Make `POST /_matrix/client/v3/rooms/{roomId}/report/{eventId}` endpoint return 404 if event exists, but the user lacks access (#15300)

Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>

When a room is deleted in Synapse we remove the event forward
extremities in the room, so if (say a bot) tries to send a message into
the room we error out due to not being able to calculate prev events for
the new event *before* we check if the sender is in the room.

Fixes #8094

Separates REST layer code from the actual URL previewing.

Make `configure_workers_and_start` script used in Complement tests compatible with older versions of Python. (#15275)

With Redis commands do not need to be re-issued by the main
process (they fan-out to all processes at once) and thus it is no
longer necessary to worry about them reflecting recursively forever.

Signed-off-by: Tulir Asokan <tulir@maunium.net>

Refresh remote profiles that have been marked as stale, in order to fill the user directory. [rei:userdirpriv] (#14756)

* Scaffolding for background process to refresh profiles

* Add scaffolding for background process to refresh profiles for a given server

* Implement the code to select servers to refresh from

* Ensure we don't build up multiple looping calls

* Make `get_profile` able to respect backoffs

* Add logic for refreshing users

* When backing off, schedule a refresh when the backoff is over

* Wake up the background processes when we receive an interesting state event

* Add tests

* Newsfile

Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>

* Add comment about 1<<62

---------

Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>

Preparatory work to fix the user directory assuming that any remote membership state events represent a profile change. [rei:userdirpriv] (#14755)

* Remove special-case method for new memberships only, use more generic method

* Only collect profiles from state events in public rooms

* Add a table to track stale remote user profiles

* Add store methods to set and delete rows in this new table

* Mark remote profiles as stale when a member state event comes in to a private room

* Newsfile

Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>

* Simplify by removing Optionality of `event_id`

* Replace names and avatars with None if they're set to dodgy things

I think this makes more sense anyway.

* Move schema delta to 74 (I missed the boat?)

* Turns out these can be None after all

---------

Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>

Co-authored-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>

It is not necessary to reach out to the database to check some
parameters if the auto-join rooms are not configured, or (in some cases)
if auto-create rooms is not configured.

* Bump cryptography from 39.0.1 to 39.0.2

Bumps [cryptography](https://github.com/pyca/cryptography) from 39.0.1 to 39.0.2.
- [Release notes](https://github.com/pyca/cryptography/releases)
- [Changelog](https://github.com/pyca/cryptography/blob/main/CHANGELOG.rst)
- [Commits](https://github.com/pyca/cryptography/compare/39.0.1...39.0.2

)

---
updated-dependencies:
- dependency-name: cryptography
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

* Changelog

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: GitHub Actions <github-actions[bot]@users.noreply.github.com>