Merge tag 'v1.13.0'

Synapse 1.13.0 (2020-05-19)
===========================

This release brings some potential changes necessary for certain
configurations of Synapse:

* If your Synapse is configured to use SSO and have a custom
  `sso_redirect_confirm_template_dir` configuration option set, you will need
  to duplicate the new `sso_auth_confirm.html`, `sso_auth_success.html` and
  `sso_account_deactivated.html` templates into that directory.
* Synapse plugins using the `complete_sso_login` method of
  `synapse.module_api.ModuleApi` should instead switch to the async/await
  version, `complete_sso_login_async`, which includes additional checks. The
  former version is now deprecated.
* A bug was introduced in Synapse 1.4.0 which could cause the room directory
  to be incomplete or empty if Synapse was upgraded directly from v1.2.1 or
  earlier, to versions between v1.4.0 and v1.12.x.

Please review [UPGRADE.rst](https://github.com/matrix-org/synapse/blob/master/UPGRADE.rst)
for more details on these changes and for general upgrade guidance.

Notice of change to the default `git` branch for Synapse
--------------------------------------------------------

With the release of Synapse 1.13.0, the default `git` branch for Synapse has
changed to `develop`, which is the development tip. This is more consistent with
common practice and modern `git` usage.

The `master` branch, which tracks the latest release, is still available. It is
recommended that developers and distributors who have scripts which run builds
using the default branch of Synapse should therefore consider pinning their
scripts to `master`.

Features
--------

- Extend the `web_client_location` option to accept an absolute URL to use as a redirect. Adds a warning when running the web client on the same hostname as homeserver. Contributed by Martin Milata. ([\#7006](https://github.com/matrix-org/synapse/issues/7006))
- Set `Referrer-Policy` header to `no-referrer` on media downloads. ([\#7009](https://github.com/matrix-org/synapse/issues/7009))
- Add support for running replication over Redis when using workers. ([\#7040](https://github.com/matrix-org/synapse/issues/7040), [\#7325](https://github.com/matrix-org/synapse/issues/7325), [\#7352](https://github.com/matrix-org/synapse/issues/7352), [\#7401](https://github.com/matrix-org/synapse/issues/7401), [\#7427](https://github.com/matrix-org/synapse/issues/7427), [\#7439](https://github.com/matrix-org/synapse/issues/7439), [\#7446](https://github.com/matrix-org/synapse/issues/7446), [\#7450](https://github.com/matrix-org/synapse/issues/7450), [\#7454](https://github.com/matrix-org/synapse/issues/7454))
- Admin API `POST /_synapse/admin/v1/join/<roomIdOrAlias>` to join users to a room like `auto_join_rooms` for creation of users. ([\#7051](https://github.com/matrix-org/synapse/issues/7051))
- Add options to prevent users from changing their profile or associated 3PIDs. ([\#7096](https://github.com/matrix-org/synapse/issues/7096))
- Support SSO in the user interactive authentication workflow. ([\#7102](https://github.com/matrix-org/synapse/issues/7102), [\#7186](https://github.com/matrix-org/synapse/issues/7186), [\#7279](https://github.com/matrix-org/synapse/issues/7279), [\#7343](https://github.com/matrix-org/synapse/issues/7343))
- Allow server admins to define and enforce a password policy ([MSC2000](https://github.com/matrix-org/matrix-doc/issues/2000)). ([\#7118](https://github.com/matrix-org/synapse/issues/7118))
- Improve the support for SSO authentication on the login fallback page. ([\#7152](https://github.com/matrix-org/synapse/issues/7152), [\#7235](https://github.com/matrix-org/synapse/issues/7235))
- Always whitelist the login fallback in the SSO configuration if `public_baseurl` is set. ([\#7153](https://github.com/matrix-org/synapse/issues/7153))
- Admin users are no longer required to be in a room to create an alias for it. ([\#7191](https://github.com/matrix-org/synapse/issues/7191))
- Require admin privileges to enable room encryption by default. This does not affect existing rooms. ([\#7230](https://github.com/matrix-org/synapse/issues/7230))
- Add a config option for specifying the value of the Accept-Language HTTP header when generating URL previews. ([\#7265](https://github.com/matrix-org/synapse/issues/7265))
- Allow `/requestToken` endpoints to hide the existence (or lack thereof) of 3PID associations on the homeserver. ([\#7315](https://github.com/matrix-org/synapse/issues/7315))
- Add a configuration setting to tweak the threshold for dummy events. ([\#7422](https://github.com/matrix-org/synapse/issues/7422))

