* Wrap `auth.get_user_by_req` in an opentracing span

give `get_user_by_req` its own opentracing span, since it can result in a
non-trivial number of sub-spans which it is useful to group together.

This requires a bit of reorganisation because it also sets some tags (and may
force tracing) on the servlet span.

* Emit opentracing span for encoding json responses

This can be a significant time sink.

* Rename all sync spans with a prefix

* Write an opentracing span for encoding sync response

* opentracing span to group generate_room_entries

* opentracing spans within sync.encode_response

* changelog

* Use the `trace` decorator instead of context managers

And make bundling aggregations opt-in, instead of opt-out to avoid
having APIs to include extraneous data (and being much heavier than
necessary).

This adds some opentracing annotations to ResponseCache, to make it easier to see what's going on; in particular, it adds a link back to the initial trace which is actually doing the work of generating the response.

* remove `start_active_span_from_request`

Instead, pull out a separate function, `span_context_from_request`, to extract
the parent span, which we can then pass into `start_active_span` as
normal. This seems to be clearer all round.

* Remove redundant tags from `incoming-federation-request`

These are all wrapped up inside a parent span generated in AsyncResource, so
there's no point duplicating all the tags that are set there.

* Leave request spans open until the request completes

It may take some time for the response to be encoded into JSON, and that JSON
to be streamed back to the client, and really we want that inside the top-level
span, so let's hand responsibility for closure to the SynapseRequest.

* opentracing logs for HTTP request events

* changelog

* Disable aggregation bundling on `/sync` responses

A partial revert of #11478. This turns out to have had a significant CPU impact
on initial-sync handling. For now, let's disable it, until we find a more
efficient way of achieving this.

* Fix tests.

Co-authored-by: Patrick Cloke <patrickc@matrix.org>

Instead of returning 404 errors with HTML bodies when an unknown
prefix was requested (e.g. /matrix/client/v1 before Synapse v1.49.0).

Instead of the backported version.

As suggested in https://github.com/matrix-org/matrix-react-sdk/pull/7372#discussion_r769523369

Instead of Iterable since the generators are not allowed due
to the potential for their re-use.

Add experimental support for MSC3202: allowing application services to masquerade as specific devices. (#11538)

Synapse 1.49.0 (2021-12-14)
===========================

No significant changes since version 1.49.0rc1.

Support for Ubuntu 21.04 ends next month on the 20th of January
---------------------------------------------------------------

For users of Ubuntu 21.04 (Hirsute Hippo), please be aware that [upstream support for this version of Ubuntu will end next month][Ubuntu2104EOL].
We will stop producing packages for Ubuntu 21.04 after upstream support ends.

[Ubuntu2104EOL]: https://lists.ubuntu.com/archives/ubuntu-announce/2021-December/000275.html

The wiki has been migrated to the documentation website
-------------------------------------------------------

We've decided to move the existing, somewhat stagnant pages from the GitHub wiki
to the [documentation website](https://matrix-org.github.io/synapse/latest/).

This was done for two reasons. The first was to ensure that changes are checked by
multiple authors before being committed (everyone makes mistakes!) and the second
was visibility of the documentation. Not everyone knows that Synapse has some very
useful information hidden away in its GitHub wiki pages. Bringing them to the
documentation website should help with visibility, as well as keep all Synapse documentation
in one, easily-searchable location.

Note that contributions to the documentation website happen through [GitHub pull
requests](https://github.com/matrix-org/synapse/pulls). Please visit [#synapse-dev:matrix.org](https://matrix.to/#/#synapse-dev:matrix.org)
if you need help with the process!

