This can happen when using a split out state database and we've upgraded
the schema version without there being any changes in the state schema.

Synapse 1.25.0rc1 (2021-01-06)
==============================

Removal warning
---------------

The old [Purge Room API](https://github.com/matrix-org/synapse/tree/master/docs/admin_api/purge_room.md)
and [Shutdown Room API](https://github.com/matrix-org/synapse/tree/master/docs/admin_api/shutdown_room.md)
are deprecated and will be removed in a future release. They will be replaced by the
[Delete Room API](https://github.com/matrix-org/synapse/tree/master/docs/admin_api/rooms.md#delete-room-api).

`POST /_synapse/admin/v1/rooms/<room_id>/delete` replaces `POST /_synapse/admin/v1/purge_room` and
`POST /_synapse/admin/v1/shutdown_room/<room_id>`.

Features
--------

- Add an admin API that lets server admins get power in rooms in which local users have power. ([\#8756](https://github.com/matrix-org/synapse/issues/8756))
- Add optional HTTP authentication to replication endpoints. ([\#8853](https://github.com/matrix-org/synapse/issues/8853))
- Improve the error messages printed as a result of configuration problems for extension modules. ([\#8874](https://github.com/matrix-org/synapse/issues/8874))
- Add the number of local devices to Room Details Admin API. Contributed by @dklimpel. ([\#8886](https://github.com/matrix-org/synapse/issues/8886))
- Add `X-Robots-Tag` header to stop web crawlers from indexing media. Contributed by Aaron Raimist. ([\#8887](https://github.com/matrix-org/synapse/issues/8887))
- Spam-checkers may now define their methods as `async`. ([\#8890](https://github.com/matrix-org/synapse/issues/8890))
- Add support for allowing users to pick their own user ID during a single-sign-on login. ([\#8897](https://github.com/matrix-org/synapse/issues/8897), [\#8900](https://github.com/matrix-org/synapse/issues/8900), [\#8911](https://github.com/matrix-org/synapse/issues/8911), [\#8938](https://github.com/matrix-org/synapse/issues/8938), [\#8941](https://github.com/matrix-org/synapse/issues/8941), [\#8942](https://github.com/matrix-org/synapse/issues/8942), [\#8951](https://github.com/matrix-org/synapse/issues/8951))
- Add an `email.invite_client_location` configuration option to send a web client location to the invite endpoint on the identity server which allows customisation of the email template. ([\#8930](https://github.com/matrix-org/synapse/issues/8930))
- The search term in the list room and list user Admin APIs is now treated as case-insensitive. ([\#8931](https://github.com/matrix-org/synapse/issues/8931))
- Apply an IP range blacklist to push and key revocation requests. ([\#8821](https://github.com/matrix-org/synapse/issues/8821), [\#8870](https://github.com/matrix-org/synapse/issues/8870), [\#8954](https://github.com/matrix-org/synapse/issues/8954))
- Add an option to allow re-use of user-interactive authentication sessions for a period of time. ([\#8970](https://github.com/matrix-org/synapse/issues/8970))
- Allow running the redact endpoint on workers. ([\#8994](https://github.com/matrix-org/synapse/issues/8994))

Bugfixes
--------

- Fix bug where we might not correctly calculate the current state for rooms with multiple extremities. ([\#8827](https://github.com/matrix-org/synapse/issues/8827))
- Fix a long-standing bug in the register admin endpoint (`/_synapse/admin/v1/register`) when the `mac` field was not provided. The endpoint now properly returns a 400 error. Contributed by @edwargix. ([\#8837](https://github.com/matrix-org/synapse/issues/8837))
- Fix a long-standing bug on Synapse instances supporting Single-Sign-On, where users would be prompted to enter their password to confirm certain actions, even though they have not set a password. ([\#8858](https://github.com/matrix-org/synapse/issues/8858))
- Fix a longstanding bug where a 500 error would be returned if the `Content-Length` header was not provided to the upload media resource. ([\#8862](https://github.com/matrix-org/synapse/issues/8862))
- Add additional validation to pusher URLs to be compliant with the specification. ([\#8865](https://github.com/matrix-org/synapse/issues/8865))
- Fix the error code that is returned when a user tries to register on a homeserver on which new-user registration has been disabled. ([\#8867](https://github.com/matrix-org/synapse/issues/8867))
- Fix a bug where `PUT /_synapse/admin/v2/users/<user_id>` failed to create a new user when `avatar_url` is specified. Bug introduced in Synapse v1.9.0. ([\#8872](https://github.com/matrix-org/synapse/issues/8872))
- Fix a 500 error when attempting to preview an empty HTML file. ([\#8883](https://github.com/matrix-org/synapse/issues/8883))
- Fix occasional deadlock when handling SIGHUP. ([\#8918](https://github.com/matrix-org/synapse/issues/8918))
- Fix login API to not ratelimit application services that have ratelimiting disabled. ([\#8920](https://github.com/matrix-org/synapse/issues/8920))
- Fix bug where we ratelimited auto joining of rooms on registration (using `auto_join_rooms` config). ([\#8921](https://github.com/matrix-org/synapse/issues/8921))
- Fix a bug where deactivated users appeared in the user directory when their profile information was updated. ([\#8933](https://github.com/matrix-org/synapse/issues/8933), [\#8964](https://github.com/matrix-org/synapse/issues/8964))
- Fix bug introduced in Synapse v1.24.0 which would cause an exception on startup if both `enabled` and `localdb_enabled` were set to `False` in the `password_config` setting of the configuration file. ([\#8937](https://github.com/matrix-org/synapse/issues/8937))
- Fix a bug where 500 errors would be returned if the `m.room_history_visibility` event had invalid content. ([\#8945](https://github.com/matrix-org/synapse/issues/8945))
- Fix a bug causing common English words to not be considered for a user directory search. ([\#8959](https://github.com/matrix-org/synapse/issues/8959))
- Fix bug where application services couldn't register new ghost users if the server had reached its MAU limit. ([\#8962](https://github.com/matrix-org/synapse/issues/8962))
- Fix a long-standing bug where a `m.image` event without a `url` would cause errors on push. ([\#8965](https://github.com/matrix-org/synapse/issues/8965))
- Fix a small bug in v2 state resolution algorithm, which could also cause performance issues for rooms with large numbers of power levels. ([\#8971](https://github.com/matrix-org/synapse/issues/8971))
- Add validation to the `sendToDevice` API to raise a missing parameters error instead of a 500 error. ([\#8975](https://github.com/matrix-org/synapse/issues/8975))
- Add validation of group IDs to raise a 400 error instead of a 500 eror. ([\#8977](https://github.com/matrix-org/synapse/issues/8977))