Bugfixes
--------

- Don't attempt to use an invalid sqlite config if no database configuration is provided. Contributed by @nekatak. ([\#6573](https://github.com/matrix-org/synapse/issues/6573))
- Fix single-sign on with CAS systems: pass the same service URL when requesting the CAS ticket and when calling the `proxyValidate` URL. Contributed by @Naugrimm. ([\#6634](https://github.com/matrix-org/synapse/issues/6634))
- Fix missing field `default` when fetching user-defined push rules. ([\#6639](https://github.com/matrix-org/synapse/issues/6639))
- Improve error responses when accessing remote public room lists. ([\#6899](https://github.com/matrix-org/synapse/issues/6899), [\#7368](https://github.com/matrix-org/synapse/issues/7368))
- Transfer alias mappings on room upgrade. ([\#6946](https://github.com/matrix-org/synapse/issues/6946))
- Ensure that a user interactive authentication session is tied to a single request. ([\#7068](https://github.com/matrix-org/synapse/issues/7068), [\#7455](https://github.com/matrix-org/synapse/issues/7455))
- Fix a bug in the federation API which could cause occasional "Failed to get PDU" errors. ([\#7089](https://github.com/matrix-org/synapse/issues/7089))
- Return the proper error (`M_BAD_ALIAS`) when a non-existant canonical alias is provided. ([\#7109](https://github.com/matrix-org/synapse/issues/7109))
- Fix a bug which meant that groups updates were not correctly replicated between workers. ([\#7117](https://github.com/matrix-org/synapse/issues/7117))
- Fix starting workers when federation sending not split out. ([\#7133](https://github.com/matrix-org/synapse/issues/7133))
- Ensure `is_verified` is a boolean in responses to `GET /_matrix/client/r0/room_keys/keys`. Also warn the user if they forgot the `version` query param. ([\#7150](https://github.com/matrix-org/synapse/issues/7150))
- Fix error page being shown when a custom SAML handler attempted to redirect when processing an auth response. ([\#7151](https://github.com/matrix-org/synapse/issues/7151))
- Avoid importing `sqlite3` when using the postgres backend. Contributed by David Vo. ([\#7155](https://github.com/matrix-org/synapse/issues/7155))
- Fix excessive CPU usage by `prune_old_outbound_device_pokes` job. ([\#7159](https://github.com/matrix-org/synapse/issues/7159))
- Fix a bug which could cause outbound federation traffic to stop working if a client uploaded an incorrect e2e device signature. ([\#7177](https://github.com/matrix-org/synapse/issues/7177))
- Fix a bug which could cause incorrect 'cyclic dependency' error. ([\#7178](https://github.com/matrix-org/synapse/issues/7178))
- Fix a bug that could cause a user to be invited to a server notices (aka System Alerts) room without any notice being sent. ([\#7199](https://github.com/matrix-org/synapse/issues/7199))
- Fix some worker-mode replication handling not being correctly recorded in CPU usage stats. ([\#7203](https://github.com/matrix-org/synapse/issues/7203))
- Do not allow a deactivated user to login via SSO. ([\#7240](https://github.com/matrix-org/synapse/issues/7240), [\#7259](https://github.com/matrix-org/synapse/issues/7259))
- Fix --help command-line argument. ([\#7249](https://github.com/matrix-org/synapse/issues/7249))
- Fix room publish permissions not being checked on room creation. ([\#7260](https://github.com/matrix-org/synapse/issues/7260))
- Reject unknown session IDs during user interactive authentication instead of silently creating a new session. ([\#7268](https://github.com/matrix-org/synapse/issues/7268))
- Fix a SQL query introduced in Synapse 1.12.0 which could cause large amounts of logging to the postgres slow-query log. ([\#7274](https://github.com/matrix-org/synapse/issues/7274))
- Persist user interactive authentication sessions across workers and Synapse restarts. ([\#7302](https://github.com/matrix-org/synapse/issues/7302))
- Fixed backwards compatibility logic of the first value of `trusted_third_party_id_servers` being used for `account_threepid_delegates.email`, which occurs when the former, deprecated option is set and the latter is not. ([\#7316](https://github.com/matrix-org/synapse/issues/7316))
- Fix a bug where event updates might not be sent over replication to worker processes after the stream falls behind. ([\#7337](https://github.com/matrix-org/synapse/issues/7337), [\#7358](https://github.com/matrix-org/synapse/issues/7358))
- Fix bad error handling that would cause Synapse to crash if it's provided with a YAML configuration file that's either empty or doesn't parse into a key-value map. ([\#7341](https://github.com/matrix-org/synapse/issues/7341))
- Fix incorrect metrics reporting for `renew_attestations` background task. ([\#7344](https://github.com/matrix-org/synapse/issues/7344))
- Prevent non-federating rooms from appearing in responses to federated `POST /publicRoom` requests when a filter was included. ([\#7367](https://github.com/matrix-org/synapse/issues/7367))
- Fix a bug which would cause the room durectory to be incorrectly populated if Synapse was upgraded directly from v1.2.1 or earlier to v1.4.0 or later. Note that this fix does not apply retrospectively; see the [upgrade notes](UPGRADE.rst#upgrading-to-v1130) for more information. ([\#7387](https://github.com/matrix-org/synapse/issues/7387))
- Fix bug in `EventContext.deserialize`. ([\#7393](https://github.com/matrix-org/synapse/issues/7393))
- Fix a long-standing bug which could cause messages not to be sent over federation, when state events with state keys matching user IDs (such as custom user statuses) were received. ([\#7376](https://github.com/matrix-org/synapse/issues/7376))
- Restore compatibility with non-compliant clients during the user interactive authentication process, fixing a problem introduced in v1.13.0rc1. ([\#7483](https://github.com/matrix-org/synapse/issues/7483))
- Hash passwords as early as possible during registration. ([\#7523](https://github.com/matrix-org/synapse/issues/7523))

