Merge remote-tracking branch 'upstream/release-v1.63'

2024-06-29 16:08:21 +02:00 · 2022-07-12 14:31:20 +03:00 · 2022-07-12 14:31:20 +03:00 · a026581985
parent d0f49d2935 6173d585df
commit a026581985
106 changed files with 3262 additions and 1370 deletions
--- a/.ci/scripts/setup_complement_prerequisites.sh
+++ b/.ci/scripts/setup_complement_prerequisites.sh
@ -0,0 +1,36 @@
+#!/bin/sh
+#
+# Common commands to set up Complement's prerequisites in a GitHub Actions CI run.
+#
+# Must be called after Synapse has been checked out to `synapse/`.
+#
+set -eu
+
+alias block='{ set +x; } 2>/dev/null; func() { echo "::group::$*"; set -x; }; func'
+alias endblock='{ set +x; } 2>/dev/null; func() { echo "::endgroup::"; set -x; }; func'
+
+block Set Go Version
+  # The path is set via a file given by $GITHUB_PATH. We need both Go 1.17 and GOPATH on the path to run Complement.
+  # See https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#adding-a-system-path
+
+  # Add Go 1.17 to the PATH: see https://github.com/actions/virtual-environments/blob/main/images/linux/Ubuntu2004-Readme.md#environment-variables-2
+  echo "$GOROOT_1_17_X64/bin" >> $GITHUB_PATH
+  # Add the Go path to the PATH: We need this so we can call gotestfmt
+  echo "~/go/bin" >> $GITHUB_PATH
+endblock
+
+block Install Complement Dependencies
+  sudo apt-get -qq update && sudo apt-get install -qqy libolm3 libolm-dev
+  go get -v github.com/haveyoudebuggedit/gotestfmt/v2/cmd/gotestfmt@latest
+endblock
+
+block Install custom gotestfmt template
+  mkdir .gotestfmt/github -p
+  cp synapse/.ci/complement_package.gotpl .gotestfmt/github/package.gotpl
+endblock
+
+block Check out Complement
+  # Attempt to check out the same branch of Complement as the PR. If it
+  # doesn't exist, fallback to HEAD.
+  synapse/.ci/scripts/checkout_complement.sh
+endblock
--- a/.editorconfig
+++ b/.editorconfig
@ -7,3 +7,4 @@ root = true
 [*.py]
 indent_style = space
 indent_size = 4
+max_line_length = 88
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@ -328,85 +328,21 @@ jobs:
          - arrangement: monolith
            database: Postgres

+          - arrangement: workers
+            database: Postgres
+
    steps:
-      # The path is set via a file given by $GITHUB_PATH. We need both Go 1.17 and GOPATH on the path to run Complement.
-      # See https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#adding-a-system-path
-      - name: "Set Go Version"
-        run: |
-          # Add Go 1.17 to the PATH: see https://github.com/actions/virtual-environments/blob/main/images/linux/Ubuntu2004-Readme.md#environment-variables-2
-          echo "$GOROOT_1_17_X64/bin" >> $GITHUB_PATH
-          # Add the Go path to the PATH: We need this so we can call gotestfmt
-          echo "~/go/bin" >> $GITHUB_PATH
-
-      - name: "Install Complement Dependencies"
-        run: |
-          sudo apt-get update && sudo apt-get install -y libolm3 libolm-dev
-          go get -v github.com/haveyoudebuggedit/gotestfmt/v2/cmd/gotestfmt@latest
-
      - name: Run actions/checkout@v2 for synapse
        uses: actions/checkout@v2
        with:
          path: synapse

-      - name: "Install custom gotestfmt template"
-        run: |
-          mkdir .gotestfmt/github -p
-          cp synapse/.ci/complement_package.gotpl .gotestfmt/github/package.gotpl
-
-      # Attempt to check out the same branch of Complement as the PR. If it
-      # doesn't exist, fallback to HEAD.
-      - name: Checkout complement
-        run: synapse/.ci/scripts/checkout_complement.sh
+      - name: Prepare Complement's Prerequisites
+        run: synapse/.ci/scripts/setup_complement_prerequisites.sh

