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

Synapse 1.21.0rc1 (2020-10-01)
==============================

Features
--------

- Require the user to confirm that their password should be reset after clicking the email confirmation link. ([\#8004](https://github.com/matrix-org/synapse/issues/8004))
- Add an admin API `GET /_synapse/admin/v1/event_reports` to read entries of table `event_reports`. Contributed by @dklimpel. ([\#8217](https://github.com/matrix-org/synapse/issues/8217))
- Consolidate the SSO error template across all configuration. ([\#8248](https://github.com/matrix-org/synapse/issues/8248), [\#8405](https://github.com/matrix-org/synapse/issues/8405))
- Add a configuration option to specify a whitelist of domains that a user can be redirected to after validating their email or phone number. ([\#8275](https://github.com/matrix-org/synapse/issues/8275), [\#8417](https://github.com/matrix-org/synapse/issues/8417))
- Add experimental support for sharding event persister. ([\#8294](https://github.com/matrix-org/synapse/issues/8294), [\#8387](https://github.com/matrix-org/synapse/issues/8387), [\#8396](https://github.com/matrix-org/synapse/issues/8396), [\#8419](https://github.com/matrix-org/synapse/issues/8419))
- Add the room topic and avatar to the room details admin API. ([\#8305](https://github.com/matrix-org/synapse/issues/8305))
- Add an admin API for querying rooms where a user is a member. Contributed by @dklimpel. ([\#8306](https://github.com/matrix-org/synapse/issues/8306))
- Add `uk.half-shot.msc2778.login.application_service` login type to allow appservices to login. ([\#8320](https://github.com/matrix-org/synapse/issues/8320))
- Add a configuration option that allows existing users to log in with OpenID Connect. Contributed by @BBBSnowball and @OmmyZhang. ([\#8345](https://github.com/matrix-org/synapse/issues/8345))
- Add prometheus metrics for replication requests. ([\#8406](https://github.com/matrix-org/synapse/issues/8406))
- Support passing additional single sign-on parameters to the client. ([\#8413](https://github.com/matrix-org/synapse/issues/8413))
- Add experimental reporting of metrics on expensive rooms for state-resolution. ([\#8420](https://github.com/matrix-org/synapse/issues/8420))
- Add experimental prometheus metric to track numbers of "large" rooms for state resolutiom. ([\#8425](https://github.com/matrix-org/synapse/issues/8425))
- Add prometheus metrics to track federation delays. ([\#8430](https://github.com/matrix-org/synapse/issues/8430))