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

- Update Debian installation instructions to recommend installing the `virtualenv` package instead of `python3-virtualenv`. ([\#6892](https://github.com/matrix-org/synapse/issues/6892))
- Improve the documentation for database configuration. ([\#6988](https://github.com/matrix-org/synapse/issues/6988))
- Improve the documentation of application service configuration files. ([\#7091](https://github.com/matrix-org/synapse/issues/7091))
- Update pre-built package name for FreeBSD. ([\#7107](https://github.com/matrix-org/synapse/issues/7107))
- Update postgres docs with login troubleshooting information. ([\#7119](https://github.com/matrix-org/synapse/issues/7119))
- Clean up INSTALL.md a bit. ([\#7141](https://github.com/matrix-org/synapse/issues/7141))
- Add documentation for running a local CAS server for testing. ([\#7147](https://github.com/matrix-org/synapse/issues/7147))
- Improve README.md by being explicit about public IP recommendation for TURN relaying. ([\#7167](https://github.com/matrix-org/synapse/issues/7167))
- Fix a small typo in the `metrics_flags` config option. ([\#7171](https://github.com/matrix-org/synapse/issues/7171))
- Update the contributed documentation on managing synapse workers with systemd, and bring it into the core distribution. ([\#7234](https://github.com/matrix-org/synapse/issues/7234))
- Add documentation to the `password_providers` config option. Add known password provider implementations to docs. ([\#7238](https://github.com/matrix-org/synapse/issues/7238), [\#7248](https://github.com/matrix-org/synapse/issues/7248))
- Modify suggested nginx reverse proxy configuration to match Synapse's default file upload size. Contributed by @ProCycleDev. ([\#7251](https://github.com/matrix-org/synapse/issues/7251))
- Documentation of media_storage_providers options updated to avoid misunderstandings. Contributed by Tristan Lins. ([\#7272](https://github.com/matrix-org/synapse/issues/7272))
- Add documentation on monitoring workers with Prometheus. ([\#7357](https://github.com/matrix-org/synapse/issues/7357))
- Clarify endpoint usage in the users admin api documentation. ([\#7361](https://github.com/matrix-org/synapse/issues/7361))

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

- Remove nonfunctional `captcha_bypass_secret` option from `homeserver.yaml`. ([\#7137](https://github.com/matrix-org/synapse/issues/7137))

