Introduce `Clock.call_when_running(...)` to wrap startup code in a
logcontext, ensuring we can identify which server generated the logs.
Background:
> Ideally, nothing from the Synapse homeserver would be logged against the `sentinel`
> logcontext as we want to know which server the logs came from. In practice, this is not
> always the case yet especially outside of request handling.
>
> Global things outside of Synapse (e.g. Twisted reactor code) should run in the
> `sentinel` logcontext. It's only when it calls into application code that a logcontext
> gets activated. This means the reactor should be started in the `sentinel` logcontext,
> and any time an awaitable yields control back to the reactor, it should reset the
> logcontext to be the `sentinel` logcontext. This is important to avoid leaking the
> current logcontext to the reactor (which would then get picked up and associated with
> the next thing the reactor does).
>
> *-- `docs/log_contexts.md`
Also adds a lint to prefer `Clock.call_when_running(...)` over
`reactor.callWhenRunning(...)`
Part of https://github.com/element-hq/synapse/issues/18905
This is basically exactly the same logic as for receipts. Essentially we
just need to track which room account data we have and haven't sent down
to clients, and use that when we pull stuff out.
I think this just needs a couple of extra tests written
---------
Co-authored-by: Eric Eastwood <eric.eastwood@beta.gouv.fr>
I thought ruff check would also format, but it doesn't.
This runs ruff format in CI and dev scripts. The first commit is just a
run of `ruff format .` in the root directory.