      - run: |
          set -o pipefail
-          POSTGRES=${{ (matrix.database == 'Postgres') && 1 || '' }} COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | gotestfmt
-        shell: bash
-        name: Run Complement Tests
-
-  # We only run the workers tests on `develop` for now, because they're too slow to wait for on PRs.
-  # Sadly, you can't have an `if` condition on the value of a matrix, so this is a temporary, separate job for now.
-  # GitHub Actions doesn't support YAML anchors, so it's full-on duplication for now.
-  complement-developonly:
-    if: "${{ !failure() && !cancelled() && (github.ref == 'refs/heads/develop') }}"
-    needs: linting-done
-    runs-on: ubuntu-latest
-    
-    name: "Complement Workers (develop only)"
-
-    steps:
-      # The path is set via a file given by $GITHUB_PATH. We need both Go 1.17 and GOPATH on the path to run Complement.
-      # See https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#adding-a-system-path
-      - name: "Set Go Version"
-        run: |
-          # Add Go 1.17 to the PATH: see https://github.com/actions/virtual-environments/blob/main/images/linux/Ubuntu2004-Readme.md#environment-variables-2
-          echo "$GOROOT_1_17_X64/bin" >> $GITHUB_PATH
-          # Add the Go path to the PATH: We need this so we can call gotestfmt
-          echo "~/go/bin" >> $GITHUB_PATH
-
-      - name: "Install Complement Dependencies"
-        run: |
-          sudo apt-get -qq update && sudo apt-get install -qqy libolm3 libolm-dev
-          go get -v github.com/haveyoudebuggedit/gotestfmt/v2/cmd/gotestfmt@latest
-
-      - name: Run actions/checkout@v2 for synapse
-        uses: actions/checkout@v2
-        with:
-          path: synapse
-
-      - name: "Install custom gotestfmt template"
-        run: |
-          mkdir .gotestfmt/github -p
-          cp synapse/.ci/complement_package.gotpl .gotestfmt/github/package.gotpl
-
-      # Attempt to check out the same branch of Complement as the PR. If it
-      # doesn't exist, fallback to HEAD.
-      - name: Checkout complement
-        run: synapse/.ci/scripts/checkout_complement.sh
-
-      - run: |
-          set -o pipefail
-          WORKERS=1 COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | gotestfmt
+          POSTGRES=${{ (matrix.database == 'Postgres') && 1 || '' }} WORKERS=${{ (matrix.arrangement == 'workers') && 1 || '' }} COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | gotestfmt
        shell: bash
        name: Run Complement Tests

--- a/.github/workflows/twisted_trunk.yml
+++ b/.github/workflows/twisted_trunk.yml
@ -96,6 +96,51 @@ jobs:
            /logs/results.tap
            /logs/**/*.log*

+  complement:
+    if: "${{ !failure() && !cancelled() }}"
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - arrangement: monolith
+            database: SQLite
+
+          - arrangement: monolith
+            database: Postgres
+
+          - arrangement: workers
+            database: Postgres
+
+    steps:
+      - name: Run actions/checkout@v2 for synapse
+        uses: actions/checkout@v2
+        with:
+          path: synapse
+
+      - name: Prepare Complement's Prerequisites
+        run: synapse/.ci/scripts/setup_complement_prerequisites.sh
+
+      # This step is specific to the 'Twisted trunk' test run:
+      - name: Patch dependencies
+        run: |
+          set -x
+          DEBIAN_FRONTEND=noninteractive sudo apt-get install -yqq python3 pipx
+          pipx install poetry==1.1.12
+
+          poetry remove -n twisted
+          poetry add -n --extras tls git+https://github.com/twisted/twisted.git#trunk
+          poetry lock --no-update
+          # NOT IN 1.1.12 poetry lock --check
+        working-directory: synapse
+
+      - run: |
+          set -o pipefail
+          TEST_ONLY_SKIP_DEP_HASH_VERIFICATION=1 POSTGRES=${{ (matrix.database == 'Postgres') && 1 || '' }} WORKERS=${{ (matrix.arrangement == 'workers') && 1 || '' }} COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | gotestfmt
+        shell: bash
+        name: Run Complement Tests
+
  # open an issue if the build fails, so we know about it.
  open-issue:
    if: failure()
@ -103,6 +148,7 @@ jobs:
      - mypy
      - trial
      - sytest
+      - complement