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

- Add benchmarks for LruCache. ([\#6446](https://github.com/matrix-org/synapse/issues/6446))
- Return total number of users and profile attributes in admin users endpoint. Contributed by Awesome Technologies Innovationslabor GmbH. ([\#6881](https://github.com/matrix-org/synapse/issues/6881))
- Change device list streams to have one row per ID. ([\#7010](https://github.com/matrix-org/synapse/issues/7010))
- Remove concept of a non-limited stream. ([\#7011](https://github.com/matrix-org/synapse/issues/7011))
- Move catchup of replication streams logic to worker. ([\#7024](https://github.com/matrix-org/synapse/issues/7024), [\#7195](https://github.com/matrix-org/synapse/issues/7195), [\#7226](https://github.com/matrix-org/synapse/issues/7226), [\#7239](https://github.com/matrix-org/synapse/issues/7239), [\#7286](https://github.com/matrix-org/synapse/issues/7286), [\#7290](https://github.com/matrix-org/synapse/issues/7290), [\#7318](https://github.com/matrix-org/synapse/issues/7318), [\#7326](https://github.com/matrix-org/synapse/issues/7326), [\#7378](https://github.com/matrix-org/synapse/issues/7378), [\#7421](https://github.com/matrix-org/synapse/issues/7421))
- Convert some of synapse.rest.media to async/await. ([\#7110](https://github.com/matrix-org/synapse/issues/7110), [\#7184](https://github.com/matrix-org/synapse/issues/7184), [\#7241](https://github.com/matrix-org/synapse/issues/7241))
- De-duplicate / remove unused REST code for login and auth. ([\#7115](https://github.com/matrix-org/synapse/issues/7115))
- Convert `*StreamRow` classes to inner classes. ([\#7116](https://github.com/matrix-org/synapse/issues/7116))
- Clean up some LoggingContext code. ([\#7120](https://github.com/matrix-org/synapse/issues/7120), [\#7181](https://github.com/matrix-org/synapse/issues/7181), [\#7183](https://github.com/matrix-org/synapse/issues/7183), [\#7408](https://github.com/matrix-org/synapse/issues/7408), [\#7426](https://github.com/matrix-org/synapse/issues/7426))
- Add explicit `instance_id` for USER_SYNC commands and remove implicit `conn_id` usage. ([\#7128](https://github.com/matrix-org/synapse/issues/7128))
- Refactored the CAS authentication logic to a separate class. ([\#7136](https://github.com/matrix-org/synapse/issues/7136))
- Run replication streamers on workers. ([\#7146](https://github.com/matrix-org/synapse/issues/7146))
- Add tests for outbound device pokes. ([\#7157](https://github.com/matrix-org/synapse/issues/7157))
- Fix device list update stream ids going backward. ([\#7158](https://github.com/matrix-org/synapse/issues/7158))
- Use `stream.current_token()` and remove `stream_positions()`. ([\#7172](https://github.com/matrix-org/synapse/issues/7172))
- Move client command handling out of TCP protocol. ([\#7185](https://github.com/matrix-org/synapse/issues/7185))
- Move server command handling out of TCP protocol. ([\#7187](https://github.com/matrix-org/synapse/issues/7187))
- Fix consistency of HTTP status codes reported in log lines. ([\#7188](https://github.com/matrix-org/synapse/issues/7188))
- Only run one background database update at a time. ([\#7190](https://github.com/matrix-org/synapse/issues/7190))
- Remove sent outbound device list pokes from the database. ([\#7192](https://github.com/matrix-org/synapse/issues/7192))
- Add a background database update job to clear out duplicate `device_lists_outbound_pokes`. ([\#7193](https://github.com/matrix-org/synapse/issues/7193))
- Remove some extraneous debugging log lines. ([\#7207](https://github.com/matrix-org/synapse/issues/7207))
- Add explicit Python build tooling as dependencies for the snapcraft build. ([\#7213](https://github.com/matrix-org/synapse/issues/7213))
- Add typing information to federation server code. ([\#7219](https://github.com/matrix-org/synapse/issues/7219))
- Extend room admin api (`GET /_synapse/admin/v1/rooms`) with additional attributes. ([\#7225](https://github.com/matrix-org/synapse/issues/7225))
- Unblacklist '/upgrade creates a new room' sytest for workers. ([\#7228](https://github.com/matrix-org/synapse/issues/7228))
- Remove redundant checks on `daemonize` from synctl. ([\#7233](https://github.com/matrix-org/synapse/issues/7233))
- Upgrade jQuery to v3.4.1 on fallback login/registration pages. ([\#7236](https://github.com/matrix-org/synapse/issues/7236))
- Change log line that told user to implement onLogin/onRegister fallback js functions to a warning, instead of an info, so it's more visible. ([\#7237](https://github.com/matrix-org/synapse/issues/7237))
- Correct the parameters of a test fixture. Contributed by Isaiah Singletary. ([\#7243](https://github.com/matrix-org/synapse/issues/7243))
- Convert auth handler to async/await. ([\#7261](https://github.com/matrix-org/synapse/issues/7261))
- Add some unit tests for replication. ([\#7278](https://github.com/matrix-org/synapse/issues/7278))
- Improve typing annotations in `synapse.replication.tcp.streams.Stream`. ([\#7291](https://github.com/matrix-org/synapse/issues/7291))
- Reduce log verbosity of url cache cleanup tasks. ([\#7295](https://github.com/matrix-org/synapse/issues/7295))
- Fix sample SAML Service Provider configuration. Contributed by @frcl. ([\#7300](https://github.com/matrix-org/synapse/issues/7300))
- Fix StreamChangeCache to work with multiple entities changing on the same stream id. ([\#7303](https://github.com/matrix-org/synapse/issues/7303))
- Fix an incorrect import in IdentityHandler. ([\#7319](https://github.com/matrix-org/synapse/issues/7319))
- Reduce logging verbosity for successful federation requests. ([\#7321](https://github.com/matrix-org/synapse/issues/7321))
- Convert some federation handler code to async/await. ([\#7338](https://github.com/matrix-org/synapse/issues/7338))
- Fix collation for postgres for unit tests. ([\#7359](https://github.com/matrix-org/synapse/issues/7359))
- Convert RegistrationWorkerStore.is_server_admin and dependent code to async/await. ([\#7363](https://github.com/matrix-org/synapse/issues/7363))
- Add an `instance_name` to `RDATA` and `POSITION` replication commands. ([\#7364](https://github.com/matrix-org/synapse/issues/7364))
- Thread through instance name to replication client. ([\#7369](https://github.com/matrix-org/synapse/issues/7369))
- Convert synapse.server_notices to async/await. ([\#7394](https://github.com/matrix-org/synapse/issues/7394))
- Convert synapse.notifier to async/await. ([\#7395](https://github.com/matrix-org/synapse/issues/7395))
- Fix issues with the Python package manifest. ([\#7404](https://github.com/matrix-org/synapse/issues/7404))
- Prevent methods in `synapse.handlers.auth` from polling the homeserver config every request. ([\#7420](https://github.com/matrix-org/synapse/issues/7420))
- Speed up fetching device lists changes when handling `/sync` requests. ([\#7423](https://github.com/matrix-org/synapse/issues/7423))
- Run group attestation renewal in series rather than parallel for performance. ([\#7442](https://github.com/matrix-org/synapse/issues/7442))
- Fix linting errors in new version of Flake8. ([\#7470](https://github.com/matrix-org/synapse/issues/7470))
- Update the version of dh-virtualenv we use to build debs, and add focal to the list of target distributions. ([\#7526](https://github.com/matrix-org/synapse/issues/7526))

