This splits apart `handle_new_user` into a function which adds an entry to the `user_directory` and a function which updates the room sharing tables. I plan to continue doing more of this kind of refactoring to clarify the implementation.

The shared ratelimit function was replaced with a dedicated
RequestRatelimiter class (accessible from the HomeServer
object).

Other properties were copied to each sub-class that inherited
from BaseHandler.

Use `PreserveLoggingContext()` to ensure that logging contexts are not
lost when exiting a read/write lock.

When exiting a read/write lock, callbacks on a `Deferred` are triggered
as a signal to any waiting coroutines. Any waiting coroutine that
becomes runnable is likely to follow the Synapse logging context rules
and will restore its own logging context, then either run to completion
or await another `Deferred`, resetting the logging context in the
process.

This also turns off calculating code coverage, as we didn't use it and it was a lot of noise

Hopefully this fixes these tests sometimes failing in CI.

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>

Include the event ids being peristed

Looks like the wrong exception type was caught in #10932.

* `disallow-untyped-defs` for `synapse.state`

Much smaller than I was expecting!

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

This is in the context of creating new module callbacks that modules in https://github.com/matrix-org/synapse-dinsic can use, in an effort to reconcile the spam checker API in synapse-dinsic with the one in mainline.

Note that a module callback already exists for 3pid invites (https://matrix-org.github.io/synapse/develop/modules/third_party_rules_callbacks.html#check_threepid_can_be_invited) but it doesn't check whether the sender of the invite is allowed to send it.

This removes the magic allowing accessing configurable
variables directly from the config object. It is now required
that a specific configuration class is used (e.g. `config.foo`
must be replaced with `config.server.foo`).

Co-authored-by: Erik Johnston <erik@matrix.org>

Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>

Fix a long-standing bug where a batch of user directory changes would be
silently dropped if the server left a room early in the batch.

* Pull out `wait_for_background_update` in tests

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>
Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

Signed-off-by: Nick Barrett <nick@beeper.com>

The following modules now pass `disallow_untyped_defs`:

* synapse.util.caches.cached_call 
* synapse.util.caches.lrucache
* synapse.util.caches.response_cache 
* synapse.util.caches.stream_change_cache
* synapse.util.caches.ttlcache pass
* synapse.util.daemonize
* synapse.util.patch_inline_callbacks pass `no-untyped-defs`
* synapse.util.versionstring

Additional typing in synapse.util.metrics. Didn't get this to pass `no-untyped-defs`, think I'll need to watch #10847

There are two steps to rebuilding the user directory:

1. a scan over rooms, followed by
2. a scan over local users.

The former reads avatars and display names from the `room_memberships`
table and therefore contains potentially private avatars and
display names. The latter reads from the the `profiles` table which only
contains public data; moreover it will overwrite any private profiles
that the rooms scan may have written to the user directory. This means
that the rebuild could leak private user while the rebuild was in
progress, only to later cover up the leaks once the rebuild had completed.

This change skips over local users when writing user_directory rows
when scanning rooms. Doing so means that it'll take longer for a rebuild
to make local users searchable, which is unfortunate. I think a future
PR can improve this by swapping the order of the two steps above. (And
indeed there's more to do here, e.g. copying from `profiles` without
going via Python.)

Small tidy-ups while I'm here:

* Remove duplicated code from test_initial. This was meant to be pulled into `purge_and_rebuild_user_dir`.
* Move `is_public` before updating sharing tables. No functional change; it's still before the first read of `is_public`.
* Don't bother creating a set from dict keys. Slightly nicer and makes the code simpler.

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

We correctly allowed using the MSC2716 batch endpoint for
the room creator in existing room versions but accidentally didn't track
the events because of a logic flaw.

This prevented you from connecting subsequent chunks together because it would
throw the unknown batch ID error.

We only want to process MSC2716 events when:

 - The room version supports MSC2716
 - Any room where the homeserver has the `msc2716_enabled` experimental feature enabled and the event is from the room creator

When we consider whether to accept events, we should not accept those which
depend on rejected events for their auth events.

This (together with earlier changes such as
https://github.com/matrix-org/synapse/pull/10771 and
https://github.com/matrix-org/synapse/pull/10896) forms a partial fix to
https://github.com/matrix-org/synapse/issues/9595. There still remain code
paths where we do not check the `auth_events` at all.

`_check_event_auth` is only called in two places, and only one of those sets
`send_on_behalf_of`. Warming the cache isn't really part of auth anyway, so
moving it out makes a lot more sense.

Add some more comments about wtf is going on here.

There's little point in doing a fancy state reconciliation dance if the event
itself is invalid.

Likewise, there's no point checking it again in `_check_for_soft_fail`.

Based on matrix-doc switching from master -> main and
MSCs being merged.

Make it easier to track down where opentracing spans are going missing
by including stack traces in the logs.

* add test

* add function to remove user from monthly active table in deactivate code

* add function to remove user from monthly active table

* add changelog entry

* update changelog number

* requested changes

* update docstring on new function

* fix lint error

* Update synapse/storage/databases/main/monthly_active_users.py

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

Signed-off-by: Andrew Ferrazzutti <fair@miscworks.net>

Synapse 1.44.0rc3 (2021-10-04)
==============================

Bugfixes
--------

- Fix a bug introduced in Synapse v1.40.0 where changing a user's display name or avatar in a restricted room would cause an authentication error. ([\#10933](https://github.com/matrix-org/synapse/issues/10933))
- Fix `/admin/whois/{user_id}` endpoint, which was broken in v1.44.0rc1. ([\#10968](https://github.com/matrix-org/synapse/issues/10968))

* Introduce `should_include_local_users_in_dir`

We exclude three kinds of local users from the user_directory tables. At
present we don't consistently exclude all three in the same places. This
commit introduces a new function to gather those exclusion conditions
together. Because we have to handle local and remote users in different
ways, I've made that function only consider the case of remote users.
It's the caller's responsibility to make the local versus remote
distinction clear and correct.

A test fixup is required. The test now hits a path which makes db
queries against the users table. The expected rows were missing, because
we were using a dummy user that hadn't actually been registered.

We also add new test cases to covert the exclusion logic.

----

By my reading this makes these changes:

* When an app service user registers or changes their profile, they will
  _not_ be added to the user directory. (Previously only support and
  deactivated users were excluded). This is consistent with the logic that
  rebuilds the user directory. See also [the discussion
  here](https://github.com/matrix-org/synapse/pull/10914#discussion_r716859548

).
* When rebuilding the directory, exclude support and disabled users from
  room sharing tables. Previously only appservice users were excluded.
* Exclude all three categories of local users when rebuilding the
  directory. Previously `_populate_user_directory_process_users` didn't do
  any exclusion.

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>