Synapse 1.49.0rc1 (2021-12-07)
==============================

Features
--------

- Add [MSC3030](https://github.com/matrix-org/matrix-doc/pull/3030) experimental client and federation API endpoints to get the closest event to a given timestamp. ([\#9445](https://github.com/matrix-org/synapse/issues/9445))
- Include bundled relation aggregations during a limited `/sync` request and `/relations` request, per [MSC2675](https://github.com/matrix-org/matrix-doc/pull/2675). ([\#11284](https://github.com/matrix-org/synapse/issues/11284), [\#11478](https://github.com/matrix-org/synapse/issues/11478))
- Add plugin support for controlling database background updates. ([\#11306](https://github.com/matrix-org/synapse/issues/11306), [\#11475](https://github.com/matrix-org/synapse/issues/11475), [\#11479](https://github.com/matrix-org/synapse/issues/11479))
- Support the stable API endpoints for [MSC2946](https://github.com/matrix-org/matrix-doc/pull/2946): the room `/hierarchy` endpoint. ([\#11329](https://github.com/matrix-org/synapse/issues/11329))
- Add admin API to get some information about federation status with remote servers. ([\#11407](https://github.com/matrix-org/synapse/issues/11407))
- Support expiry of refresh tokens and expiry of the overall session when refresh tokens are in use. ([\#11425](https://github.com/matrix-org/synapse/issues/11425))
- Stabilise support for [MSC2918](https://github.com/matrix-org/matrix-doc/blob/main/proposals/2918-refreshtokens.md#msc2918-refresh-tokens) refresh tokens as they have now been merged into the Matrix specification. ([\#11435](https://github.com/matrix-org/synapse/issues/11435), [\#11522](https://github.com/matrix-org/synapse/issues/11522))
- Update [MSC2918 refresh token](https://github.com/matrix-org/matrix-doc/blob/main/proposals/2918-refreshtokens.md#msc2918-refresh-tokens) support to confirm with the latest revision: accept the `refresh_tokens` parameter in the request body rather than in the URL parameters. ([\#11430](https://github.com/matrix-org/synapse/issues/11430))
- Support configuring the lifetime of non-refreshable access tokens separately to refreshable access tokens. ([\#11445](https://github.com/matrix-org/synapse/issues/11445))
- Expose `synapse_homeserver` and `synapse_worker` commands as entry points to run Synapse's main process and worker processes, respectively. Contributed by @Ma27. ([\#11449](https://github.com/matrix-org/synapse/issues/11449))
- `synctl stop` will now wait for Synapse to exit before returning. ([\#11459](https://github.com/matrix-org/synapse/issues/11459), [\#11490](https://github.com/matrix-org/synapse/issues/11490))
- Extend the "delete room" admin api to work correctly on rooms which have previously been partially deleted. ([\#11523](https://github.com/matrix-org/synapse/issues/11523))
- Add support for the `/_matrix/client/v3/login/sso/redirect/{idpId}` API from Matrix v1.1. This endpoint was overlooked when support for v3 endpoints was added in Synapse 1.48.0rc1. ([\#11451](https://github.com/matrix-org/synapse/issues/11451))

Bugfixes
--------

- Fix using [MSC2716](https://github.com/matrix-org/matrix-doc/pull/2716) batch sending in combination with event persistence workers. Contributed by @tulir at Beeper. ([\#11220](https://github.com/matrix-org/synapse/issues/11220))
- Fix a long-standing bug where all requests that read events from the database could get stuck as a result of losing the database connection, properly this time. Also fix a race condition introduced in the previous insufficient fix in Synapse 1.47.0. ([\#11376](https://github.com/matrix-org/synapse/issues/11376))
- The `/send_join` response now includes the stable `event` field instead of the unstable field from [MSC3083](https://github.com/matrix-org/matrix-doc/pull/3083). ([\#11413](https://github.com/matrix-org/synapse/issues/11413))
- Fix a bug introduced in Synapse 1.47.0 where `send_join` could fail due to an outdated `ijson` version. ([\#11439](https://github.com/matrix-org/synapse/issues/11439), [\#11441](https://github.com/matrix-org/synapse/issues/11441), [\#11460](https://github.com/matrix-org/synapse/issues/11460))
- Fix a bug introduced in Synapse 1.36.0 which could cause problems fetching event-signing keys from trusted key servers. ([\#11440](https://github.com/matrix-org/synapse/issues/11440))
- Fix a bug introduced in Synapse 1.47.1 where the media repository would fail to work if the media store path contained any symbolic links. ([\#11446](https://github.com/matrix-org/synapse/issues/11446))
- Fix an `LruCache` corruption bug, introduced in Synapse 1.38.0, that would cause certain requests to fail until the next Synapse restart. ([\#11454](https://github.com/matrix-org/synapse/issues/11454))
- Fix a long-standing bug where invites from ignored users were included in incremental syncs. ([\#11511](https://github.com/matrix-org/synapse/issues/11511))
- Fix a regression in Synapse 1.48.0 where presence workers would not clear their presence updates over replication on shutdown. ([\#11518](https://github.com/matrix-org/synapse/issues/11518))
- Fix a regression in Synapse 1.48.0 where the module API's `looping_background_call` method would spam errors to the logs when given a non-async function. ([\#11524](https://github.com/matrix-org/synapse/issues/11524))

Updates to the Docker image
---------------------------

- Update `Dockerfile-workers` to healthcheck all workers in the container. ([\#11429](https://github.com/matrix-org/synapse/issues/11429))

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

- Update the media repository documentation. ([\#11415](https://github.com/matrix-org/synapse/issues/11415))
- Update section about backward extremities in the room DAG concepts doc to correct the misconception about backward extremities indicating whether we have fetched an events' `prev_events`. ([\#11469](https://github.com/matrix-org/synapse/issues/11469))