4 files changed, 82 insertions, 63 deletions

diff --git a/synapse/server_notices/consent_server_notices.py b/synapse/server_notices/consent_server_notices.py
index 5736c56032..3bf330da49 100644
--- a/synapse/server_notices/consent_server_notices.py
+++ b/synapse/server_notices/consent_server_notices.py
@@ -16,8 +16,6 @@ import logging
 
 from six import iteritems, string_types
 
-from twisted.internet import defer
-
 from synapse.api.errors import SynapseError
 from synapse.api.urls import ConsentURIBuilder
 from synapse.config import ConfigError
@@ -59,8 +57,7 @@ class ConsentServerNotices(object):
 
             self._consent_uri_builder = ConsentURIBuilder(hs.config)
 
-    @defer.inlineCallbacks
-    def maybe_send_server_notice_to_user(self, user_id):
+    async def maybe_send_server_notice_to_user(self, user_id):
         """Check if we need to send a notice to this user, and does so if so
 
         Args:
@@ -78,7 +75,7 @@ class ConsentServerNotices(object):
             return
         self._users_in_progress.add(user_id)
         try:
-            u = yield self._store.get_user_by_id(user_id)
+            u = await self._store.get_user_by_id(user_id)
 
             if u["is_guest"] and not self._send_to_guests:
                 # don't send to guests
@@ -100,8 +97,8 @@ class ConsentServerNotices(object):
                 content = copy_with_str_subst(
                     self._server_notice_content, {"consent_uri": consent_uri}
                 )
-                yield self._server_notices_manager.send_notice(user_id, content)
-                yield self._store.user_set_consent_server_notice_sent(
+                await self._server_notices_manager.send_notice(user_id, content)
+                await self._store.user_set_consent_server_notice_sent(
                     user_id, self._current_consent_version
                 )
             except SynapseError as e:
diff --git a/synapse/server_notices/resource_limits_server_notices.py b/synapse/server_notices/resource_limits_server_notices.py
index 9fae2e0afe..d97166351e 100644
--- a/synapse/server_notices/resource_limits_server_notices.py
+++ b/synapse/server_notices/resource_limits_server_notices.py
@@ -16,8 +16,6 @@ import logging
 
 from six import iteritems
 
-from twisted.internet import defer
-
 from synapse.api.constants import (
     EventTypes,
     LimitBlockingTypes,
@@ -50,8 +48,7 @@ class ResourceLimitsServerNotices(object):
 
         self._notifier = hs.get_notifier()
 