Bugfixes
--------

- Fix a bug in the media repository where remote thumbnails with the same size but different crop methods would overwrite each other. Contributed by @deepbluev7. ([\#7124](https://github.com/matrix-org/synapse/issues/7124))
- Fix inconsistent handling of non-existent push rules, and stop tracking the `enabled` state of removed push rules. ([\#7796](https://github.com/matrix-org/synapse/issues/7796))
- Fix a longstanding bug when storing a media file with an empty `upload_name`. ([\#7905](https://github.com/matrix-org/synapse/issues/7905))
- Fix messages not being sent over federation until an event is sent into the same room. ([\#8230](https://github.com/matrix-org/synapse/issues/8230), [\#8247](https://github.com/matrix-org/synapse/issues/8247), [\#8258](https://github.com/matrix-org/synapse/issues/8258), [\#8272](https://github.com/matrix-org/synapse/issues/8272), [\#8322](https://github.com/matrix-org/synapse/issues/8322))
- Fix a longstanding bug where files that could not be thumbnailed would result in an Internal Server Error. ([\#8236](https://github.com/matrix-org/synapse/issues/8236), [\#8435](https://github.com/matrix-org/synapse/issues/8435))
- Upgrade minimum version of `canonicaljson` to version 1.4.0, to fix an unicode encoding issue. ([\#8262](https://github.com/matrix-org/synapse/issues/8262))
- Fix longstanding bug which could lead to incomplete database upgrades on SQLite. ([\#8265](https://github.com/matrix-org/synapse/issues/8265))
- Fix stack overflow when stderr is redirected to the logging system, and the logging system encounters an error. ([\#8268](https://github.com/matrix-org/synapse/issues/8268))
- Fix a bug which cause the logging system to report errors, if `DEBUG` was enabled and no `context` filter was applied. ([\#8278](https://github.com/matrix-org/synapse/issues/8278))
- Fix edge case where push could get delayed for a user until a later event was pushed. ([\#8287](https://github.com/matrix-org/synapse/issues/8287))
- Fix fetching malformed events from remote servers. ([\#8324](https://github.com/matrix-org/synapse/issues/8324))
- Fix `UnboundLocalError` from occuring when appservices send a malformed register request. ([\#8329](https://github.com/matrix-org/synapse/issues/8329))
- Don't send push notifications to expired user accounts. ([\#8353](https://github.com/matrix-org/synapse/issues/8353))
- Fix a regression in v1.19.0 with reactivating users through the admin API. ([\#8362](https://github.com/matrix-org/synapse/issues/8362))
- Fix a bug where during device registration the length of the device name wasn't limited. ([\#8364](https://github.com/matrix-org/synapse/issues/8364))
- Include `guest_access` in the fields that are checked for null bytes when updating `room_stats_state`. Broke in v1.7.2. ([\#8373](https://github.com/matrix-org/synapse/issues/8373))
- Fix theoretical race condition where events are not sent down `/sync` if the synchrotron worker is restarted without restarting other workers. ([\#8374](https://github.com/matrix-org/synapse/issues/8374))
- Fix a bug which could cause errors in rooms with malformed membership events, on servers using sqlite. ([\#8385](https://github.com/matrix-org/synapse/issues/8385))
- Fix "Re-starting finished log context" warning when receiving an event we already had over federation. ([\#8398](https://github.com/matrix-org/synapse/issues/8398))
- Fix incorrect handling of timeouts on outgoing HTTP requests. ([\#8400](https://github.com/matrix-org/synapse/issues/8400))
- Fix a regression in v1.20.0 in the `synapse_port_db` script regarding the `ui_auth_sessions_ips` table. ([\#8410](https://github.com/matrix-org/synapse/issues/8410))
- Remove unnecessary 3PID registration check when resetting password via an email address. Bug introduced in v0.34.0rc2. ([\#8414](https://github.com/matrix-org/synapse/issues/8414))

Improved Documentation
----------------------

- Add `/_synapse/client` to the reverse proxy documentation. ([\#8227](https://github.com/matrix-org/synapse/issues/8227))
- Add note to the reverse proxy settings documentation about disabling Apache's mod_security2. Contributed by Julian Fietkau (@jfietkau). ([\#8375](https://github.com/matrix-org/synapse/issues/8375))
- Improve description of `server_name` config option in `homserver.yaml`. ([\#8415](https://github.com/matrix-org/synapse/issues/8415))

Deprecations and Removals
-------------------------

- Drop support for `prometheus_client` older than 0.4.0. ([\#8426](https://github.com/matrix-org/synapse/issues/8426))

