Checks that the localpart returned by mapping providers for SAML and
OIDC are valid before registering new users.

Extends the OIDC tests for existing users and invalid data.

* Consistently use room_id from federation request body

Some federation APIs have a redundant `room_id` path param (see
https://github.com/matrix-org/matrix-doc/issues/2330). We should make sure we
consistently use either the path param or the body param, and the body param is
easier.

* Kill off some references to "context"

Once upon a time, "rooms" were known as "contexts". I think this kills of the
last references to "contexts".

De-duplicates code between the SAML and OIDC implementations.

Fixes #4042

We do it this way round so that only the "owner" can delete the access token (i.e. `/logout/all` by the "owner" also deletes that token, but `/logout/all` by the "target user" doesn't).

A future PR will add an API for creating such a token.

When the target user and authenticated entity are different the `Processed request` log line will be logged with a: `{@admin:server as @bob:server} ...`. I'm not convinced by that format (especially since it adds spaces in there, making it harder to use `cut -d ' '` to chop off the start of log lines). Suggestions welcome.

#8567 started a span for every background process. This is good as it means all Synapse code that gets run should be in a span (unless in the sentinel logging context), but it means we generate about 15x the number of spans as we did previously.

This PR attempts to reduce that number by a) not starting one for send commands to Redis, and b) deferring starting background processes until after we're sure they're necessary.

I don't really know how much this will help.

* Fix outbound federaion with multiple event persisters.

We incorrectly notified federation senders that the minimum persisted
stream position had advanced when we got an `RDATA` from an event
persister.

Notifying of federation senders already correctly happens in the
notifier, so we just delete the offending line.

* Change some interfaces to use RoomStreamToken.

By enforcing use of `RoomStreamTokens` we make it less likely that
people pass in random ints that they got from somewhere random.

Update `EventCreationHandler.create_event` to accept an auth_events param, and
use it in `_locally_reject_invite` instead of reinventing the wheel.

this is always the same as requester.access_token_id.

Should fix #3365.

All handlers now available via get_*_handler() methods on the HomeServer.

This allows a user to store an offline device on the server and
then restore it at a subsequent login.

This is now redundant, and we can just call `handle_new_client_event` directly.

This allows for connecting to certain IdPs, e.g. GitLab.

Co-authored-by: Benjamin Koch <bbbsnowball@gmail.com>

This adds configuration flags that will match a user to pre-existing users
when logging in via OpenID Connect. This is useful when switching to
an existing SSO system.

* Create a new function to verify that the length of a device name is
under a certain threshold.
* Refactor old code and tests to use said function.
* Verify device name length during registration of device
* Add a test for the above

Signed-off-by: Dionysis Grigoropoulos <dgrig@erethon.com>

This converts calls like super(Foo, self) -> super().

Generated with:

    sed -i "" -Ee 's/super\([^\(]+\)/super()/g' **/*.py

`pusher_pool.on_new_notifications` expected a min and max stream ID, however that was not what we were passing in. Instead, let's just pass it the current max stream ID and have it track the last stream ID it got passed.

I believe that it mostly worked as we called the function for every event. However, it would break for events that got persisted out of order, i.e, that were persisted but the max stream ID wasn't incremented as not all preceding events had finished persisting, and push for that event would be delayed until another event got pushed to the effected users.

This reverts commit e7fd336a.

Rename 'populate_stats_process_rooms_2' background job back to 'populate_stats_process_rooms' again (#8243)

Fixes https://github.com/matrix-org/synapse/issues/8238

Alongside the delta file, some changes were also necessary to the codebase to remove references to the now defunct `populate_stats_process_rooms_2` background job. Thankfully the latter doesn't seem to have made it into any documentation yet :)