-    @defer.inlineCallbacks
-    def maybe_send_server_notice_to_user(self, user_id):
+    async def maybe_send_server_notice_to_user(self, user_id):
         """Check if we need to send a notice to this user, this will be true in
         two cases.
         1. The server has reached its limit does not reflect this
@@ -74,22 +71,24 @@ class ResourceLimitsServerNotices(object):
             # Don't try and send server notices unless they've been enabled
             return
 
-        timestamp = yield self._store.user_last_seen_monthly_active(user_id)
+        timestamp = await self._store.user_last_seen_monthly_active(user_id)
         if timestamp is None:
             # This user will be blocked from receiving the notice anyway.
             # In practice, not sure we can ever get here
             return
 
-        room_id = yield self._server_notices_manager.get_notice_room_for_user(user_id)
+        room_id = await self._server_notices_manager.get_or_create_notice_room_for_user(
+            user_id
+        )
 
         if not room_id:
             logger.warning("Failed to get server notices room")
             return
 
-        yield self._check_and_set_tags(user_id, room_id)
+        await self._check_and_set_tags(user_id, room_id)
 
         # Determine current state of room
-        currently_blocked, ref_events = yield self._is_room_currently_blocked(room_id)
+        currently_blocked, ref_events = await self._is_room_currently_blocked(room_id)
 
         limit_msg = None
         limit_type = None
@@ -97,7 +96,7 @@ class ResourceLimitsServerNotices(object):
             # Normally should always pass in user_id to check_auth_blocking
             # if you have it, but in this case are checking what would happen
             # to other users if they were to arrive.
-            yield self._auth.check_auth_blocking()
+            await self._auth.check_auth_blocking()
         except ResourceLimitError as e:
             limit_msg = e.msg
             limit_type = e.limit_type
@@ -110,22 +109,21 @@ class ResourceLimitsServerNotices(object):
                 # We have hit the MAU limit, but MAU alerting is disabled:
                 # reset room if necessary and return
                 if currently_blocked:
-                    self._remove_limit_block_notification(user_id, ref_events)
+                    await self._remove_limit_block_notification(user_id, ref_events)
                 return
 
             if currently_blocked and not limit_msg:
                 # Room is notifying of a block, when it ought not to be.
-                yield self._remove_limit_block_notification(user_id, ref_events)
+                await self._remove_limit_block_notification(user_id, ref_events)
             elif not currently_blocked and limit_msg:
                 # Room is not notifying of a block, when it ought to be.
-                yield self._apply_limit_block_notification(
+                await self._apply_limit_block_notification(
                     user_id, limit_msg, limit_type
                 )
         except SynapseError as e:
             logger.error("Error sending resource limits server notice: %s", e)
 
-    @defer.inlineCallbacks
-    def _remove_limit_block_notification(self, user_id, ref_events):
+    async def _remove_limit_block_notification(self, user_id, ref_events):
         """Utility method to remove limit block notifications from the server
         notices room.
 
@@ -135,12 +133,13 @@ class ResourceLimitsServerNotices(object):
             limit blocking and need to be preserved.
         """
         content = {"pinned": ref_events}
-        yield self._server_notices_manager.send_notice(
+        await self._server_notices_manager.send_notice(
             user_id, content, EventTypes.Pinned, ""
         )
 
-    @defer.inlineCallbacks
-    def _apply_limit_block_notification(self, user_id, event_body, event_limit_type):
+    async def _apply_limit_block_notification(
+        self, user_id, event_body, event_limit_type
+    ):
         """Utility method to apply limit block notifications in the server
         notices room.
 
@@ -157,17 +156,16 @@ class ResourceLimitsServerNotices(object):
             "admin_contact": self._config.admin_contact,
             "limit_type": event_limit_type,
         }
-        event = yield self._server_notices_manager.send_notice(
+        event = await self._server_notices_manager.send_notice(
             user_id, content, EventTypes.Message
         )
 
         content = {"pinned": [event.event_id]}
-        yield self._server_notices_manager.send_notice(
+        await self._server_notices_manager.send_notice(
             user_id, content, EventTypes.Pinned, ""
         )
 
-    @defer.inlineCallbacks
-    def _check_and_set_tags(self, user_id, room_id):
+    async def _check_and_set_tags(self, user_id, room_id):
         """
         Since server notices rooms were originally not with tags,
         important to check that tags have been set correctly
@@ -175,20 +173,19 @@ class ResourceLimitsServerNotices(object):
             user_id(str): the user in question
             room_id(str): the server notices room for that user
         """
-        tags = yield self._store.get_tags_for_room(user_id, room_id)
+        tags = await self._store.get_tags_for_room(user_id, room_id)
         need_to_set_tag = True
         if tags:
             if SERVER_NOTICE_ROOM_TAG in tags:
                 # tag already present, nothing to do here
                 need_to_set_tag = False
         if need_to_set_tag:
-            max_id = yield self._store.add_tag_to_room(
+            max_id = await self._store.add_tag_to_room(
                 user_id, room_id, SERVER_NOTICE_ROOM_TAG, {}
             )
             self._notifier.on_new_event("account_data_key", max_id, users=[user_id])
 