Internal Changes
----------------

- Fix tests on distros which disable TLSv1.0. Contributed by @danc86. ([\#8208](https://github.com/matrix-org/synapse/issues/8208))
- Simplify the distributor code to avoid unnecessary work. ([\#8216](https://github.com/matrix-org/synapse/issues/8216))
- Remove the `populate_stats_process_rooms_2` background job and restore functionality to `populate_stats_process_rooms`. ([\#8243](https://github.com/matrix-org/synapse/issues/8243))
- Clean up type hints for `PaginationConfig`. ([\#8250](https://github.com/matrix-org/synapse/issues/8250), [\#8282](https://github.com/matrix-org/synapse/issues/8282))
- Track the latest event for every destination and room for catch-up after federation outage. ([\#8256](https://github.com/matrix-org/synapse/issues/8256))
- Fix non-user visible bug in implementation of `MultiWriterIdGenerator.get_current_token_for_writer`. ([\#8257](https://github.com/matrix-org/synapse/issues/8257))
- Switch to the JSON implementation from the standard library. ([\#8259](https://github.com/matrix-org/synapse/issues/8259))
- Add type hints to `synapse.util.async_helpers`. ([\#8260](https://github.com/matrix-org/synapse/issues/8260))
- Simplify tests that mock asynchronous functions. ([\#8261](https://github.com/matrix-org/synapse/issues/8261))
- Add type hints to `StreamToken` and `RoomStreamToken` classes. ([\#8279](https://github.com/matrix-org/synapse/issues/8279))
- Change `StreamToken.room_key` to be a `RoomStreamToken` instance. ([\#8281](https://github.com/matrix-org/synapse/issues/8281))
- Refactor notifier code to correctly use the max event stream position. ([\#8288](https://github.com/matrix-org/synapse/issues/8288))
- Use slotted classes where possible. ([\#8296](https://github.com/matrix-org/synapse/issues/8296))
- Support testing the local Synapse checkout against the [Complement homeserver test suite](https://github.com/matrix-org/complement/). ([\#8317](https://github.com/matrix-org/synapse/issues/8317))
- Update outdated usages of `metaclass` to python 3 syntax. ([\#8326](https://github.com/matrix-org/synapse/issues/8326))
- Move lint-related dependencies to package-extra field, update CONTRIBUTING.md to utilise this. ([\#8330](https://github.com/matrix-org/synapse/issues/8330), [\#8377](https://github.com/matrix-org/synapse/issues/8377))
- Use the `admin_patterns` helper in additional locations. ([\#8331](https://github.com/matrix-org/synapse/issues/8331))
- Fix test logging to allow braces in log output. ([\#8335](https://github.com/matrix-org/synapse/issues/8335))
- Remove `__future__` imports related to Python 2 compatibility. ([\#8337](https://github.com/matrix-org/synapse/issues/8337))
- Simplify `super()` calls to Python 3 syntax. ([\#8344](https://github.com/matrix-org/synapse/issues/8344))
- Fix bad merge from `release-v1.20.0` branch to `develop`. ([\#8354](https://github.com/matrix-org/synapse/issues/8354))
- Factor out a `_send_dummy_event_for_room` method. ([\#8370](https://github.com/matrix-org/synapse/issues/8370))
- Improve logging of state resolution. ([\#8371](https://github.com/matrix-org/synapse/issues/8371))
- Add type annotations to `SimpleHttpClient`. ([\#8372](https://github.com/matrix-org/synapse/issues/8372))
- Refactor ID generators to use `async with` syntax. ([\#8383](https://github.com/matrix-org/synapse/issues/8383))
- Add `EventStreamPosition` type. ([\#8388](https://github.com/matrix-org/synapse/issues/8388))
- Create a mechanism for marking tests "logcontext clean". ([\#8399](https://github.com/matrix-org/synapse/issues/8399))
- A pair of tiny cleanups in the federation request code. ([\#8401](https://github.com/matrix-org/synapse/issues/8401))
- Add checks on startup that PostgreSQL sequences are consistent with their associated tables. ([\#8402](https://github.com/matrix-org/synapse/issues/8402))
- Do not include appservice users when calculating the total MAU for a server. ([\#8404](https://github.com/matrix-org/synapse/issues/8404))
- Typing fixes for `synapse.handlers.federation`. ([\#8422](https://github.com/matrix-org/synapse/issues/8422))
- Various refactors to simplify stream token handling. ([\#8423](https://github.com/matrix-org/synapse/issues/8423))
- Make stream token serializing/deserializing async. ([\#8427](https://github.com/matrix-org/synapse/issues/8427))

Introduced in #8236

we're not doing a final release yet!

Add a pair of federation metrics to track the delays in sending PDUs to/from 
particular servers.

The idea is that in future tokens will encode a mapping of instance to position. However, we don't want to include the full instance name in the string representation, so instead we'll have a mapping between instance name and an immutable integer ID in the DB that we can use instead. We'll then do the lookup when we serialize/deserialize the token (we could alternatively pass around an `Instance` type that includes both the name and ID, but that turns out to be a lot more invasive).

Add an improved "forward extremities" metric

Hopefully, N(extremities) * N(state_events) is a more realistic approximation
to "how big a problem is this room?".

This was a bit unweildy for what I wanted: in particular, I wanted to assign
each measurement straight into a bucket, rather than storing an intermediate
Counter which didn't do any bucketing at all.