    runs-on: ubuntu-latest

--- a/CHANGES.md
+++ b/CHANGES.md
@ -1,3 +1,83 @@
+Synapse 1.63.0rc1 (2022-07-12)
+==============================
+
+Features
+--------
+
+- Implement [MSC3827](https://github.com/matrix-org/matrix-spec-proposals/pull/3827): Filtering of /publicRooms by room type. ([\#13031](https://github.com/matrix-org/synapse/issues/13031))
+- Add a rate limit for local users sending invites. ([\#13125](https://github.com/matrix-org/synapse/issues/13125))
+- Improve validation logic in Synapse's REST endpoints. ([\#13148](https://github.com/matrix-org/synapse/issues/13148))
+
+
+Bugfixes
+--------
+
+- Fix application service not being able to join remote federated room without a profile set. ([\#13131](https://github.com/matrix-org/synapse/issues/13131))
+- Make use of the more robust `get_current_state` in `_get_state_map_for_room` to avoid breakages. ([\#13174](https://github.com/matrix-org/synapse/issues/13174))
+- Fix bug where rows were not deleted from `event_push_actions` table on large servers. Introduced in v1.62.0. ([\#13194](https://github.com/matrix-org/synapse/issues/13194))
+- Fix exception when using experimental [MSC3030](https://github.com/matrix-org/matrix-spec-proposals/pull/3030) `/timestamp_to_event` endpoint to look for remote federated imported events before room creation. ([\#13197](https://github.com/matrix-org/synapse/issues/13197))
+- Fix bug where notification counts would get stuck after a highlighted message. Broke in v1.62.0. ([\#13223](https://github.com/matrix-org/synapse/issues/13223))
+- Fix a long-standing bug where the `synapse_port_db` script could fail to copy rows with negative row ids. ([\#13226](https://github.com/matrix-org/synapse/issues/13226))
+- Fix MSC3202-enabled appservices not receiving to-device messages, preventing messages from being decrypted. ([\#13235](https://github.com/matrix-org/synapse/issues/13235))
+- Fix appservices not receiving room-less EDUs, like presence, if enabled. ([\#13236](https://github.com/matrix-org/synapse/issues/13236))
+
+
+Updates to the Docker image
+---------------------------
+
+- Bump the version of `lxml` in matrix.org Docker images Debian packages from 4.8.0 to 4.9.1. ([\#13207](https://github.com/matrix-org/synapse/issues/13207))
+
+
+Improved Documentation
+----------------------
+
+- Add an explanation of the `--report-stats` argument to the docs. ([\#13029](https://github.com/matrix-org/synapse/issues/13029))
+- Add a helpful example bash script to the contrib directory for creating multiple worker configuration files of the same type. Contributed by @villepeh. ([\#13032](https://github.com/matrix-org/synapse/issues/13032))
+- Clean up references to sample configuration and redirect users to the configuration manual instead. ([\#13077](https://github.com/matrix-org/synapse/issues/13077))
+- Add documentation for anonymised homeserver statistics collection. ([\#13086](https://github.com/matrix-org/synapse/issues/13086))
+- Fix wrong section header for `allow_public_rooms_over_federation` in the homeserver config documentation. ([\#13116](https://github.com/matrix-org/synapse/issues/13116))
+- Document how the Synapse team does reviews. ([\#13132](https://github.com/matrix-org/synapse/issues/13132))
+- Add a link to the configuration manual from the homeserver sample config documentation. ([\#13139](https://github.com/matrix-org/synapse/issues/13139))
+- Add missing links to config options. ([\#13166](https://github.com/matrix-org/synapse/issues/13166))
+- Add documentation for the existing `databases` option in the homeserver configuration manual. ([\#13212](https://github.com/matrix-org/synapse/issues/13212))
+
+
+Deprecations and Removals
+-------------------------
+
+- Remove obsolete and for 8 years unused `RoomEventsStoreTestCase`. Contributed by @arkamar. ([\#13200](https://github.com/matrix-org/synapse/issues/13200))
+
+
+Internal Changes
+----------------
+
+- Add type annotations to `tests.utils`. ([\#13028](https://github.com/matrix-org/synapse/issues/13028))
+- Support temporary experimental return values for spam checker module callbacks. ([\#13044](https://github.com/matrix-org/synapse/issues/13044))
+- Reduce memory consumption when processing incoming events in large rooms. ([\#13078](https://github.com/matrix-org/synapse/issues/13078), [\#13222](https://github.com/matrix-org/synapse/issues/13222))
+- Enable Complement testing in the 'Twisted Trunk' CI runs. ([\#13079](https://github.com/matrix-org/synapse/issues/13079), [\#13157](https://github.com/matrix-org/synapse/issues/13157))
+- Faster room joins: Handle race between persisting an event and un-partial stating a room. ([\#13100](https://github.com/matrix-org/synapse/issues/13100))
+- Add missing type hints to `synapse.logging`. ([\#13103](https://github.com/matrix-org/synapse/issues/13103))
+- Raise a `DependencyError` on missing dependencies instead of a `ConfigError`. ([\#13113](https://github.com/matrix-org/synapse/issues/13113))
+- Reduce DB usage of `/sync` when a large number of unread messages have recently been sent in a room. ([\#13119](https://github.com/matrix-org/synapse/issues/13119), [\#13153](https://github.com/matrix-org/synapse/issues/13153))
+- Improve startup times in Complement test runs against workers, particularly in CPU-constrained environments. ([\#13127](https://github.com/matrix-org/synapse/issues/13127))
+- Only one-line SQL statements for logging and tracing. ([\#13129](https://github.com/matrix-org/synapse/issues/13129))
+- Apply ratelimiting earlier in processing of /send request. ([\#13134](https://github.com/matrix-org/synapse/issues/13134))
+- Enforce type annotations for `tests.test_server`. ([\#13135](https://github.com/matrix-org/synapse/issues/13135))
+- Add type annotations to `tests.server`. ([\#13136](https://github.com/matrix-org/synapse/issues/13136))
+- Add support to `complement.sh` for skipping the docker build. ([\#13143](https://github.com/matrix-org/synapse/issues/13143), [\#13158](https://github.com/matrix-org/synapse/issues/13158))
+- Faster joins: skip waiting for full state when processing incoming events over federation. ([\#13144](https://github.com/matrix-org/synapse/issues/13144))
+- Improve exception handling when processing events received over federation. ([\#13145](https://github.com/matrix-org/synapse/issues/13145))
+- Faster room joins: fix race in recalculation of current room state. ([\#13151](https://github.com/matrix-org/synapse/issues/13151))
+- Add the ability to set the log level using the `SYNAPSE_TEST_LOG_LEVEL` environment when using `complement.sh`. ([\#13152](https://github.com/matrix-org/synapse/issues/13152))
+- Improve and fix type hints. ([\#13159](https://github.com/matrix-org/synapse/issues/13159))
+- Update config used by Complement to allow device name lookup over federation. ([\#13167](https://github.com/matrix-org/synapse/issues/13167))
+- Check that `auto_vacuum` is disabled when porting a SQLite database to Postgres, as `VACUUM`s must not be performed between runs of the script. ([\#13195](https://github.com/matrix-org/synapse/issues/13195))
+- Reduce number of queries used to get profile information. Contributed by Nick @ Beeper (@fizzadar). ([\#13209](https://github.com/matrix-org/synapse/issues/13209))
+- Reduce number of events queried during room creation. Contributed by Nick @ Beeper (@fizzadar). ([\#13210](https://github.com/matrix-org/synapse/issues/13210))
+- More aggressively rotate push actions. ([\#13211](https://github.com/matrix-org/synapse/issues/13211))
+- Add `max_line_length` setting for Python files to the `.editorconfig`. Contributed by @sumnerevans @ Beeper. ([\#13228](https://github.com/matrix-org/synapse/issues/13228))
+
+
 Synapse 1.62.0 (2022-07-05)
 ===========================