-    @defer.inlineCallbacks
-    def _is_room_currently_blocked(self, room_id):
+    async def _is_room_currently_blocked(self, room_id):
         """
         Determines if the room is currently blocked
 
@@ -196,7 +193,7 @@ class ResourceLimitsServerNotices(object):
             room_id(str): The room id of the server notices room
 
         Returns:
-
+            Deferred[Tuple[bool, List]]:
             bool: Is the room currently blocked
             list: The list of pinned events that are unrelated to limit blocking
             This list can be used as a convenience in the case where the block
@@ -206,7 +203,7 @@ class ResourceLimitsServerNotices(object):
         currently_blocked = False
         pinned_state_event = None
         try:
-            pinned_state_event = yield self._state.get_current_state(
+            pinned_state_event = await self._state.get_current_state(
                 room_id, event_type=EventTypes.Pinned
             )
         except AuthError:
@@ -217,7 +214,7 @@ class ResourceLimitsServerNotices(object):
         if pinned_state_event is not None:
             referenced_events = list(pinned_state_event.content.get("pinned", []))
 
-        events = yield self._store.get_events(referenced_events)
+        events = await self._store.get_events(referenced_events)
         for event_id, event in iteritems(events):
             if event.type != EventTypes.Message:
                 continue
diff --git a/synapse/server_notices/server_notices_manager.py b/synapse/server_notices/server_notices_manager.py
index f7432c8d2f..999c621b92 100644
--- a/synapse/server_notices/server_notices_manager.py
+++ b/synapse/server_notices/server_notices_manager.py
@@ -14,11 +14,9 @@
 # limitations under the License.
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.constants import EventTypes, Membership, RoomCreationPreset
-from synapse.types import create_requester
-from synapse.util.caches.descriptors import cachedInlineCallbacks
+from synapse.types import UserID, create_requester
+from synapse.util.caches.descriptors import cached
 
 logger = logging.getLogger(__name__)
 
@@ -36,10 +34,12 @@ class ServerNoticesManager(object):
         self._store = hs.get_datastore()
         self._config = hs.config
         self._room_creation_handler = hs.get_room_creation_handler()
+        self._room_member_handler = hs.get_room_member_handler()
         self._event_creation_handler = hs.get_event_creation_handler()
         self._is_mine_id = hs.is_mine_id
 
         self._notifier = hs.get_notifier()
+        self.server_notices_mxid = self._config.server_notices_mxid
 
     def is_enabled(self):
         """Checks if server notices are enabled on this server.
@@ -49,8 +49,7 @@ class ServerNoticesManager(object):
         """
         return self._config.server_notices_mxid is not None
 
-    @defer.inlineCallbacks
-    def send_notice(
+    async def send_notice(
         self, user_id, event_content, type=EventTypes.Message, state_key=None
     ):
         """Send a notice to the given user
@@ -66,7 +65,8 @@ class ServerNoticesManager(object):
         Returns:
             Deferred[FrozenEvent]
         """
-        room_id = yield self.get_notice_room_for_user(user_id)
+        room_id = await self.get_or_create_notice_room_for_user(user_id)
+        await self.maybe_invite_user_to_room(user_id, room_id)
 
         system_mxid = self._config.server_notices_mxid
         requester = create_requester(system_mxid)
@@ -83,16 +83,17 @@ class ServerNoticesManager(object):
         if state_key is not None:
             event_dict["state_key"] = state_key
 
-        res = yield self._event_creation_handler.create_and_send_nonmember_event(
+        res = await self._event_creation_handler.create_and_send_nonmember_event(
             requester, event_dict, ratelimit=False
         )
         return res
 
-    @cachedInlineCallbacks()
-    def get_notice_room_for_user(self, user_id):
+    @cached()
+    async def get_or_create_notice_room_for_user(self, user_id):
         """Get the room for notices for a given user
 
-        If we have not yet created a notice room for this user, create it
+        If we have not yet created a notice room for this user, create it, but don't
+        invite the user to it.
 