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

- Add `Final` annotation to string constants in `synapse.api.constants` so that they get typed as `Literal`s. ([\#11356](https://github.com/matrix-org/synapse/issues/11356))
- Add a check to ensure that users cannot start the Synapse master process when `worker_app` is set. ([\#11416](https://github.com/matrix-org/synapse/issues/11416))
- Add a note about postgres memory management and hugepages to postgres doc. ([\#11467](https://github.com/matrix-org/synapse/issues/11467))
- Add missing type hints to `synapse.config` module. ([\#11465](https://github.com/matrix-org/synapse/issues/11465))
- Add missing type hints to `synapse.federation`. ([\#11483](https://github.com/matrix-org/synapse/issues/11483))
- Add type annotations to `tests.storage.test_appservice`. ([\#11488](https://github.com/matrix-org/synapse/issues/11488), [\#11492](https://github.com/matrix-org/synapse/issues/11492))
- Add type annotations to some of the configuration surrounding refresh tokens. ([\#11428](https://github.com/matrix-org/synapse/issues/11428))
- Add type hints to `synapse/tests/rest/admin`. ([\#11501](https://github.com/matrix-org/synapse/issues/11501))
- Add type hints to storage classes. ([\#11411](https://github.com/matrix-org/synapse/issues/11411))
- Add wiki pages to documentation website. ([\#11402](https://github.com/matrix-org/synapse/issues/11402))
- Clean up `tests.storage.test_main` to remove use of legacy code. ([\#11493](https://github.com/matrix-org/synapse/issues/11493))
- Clean up `tests.test_visibility` to remove legacy code. ([\#11495](https://github.com/matrix-org/synapse/issues/11495))
- Convert status codes to `HTTPStatus` in `synapse.rest.admin`. ([\#11452](https://github.com/matrix-org/synapse/issues/11452), [\#11455](https://github.com/matrix-org/synapse/issues/11455))
- Extend the `scripts-dev/sign_json` script to support signing events. ([\#11486](https://github.com/matrix-org/synapse/issues/11486))
- Improve internal types in push code. ([\#11409](https://github.com/matrix-org/synapse/issues/11409))
- Improve type annotations in `synapse.module_api`. ([\#11029](https://github.com/matrix-org/synapse/issues/11029))
- Improve type hints for `LruCache`. ([\#11453](https://github.com/matrix-org/synapse/issues/11453))
- Preparation for database schema simplifications: disambiguate queries on `state_key`. ([\#11497](https://github.com/matrix-org/synapse/issues/11497))
- Refactor `backfilled` into specific behavior function arguments (`_persist_events_and_state_updates` and downstream calls). ([\#11417](https://github.com/matrix-org/synapse/issues/11417))
- Refactor `get_version_string` to fix-up types and duplicated code. ([\#11468](https://github.com/matrix-org/synapse/issues/11468))
- Refactor various parts of the `/sync` handler. ([\#11494](https://github.com/matrix-org/synapse/issues/11494), [\#11515](https://github.com/matrix-org/synapse/issues/11515))
- Remove unnecessary `json.dumps` from `tests.rest.admin`. ([\#11461](https://github.com/matrix-org/synapse/issues/11461))
- Save the OpenID Connect session ID on login. ([\#11482](https://github.com/matrix-org/synapse/issues/11482))
- Update and clean up recently ported documentation pages. ([\#11466](https://github.com/matrix-org/synapse/issues/11466))

This reverts commit 158d73eb.

`COUNT()` never returns `NULL`. A `COUNT(*)` over 0 rows is 0 and a
`COUNT(NULL)` is also 0.

A couple of safety-checks to hopefully stop people doing what I just did, and create a storage
function which only works the first time it is called (and not when it is re-run due to a database
concurrency error or similar). 

* Splits the logic for parsing HTML from the resource handling code.
* Fix a circular import in the oEmbed code (which uses the HTML parsing code).
* Renames some of the HTML parsing methods to:
  * Make it clear which methods are "internal" to the module.
  * Clarify what the methods do.

Make `get_device` return None if the device doesn't exist rather than raising an exception. (#11565)

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

The event still needs to have `auth_events` defined to be valid.

Split out from https://github.com/matrix-org/synapse/pull/11114

Part of MSC2716: https://github.com/matrix-org/matrix-doc/pull/2716

We did some work on making sure the `state_groups` were shared in
https://github.com/matrix-org/synapse/pull/10975

C.f. https://github.com/matrix-org/synapse/pull/11494#pullrequestreview-827780886

Create a new dict helper method `simple_insert_many_values_txn`, which takes
raw row values, rather than {key=>value} dicts. This saves us a bunch of dict
munging, and makes it easier to use generators rather than creating
intermediate lists and dicts.

this field is never read, so we may as well stop populating it.

This should fix pushers with an email in non-canonical form is used as
the pushkey.