I've replaced it with something that is hopefully a bit easier to use.

(I'm not entirely sure what the difference between a HistogramMetricFamily and
a GaugeHistogramMetricFamily is, but given our counters can go down as well as
up the latter *sounds* more accurate?)

Our hacked-up `_exposition.py` was stripping out some samples it shouldn't
have been. Put them back in, to more closely match the upstream
`exposition.py`.

Drop compatibility hacks for prometheus-client pre 0.4.0. Debian stretch and
Fedora 31 both have newer versions, so hopefully this will be ok.

Report metrics on expensive rooms for state res

* Don't check whether a 3pid is allowed to register during password reset

This endpoint should only deal with emails that have already been approved, and
are attached with user's account. There's no need to re-check them here.

* Changelog

* Fix table scan of events on worker startup.

This happened because we assumed "new" writers had an initial stream
position of 0, so the replication code tried to fetch all events written
by the instance between 0 and the current position.

Instead, set the initial position of new writers to the current
persisted up to position, on the assumption that new writers won't have
written anything before that point.

* Consider old writers coming back as "new".

Otherwise we'd try and fetch entries between the old stale token and the
current position, even though it won't have written any rows.

Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>

Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>

For some reason, an apparently unrelated PR upset mypy about this module. Here are a number of little fixes.

Merge branch 'develop' of github.com:matrix-org/synapse into anoa/info-mainline-no-check-password-reset

This PR adds a script that:

* Builds the local Synapse checkout using our existing `docker/Dockerfile` image.
* Downloads [Complement](https://github.com/matrix-org/complement/)'s source code.
* Builds the [Synapse.Dockerfile](https://github.com/matrix-org/complement/blob/master/dockerfiles/Synapse.Dockerfile) using the above dockerfile as a base.
* Builds and runs Complement against it.

This set up differs slightly from [that of the dendrite repo](https://github.com/matrix-org/dendrite/blob/master/build/scripts/complement.sh) (`complement.sh`, `Complement.Dockerfile`), which instead stores a separate, but slightly modified, dockerfile in Dendrite's repo rather than running the one stored in Complement's repo. That synapse equivalent to that dockerfile (`Synapse.Dockerfile`) in Complement's repo is just based on top of `matrixdotorg/synapse:latest`, which we opt to build here locally.

Thus copying over the files from Complement's repo wouldn't change any functionality, and would result in two instances of the same files. So just using the dockerfile in Complement's repo was decided upon instead.

This is an attempt to fix #8403.

Broken in https://github.com/matrix-org/synapse/pull/8275 and has yet to be put in a release. Fixes https://github.com/matrix-org/synapse/issues/8418.

`next_link` is an optional parameter. However, we were checking whether the `next_link` param was valid, even if it wasn't provided. In that case, `next_link` was `None`, which would clearly not be a valid URL.

This would prevent password reset and other operations if `next_link` was not provided, and the `next_link_domain_whitelist` config option was set.

One hope is that this might provide some insights into #3365.

* Remove `on_timeout_cancel` from `timeout_deferred`

The `on_timeout_cancel` param to `timeout_deferred` wasn't always called on a
timeout (in particular if the canceller raised an exception), so it was
unreliable. It was also only used in one place, and to be honest it's easier to
do what it does a different way.

* Fix handling of connection timeouts in outgoing http requests

Turns out that if we get a timeout during connection, then a different
exception is raised, which wasn't always handled correctly.

To fix it, catch the exception in SimpleHttpClient and turn it into a
RequestTimedOutError (which is already a documented exception).

Also add a description to RequestTimedOutError so that we can see which stage
it failed at.

* Fix incorrect handling of timeouts reading federation responses

This was trapping the wrong sort of TimeoutError, so was never being hit.

The effect was relatively minor, but we should fix this so that it does the
expected thing.

* Fix inconsistent handling of `timeout` param between methods

`get_json`, `put_json` and `delete_json` were applying a different timeout to
the response body to `post_json`; bring them in line and test.

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>
Co-authored-by: Erik Johnston <erik@matrix.org>

This endpoint should only deal with emails that have already been approved, and
are attached with user's account. There's no need to re-check them here.