2. The stream token that we use for events can get stalled at the minimum position of all writers. This means that new events may not be processed and e.g. sent down sync streams if a writer isn't writing or is slow.