--- a/contrib/workers-bash-scripts/create-multiple-workers.md
+++ b/contrib/workers-bash-scripts/create-multiple-workers.md
@ -0,0 +1,31 @@
+# Creating multiple workers with a bash script
+
+Setting up multiple worker configuration files manually can be time-consuming.
+You can alternatively create multiple worker configuration files with a simple `bash` script. For example:
+
+```sh
+#!/bin/bash
+for i in {1..5}
+do
+cat << EOF >> generic_worker$i.yaml
+worker_app: synapse.app.generic_worker
+worker_name: generic_worker$i
+
+# The replication listener on the main synapse process.
+worker_replication_host: 127.0.0.1
+worker_replication_http_port: 9093
+
+worker_listeners:
+  - type: http
+    port: 808$i
+    resources:
+      - names: [client, federation]
+
+worker_log_config: /etc/matrix-synapse/generic-worker-log.yaml
+EOF
+done
+```
+
+This would create five generic workers with a unique `worker_name` field in each file and listening on ports 8081-8085.
+
+Customise the script to your needs.
--- a/debian/changelog
+++ b/debian/changelog
@ -1,3 +1,9 @@
+matrix-synapse-py3 (1.63.0~rc1) stable; urgency=medium
+
+  * New Synapse release 1.63.0rc1.
+
+ -- Synapse Packaging team <packages@matrix.org>  Tue, 12 Jul 2022 11:26:02 +0100
+
 matrix-synapse-py3 (1.62.0) stable; urgency=medium