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

- Fix the "Event persist rate" section of the included grafana dashboard by adding missing prometheus rules. ([\#8802](https://github.com/matrix-org/synapse/issues/8802))
- Combine related media admin API docs. ([\#8839](https://github.com/matrix-org/synapse/issues/8839))
- Fix an error in the documentation for the SAML username mapping provider. ([\#8873](https://github.com/matrix-org/synapse/issues/8873))
- Clarify comments around template directories in `sample_config.yaml`. ([\#8891](https://github.com/matrix-org/synapse/issues/8891))
- Moved instructions for database setup, adjusted heading levels and improved syntax highlighting in [INSTALL.md](../INSTALL.md). Contributed by fossterer. ([\#8987](https://github.com/matrix-org/synapse/issues/8987))
- Update the example value of `group_creation_prefix` in the sample configuration. ([\#8992](https://github.com/matrix-org/synapse/issues/8992))
- Link the Synapse developer room to the development section in the docs. ([\#9002](https://github.com/matrix-org/synapse/issues/9002))

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

- Deprecate Shutdown Room and Purge Room Admin APIs. ([\#8829](https://github.com/matrix-org/synapse/issues/8829))

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

- Properly store the mapping of external ID to Matrix ID for CAS users. ([\#8856](https://github.com/matrix-org/synapse/issues/8856), [\#8958](https://github.com/matrix-org/synapse/issues/8958))
- Remove some unnecessary stubbing from unit tests. ([\#8861](https://github.com/matrix-org/synapse/issues/8861))
- Remove unused `FakeResponse` class from unit tests. ([\#8864](https://github.com/matrix-org/synapse/issues/8864))
- Pass `room_id` to `get_auth_chain_difference`. ([\#8879](https://github.com/matrix-org/synapse/issues/8879))
- Add type hints to push module. ([\#8880](https://github.com/matrix-org/synapse/issues/8880), [\#8882](https://github.com/matrix-org/synapse/issues/8882), [\#8901](https://github.com/matrix-org/synapse/issues/8901), [\#8940](https://github.com/matrix-org/synapse/issues/8940), [\#8943](https://github.com/matrix-org/synapse/issues/8943), [\#9020](https://github.com/matrix-org/synapse/issues/9020))
- Simplify logic for handling user-interactive-auth via single-sign-on servers. ([\#8881](https://github.com/matrix-org/synapse/issues/8881))
- Skip the SAML tests if the requirements (`pysaml2` and `xmlsec1`) aren't available. ([\#8905](https://github.com/matrix-org/synapse/issues/8905))
- Fix multiarch docker image builds. ([\#8906](https://github.com/matrix-org/synapse/issues/8906))
- Don't publish `latest` docker image until all archs are built. ([\#8909](https://github.com/matrix-org/synapse/issues/8909))
- Various clean-ups to the structured logging and logging context code. ([\#8916](https://github.com/matrix-org/synapse/issues/8916), [\#8935](https://github.com/matrix-org/synapse/issues/8935))
- Automatically drop stale forward-extremities under some specific conditions. ([\#8929](https://github.com/matrix-org/synapse/issues/8929))
- Refactor test utilities for injecting HTTP requests. ([\#8946](https://github.com/matrix-org/synapse/issues/8946))
- Add a maximum size of 50 kilobytes to .well-known lookups. ([\#8950](https://github.com/matrix-org/synapse/issues/8950))
- Fix bug in `generate_log_config` script which made it write empty files. ([\#8952](https://github.com/matrix-org/synapse/issues/8952))
- Clean up tox.ini file; disable coverage checking for non-test runs. ([\#8963](https://github.com/matrix-org/synapse/issues/8963))
- Add type hints to the admin and room list handlers. ([\#8973](https://github.com/matrix-org/synapse/issues/8973))
- Add type hints to the receipts and user directory handlers. ([\#8976](https://github.com/matrix-org/synapse/issues/8976))
- Drop the unused `local_invites` table. ([\#8979](https://github.com/matrix-org/synapse/issues/8979))
- Add type hints to the base storage code. ([\#8980](https://github.com/matrix-org/synapse/issues/8980))
- Support using PyJWT v2.0.0 in the test suite. ([\#8986](https://github.com/matrix-org/synapse/issues/8986))
- Fix `tests.federation.transport.RoomDirectoryFederationTests` and ensure it runs in CI. ([\#8998](https://github.com/matrix-org/synapse/issues/8998))
- Add type hints to the crypto module. ([\#8999](https://github.com/matrix-org/synapse/issues/8999))