         Args:
             user_id (str): complete user id for the user we want a room for
@@ -105,21 +106,24 @@ class ServerNoticesManager(object):
 
         assert self._is_mine_id(user_id), "Cannot send server notices to remote users"
 
-        rooms = yield self._store.get_rooms_for_local_user_where_membership_is(
+        rooms = await self._store.get_rooms_for_local_user_where_membership_is(
             user_id, [Membership.INVITE, Membership.JOIN]
         )
-        system_mxid = self._config.server_notices_mxid
         for room in rooms:
             # it's worth noting that there is an asymmetry here in that we
             # expect the user to be invited or joined, but the system user must
             # be joined. This is kinda deliberate, in that if somebody somehow
             # manages to invite the system user to a room, that doesn't make it
             # the server notices room.
-            user_ids = yield self._store.get_users_in_room(room.room_id)
-            if system_mxid in user_ids:
+            user_ids = await self._store.get_users_in_room(room.room_id)
+            if self.server_notices_mxid in user_ids:
                 # we found a room which our user shares with the system notice
                 # user
-                logger.info("Using room %s", room.room_id)
+                logger.info(
+                    "Using existing server notices room %s for user %s",
+                    room.room_id,
+                    user_id,
+                )
                 return room.room_id
 
         # apparently no existing notice room: create a new one
@@ -138,24 +142,49 @@ class ServerNoticesManager(object):
                 "avatar_url": self._config.server_notices_mxid_avatar_url,
             }
 
-        requester = create_requester(system_mxid)
-        info = yield self._room_creation_handler.create_room(
+        requester = create_requester(self.server_notices_mxid)
+        info = await self._room_creation_handler.create_room(
             requester,
             config={
                 "preset": RoomCreationPreset.PRIVATE_CHAT,
                 "name": self._config.server_notices_room_name,
                 "power_level_content_override": {"users_default": -10},
-                "invite": (user_id,),
             },
             ratelimit=False,
             creator_join_profile=join_profile,
         )
         room_id = info["room_id"]
 
-        max_id = yield self._store.add_tag_to_room(
+        max_id = await self._store.add_tag_to_room(
             user_id, room_id, SERVER_NOTICE_ROOM_TAG, {}
         )
         self._notifier.on_new_event("account_data_key", max_id, users=[user_id])
 
         logger.info("Created server notices room %s for %s", room_id, user_id)
         return room_id
+
+    async def maybe_invite_user_to_room(self, user_id: str, room_id: str):
+        """Invite the given user to the given server room, unless the user has already
+        joined or been invited to it.
+
+        Args:
+            user_id: The ID of the user to invite.
+            room_id: The ID of the room to invite the user to.
+        """
+        requester = create_requester(self.server_notices_mxid)
+
+        # Check whether the user has already joined or been invited to this room. If
+        # that's the case, there is no need to re-invite them.
+        joined_rooms = await self._store.get_rooms_for_local_user_where_membership_is(
+            user_id, [Membership.INVITE, Membership.JOIN]
+        )
+        for room in joined_rooms:
+            if room.room_id == room_id:
+                return
+
+        await self._room_member_handler.update_membership(
+            requester=requester,
+            target=UserID.from_string(user_id),
+            room_id=room_id,
+            action="invite",
+        )
diff --git a/synapse/server_notices/server_notices_sender.py b/synapse/server_notices/server_notices_sender.py
index 652bab58e3..be74e86641 100644
--- a/synapse/server_notices/server_notices_sender.py
+++ b/synapse/server_notices/server_notices_sender.py
@@ -12,8 +12,6 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from twisted.internet import defer
-
 from synapse.server_notices.consent_server_notices import ConsentServerNotices
 from synapse.server_notices.resource_limits_server_notices import (
     ResourceLimitsServerNotices,
@@ -36,18 +34,16 @@ class ServerNoticesSender(object):
             ResourceLimitsServerNotices(hs),
         )
 
-    @defer.inlineCallbacks
-    def on_user_syncing(self, user_id):
+    async def on_user_syncing(self, user_id):
         """Called when the user performs a sync operation.
 
         Args:
             user_id (str): mxid of user who synced
         """
         for sn in self._server_notices:
-            yield sn.maybe_send_server_notice_to_user(user_id)
+            await sn.maybe_send_server_notice_to_user(user_id)
 
-    @defer.inlineCallbacks
-    def on_user_ip(self, user_id):
+    async def on_user_ip(self, user_id):
         """Called on the master when a worker process saw a client request.
 
         Args:
@@ -57,4 +53,4 @@ class ServerNoticesSender(object):
         # we check for notices to send to the user in on_user_ip as well as
         # in on_user_syncing
         for sn in self._server_notices:
-            yield sn.maybe_send_server_notice_to_user(user_id)
+            await sn.maybe_send_server_notice_to_user(user_id)