  * New Synapse release 1.62.0.
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@ -62,7 +62,13 @@ WORKDIR /synapse
 # Copy just what we need to run `poetry export`...
 COPY pyproject.toml poetry.lock /synapse/

-RUN /root/.local/bin/poetry export --extras all -o /synapse/requirements.txt
+
+# If specified, we won't verify the hashes of dependencies.
+# This is only needed if the hashes of dependencies cannot be checked for some
+# reason, such as when a git repository is used directly as a dependency.
+ARG TEST_ONLY_SKIP_DEP_HASH_VERIFICATION
+
+RUN /root/.local/bin/poetry export --extras all -o /synapse/requirements.txt ${TEST_ONLY_SKIP_DEP_HASH_VERIFICATION:+--without-hashes}

 ###
 ### Stage 1: builder
@ -85,6 +91,7 @@ RUN \
    openssl \
    rustc \
    zlib1g-dev \
+    git \
    && rm -rf /var/lib/apt/lists/*

 # To speed up rebuilds, install all of the dependencies before we copy over
--- a/docker/README.md
+++ b/docker/README.md
@ -67,6 +67,13 @@ The following environment variables are supported in `generate` mode:
 * `UID`, `GID`: the user id and group id to use for creating the data
  directories. If unset, and no user is set via `docker run --user`, defaults
  to `991`, `991`.
+* `SYNAPSE_LOG_LEVEL`: the log level to use (one of `DEBUG`, `INFO`, `WARNING` or `ERROR`).
+  Defaults to `INFO`.
+* `SYNAPSE_LOG_SENSITIVE`: if set and the log level is set to `DEBUG`, Synapse
+  will log sensitive information such as access tokens.
+  This should not be needed unless you are a developer attempting to debug something
+  particularly tricky.
+

 ## Postgres

--- a/docker/complement/conf/start_for_complement.sh
+++ b/docker/complement/conf/start_for_complement.sh
@ -59,6 +59,9 @@ if [[ -n "$SYNAPSE_COMPLEMENT_USE_WORKERS" ]]; then
      synchrotron, \
      appservice, \
      pusher"
+
+  # Improve startup times by using a launcher based on fork()
+  export SYNAPSE_USE_EXPERIMENTAL_FORKING_LAUNCHER=1
 else
  # Empty string here means 'main process only'
  export SYNAPSE_WORKER_TYPES=""
--- a/docker/complement/conf/workers-shared-extra.yaml.j2
+++ b/docker/complement/conf/workers-shared-extra.yaml.j2
@ -81,6 +81,8 @@ rc_invites:

 federation_rr_transactions_per_room_per_second: 9999

+allow_device_name_lookup_over_federation: true
+
 ## Experimental Features ##

 experimental_features:
--- a/docker/conf-workers/synapse.supervisord.conf.j2
+++ b/docker/conf-workers/synapse.supervisord.conf.j2
@ -1,3 +1,24 @@
+{% if use_forking_launcher %}
+[program:synapse_fork]
+command=/usr/local/bin/python -m synapse.app.complement_fork_starter
+  {{ main_config_path }}
+  synapse.app.homeserver
+  --config-path="{{ main_config_path }}"
+  --config-path=/conf/workers/shared.yaml
+  {%- for worker in workers %}
+    -- {{ worker.app }}
+    --config-path="{{ main_config_path }}"
+    --config-path=/conf/workers/shared.yaml
+    --config-path=/conf/workers/{{ worker.name }}.yaml
+  {%- endfor %}
+stdout_logfile=/dev/stdout
+stdout_logfile_maxbytes=0
+stderr_logfile=/dev/stderr
+stderr_logfile_maxbytes=0
+autorestart=unexpected
+exitcodes=0
+
+{% else %}
 [program:synapse_main]
 command=/usr/local/bin/prefix-log /usr/local/bin/python -m synapse.app.homeserver
  --config-path="{{ main_config_path }}"
@ -13,7 +34,7 @@ autorestart=unexpected
 exitcodes=0