These may be omitted if not set, but Synapse assumed they would
be in the response.

The last stream token is always known and we do not need to handle none.

Ex.

 - homeserver.log.2020-12-29
 - homeserver.log.2020-12-31

An experimental room version ("org.matrix.msc2176") contains
the new redaction rules for testing.

During login, if there are multiple IdPs enabled, offer the user a choice of
IdPs.

* Implement CasHandler.handle_redirect_request

... to make it match OidcHandler and SamlHandler

* Clean up interface for OidcHandler.handle_redirect_request

Make it accept `client_redirect_url=None`.

* Clean up interface for `SamlHandler.handle_redirect_request`

... bring it into line with CAS and OIDC by making it take a Request parameter,
move the magic for `client_redirect_url` for UIA into the handler, and fix the
return type to be a `str` rather than a `bytes`.

* Define a common protocol for SSO auth provider impls

* Give SsoIdentityProvider an ID and register them

* Combine the SSO Redirect servlets

Now that the SsoHandler knows about the identity providers, we can combine the
various *RedirectServlets into a single implementation which delegates to the
right IdP.

* changelog

The `RoomDirectoryFederationTests` tests were not being run unless explicitly called as an `__init__.py` file was not present in `tests/federation/transport/`. Thus the folder was not a python module, and `trial` did not look inside for any test cases to run. This was found while working on #6739.

This PR adds a `__init__.py` and also fixes the test in a couple ways:

- Switch to subclassing `unittest.FederatingHomeserverTestCase` instead, which sets up federation endpoints for us.
- Supply a `federation_auth_origin` to `make_request` in order to more act like the request is coming from another server, instead of just an unauthenicated client requesting a federation endpoint.

I found that the second point makes no difference to the test passing, but felt like the right thing to do if we're testing over federation.

This makes the "messages" key in the content required. This is currently
optional in the spec, but that seems to be an error.

Removes the trailing slash with causes issues with matrix.to/Element.

Adds the redacts endpoint to workers that have the client listener.

This table has been unused since Synapse v1.17.0.

Tests were broken due to an API changing. The code used in Synapse
proper should be compatible with both versions already.

This makes the CAS handler look more like the SAML/OIDC handlers:

* Render errors to users instead of throwing JSON errors.
* Internal reorganization.

Adds a new setting `email.invite_client_location` which, if defined, is
passed to the identity server during invites.

This adds an admin API that allows a server admin to get power in a room if a local user has power in a room. Will also invite the user if they're not in the room and its a private room. Can specify another user (rather than the admin user) to be granted power.

Co-authored-by: Matthew Hodgson <matthew@matrix.org>

This had two effects 1) it'd give the wrong answer and b) would iterate
*all* power levels in the auth chain of each event. The latter of which
can be *very* expensive for certain types of IRC bridge rooms that have
large numbers of power level changes.

The final part (for now) of my work to implement a username picker in synapse itself. The idea is that we allow
`UsernameMappingProvider`s to return `localpart=None`, in which case, rather than redirecting the browser
back to the client, we redirect to a username-picker resource, which allows the user to enter a username.
We *then* complete the SSO flow (including doing the client permission checks).

The static resources for the username picker itself (in 
https://github.com/matrix-org/synapse/tree/rav/username_picker/synapse/res/username_picker)
are essentially lifted wholesale from
https://github.com/matrix-org/matrix-synapse-saml-mozilla/tree/master/matrix_synapse_saml_mozilla/res. 
As the comment says, we might want to think about making them customisable, but that can be a follow-up. 

Fixes #8876.

This fixes an KeyError exception, after this PR the content
is just considered unknown.

If we see stale extremities while persisting events, and notice that
they don't change the result of state resolution, we drop them.

... and disable coverage tracking for mypy and friends.

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