Calling the invalidation function during initialisation of the data
stores introduces a circular dependency, causing Synapse to fail to
start.

Fix typo in _select_thumbnail

These now exist in the pipelines repo.

The old statement returned `None` for such a `password_config` (like the one
created on first run), thus retrieval of the `pepper` key failed with
`AttributeError`.

Fixes #5315

Signed-off-by: Ivan Vilata i Balaguer <ivan@selidor.net>

* Raise an exception if there are pending background updates

So we return with a non-0 code

* Changelog

* Port synapse_port_db to async/await

* Port update_database to async/await

* Add version string to mocked homeservers

* Remove unused imports

* Convert overseen bits to async/await

* Fixup logging contexts

* Fix imports

* Add a way to print an error without raising an exception

* Incorporate review

Co-Authored-By: Erik Johnston <erik@matrix.org>

This reverts commit 11c23af4.

So we can debug issues like #6683 more easily

Fix #6727
Related #6655

Co-authored-by: Erik Johnston <erikj@jki.re>

Fix instantiation of message retention purge jobs