-{% for worker in workers %}
+  {% for worker in workers %}
 [program:synapse_{{ worker.name }}]
 command=/usr/local/bin/prefix-log /usr/local/bin/python -m {{ worker.app }}
  --config-path="{{ main_config_path }}"
@ -27,4 +48,5 @@ stdout_logfile_maxbytes=0
 stderr_logfile=/dev/stderr
 stderr_logfile_maxbytes=0

-{% endfor %}
+  {% endfor %}
+{% endif %}
--- a/docker/conf/log.config
+++ b/docker/conf/log.config
@ -2,7 +2,11 @@ version: 1

 formatters:
  precise:
+    {% if include_worker_name_in_log_line %}
+    format: '{{ worker_name }} | %(asctime)s - %(name)s - %(lineno)d - %(levelname)s - %(request)s - %(message)s'
+    {% else %}
    format: '%(asctime)s - %(name)s - %(lineno)d - %(levelname)s - %(request)s - %(message)s'
+    {% endif %}

 handlers:
 {% if LOG_FILE_PATH %}
@ -45,11 +49,17 @@ handlers:
    class: logging.StreamHandler
    formatter: precise

+{% if not SYNAPSE_LOG_SENSITIVE %}
+{#
+  If SYNAPSE_LOG_SENSITIVE is unset, then override synapse.storage.SQL to INFO
+  so that DEBUG entries (containing sensitive information) are not emitted.
+#}
 loggers:
    synapse.storage.SQL:
        # beware: increasing this to DEBUG will make synapse log sensitive
        # information such as access tokens.
        level: INFO
+{% endif %}

 root:
    level: {{ SYNAPSE_LOG_LEVEL or "INFO" }}
--- a/docker/configure_workers_and_start.py
+++ b/docker/configure_workers_and_start.py
@ -26,6 +26,13 @@
 #   * SYNAPSE_TLS_CERT: Path to a TLS certificate in PEM format.
 #   * SYNAPSE_TLS_KEY: Path to a TLS key. If this and SYNAPSE_TLS_CERT are specified,
 #         Nginx will be configured to serve TLS on port 8448.
+#   * SYNAPSE_USE_EXPERIMENTAL_FORKING_LAUNCHER: Whether to use the forking launcher,
+#         only intended for usage in Complement at the moment.
+#         No stability guarantees are provided.
+#   * SYNAPSE_LOG_LEVEL: Set this to DEBUG, INFO, WARNING or ERROR to change the
+#         log level. INFO is the default.
+#   * SYNAPSE_LOG_SENSITIVE: If unset, SQL and SQL values won't be logged,
+#         regardless of the SYNAPSE_LOG_LEVEL setting.
 #
 # NOTE: According to Complement's ENTRYPOINT expectations for a homeserver image (as defined
 # in the project's README), this script may be run multiple times, and functionality should
@ -35,7 +42,7 @@ import os
 import subprocess
 import sys
 from pathlib import Path
-from typing import Any, Dict, List, Mapping, MutableMapping, NoReturn, Set
+from typing import Any, Dict, List, Mapping, MutableMapping, NoReturn, Optional, Set

 import yaml
 from jinja2 import Environment, FileSystemLoader
@ -525,6 +532,7 @@ def generate_worker_files(
        "/etc/supervisor/conf.d/synapse.conf",
        workers=worker_descriptors,
        main_config_path=config_path,
+        use_forking_launcher=environ.get("SYNAPSE_USE_EXPERIMENTAL_FORKING_LAUNCHER"),
    )

    # healthcheck config
@ -548,18 +556,25 @@ def generate_worker_log_config(
    Returns: the path to the generated file
    """
    # Check whether we should write worker logs to disk, in addition to the console
-    extra_log_template_args = {}
+    extra_log_template_args: Dict[str, Optional[str]] = {}
    if environ.get("SYNAPSE_WORKERS_WRITE_LOGS_TO_DISK"):
-        extra_log_template_args["LOG_FILE_PATH"] = "{dir}/logs/{name}.log".format(
-            dir=data_dir, name=worker_name
-        )
+        extra_log_template_args["LOG_FILE_PATH"] = f"{data_dir}/logs/{worker_name}.log"
+
+    extra_log_template_args["SYNAPSE_LOG_LEVEL"] = environ.get("SYNAPSE_LOG_LEVEL")
+    extra_log_template_args["SYNAPSE_LOG_SENSITIVE"] = environ.get(
+        "SYNAPSE_LOG_SENSITIVE"
+    )
+
    # Render and write the file
-    log_config_filepath = "/conf/workers/{name}.log.config".format(name=worker_name)
+    log_config_filepath = f"/conf/workers/{worker_name}.log.config"
    convert(
        "/conf/log.config",
        log_config_filepath,
        worker_name=worker_name,
        **extra_log_template_args,
+        include_worker_name_in_log_line=environ.get(
+            "SYNAPSE_USE_EXPERIMENTAL_FORKING_LAUNCHER"
+        ),
    )
    return log_config_filepath

--- a/docker/start.py
+++ b/docker/start.py
@ -110,7 +110,11 @@ def generate_config_from_template(

    log_config_file = environ["SYNAPSE_LOG_CONFIG"]
    log("Generating log config file " + log_config_file)
-    convert("/conf/log.config", log_config_file, environ)
+    convert(
+        "/conf/log.config",
+        log_config_file,
+        {**environ, "include_worker_name_in_log_line": False},
+    )

    # Hopefully we already have a signing key, but generate one if not.
    args = [
--- a/docs/SUMMARY.md
+++ b/docs/SUMMARY.md
@ -69,6 +69,7 @@
      - [Federation](usage/administration/admin_api/federation.md)
    - [Manhole](manhole.md)
    - [Monitoring](metrics-howto.md)
+      - [Reporting Anonymised Statistics](usage/administration/monitoring/reporting_anonymised_statistics.md)
    - [Understanding Synapse Through Grafana Graphs](usage/administration/understanding_synapse_through_grafana_graphs.md)
    - [Useful SQL for Admins](usage/administration/useful_sql_for_admins.md)
    - [Database Maintenance Tools](usage/administration/database_maintenance_tools.md)
@ -80,6 +81,7 @@
 # Development
  - [Contributing Guide](development/contributing_guide.md)
  - [Code Style](code_style.md)
+  - [Reviewing Code](development/reviews.md)
  - [Release Cycle](development/releases.md)
  - [Git Usage](development/git.md)
  - [Testing]()
--- a/docs/admin_api/user_admin_api.md
+++ b/docs/admin_api/user_admin_api.md
@ -124,9 +124,8 @@ Body parameters:
  - `address` - string. Value of third-party ID.
  belonging to a user.
 - `external_ids` - array, optional. Allow setting the identifier of the external identity
-  provider for SSO (Single sign-on). Details in
-  [Sample Configuration File](../usage/configuration/homeserver_sample_config.html)
-  section `sso` and `oidc_providers`.
+  provider for SSO (Single sign-on). Details in the configuration manual under the
+  sections [sso](../usage/configuration/config_documentation.md#sso) and [oidc_providers](../usage/configuration/config_documentation.md#oidc_providers).
  - `auth_provider` - string. ID of the external identity provider. Value of `idp_id`
    in the homeserver configuration. Note that no error is raised if the provided
    value is not in the homeserver configuration.
--- a/docs/code_style.md
+++ b/docs/code_style.md
@ -70,82 +70,61 @@ on save as they take a while and can be very resource intensive.
    -   Avoid wildcard imports (`from synapse.types import *`) and
        relative imports (`from .types import UserID`).

-## Configuration file format
+## Configuration code and documentation format

-The [sample configuration file](./sample_config.yaml) acts as a
+When adding a configuration option to the code, if several settings are grouped into a single dict, ensure that your code
+correctly handles the top-level option being set to `None` (as it will be if no sub-options are enabled).
+
+The [configuration manual](usage/configuration/config_documentation.md) acts as a
 reference to Synapse's configuration options for server administrators.
 Remember that many readers will be unfamiliar with YAML and server
-administration in general, so that it is important that the file be as
-easy to understand as possible, which includes following a consistent
-format.
+administration in general, so it is important that when you add
+a configuration option the documentation be as easy to understand as possible, which 
+includes following a consistent format.

 Some guidelines follow:

-   Sections should be separated with a heading consisting of a single
-    line prefixed and suffixed with `##`. There should be **two** blank
-    lines before the section header, and **one** after.
-   Each option should be listed in the file with the following format:
-    -   A comment describing the setting. Each line of this comment
-        should be prefixed with a hash (`#`) and a space.
+- Each option should be listed in the config manual with the following format:
+      
+    - The name of the option, prefixed by `###`. 

-        The comment should describe the default behaviour (ie, what
+    - A comment which describes the default behaviour (i.e. what
        happens if the setting is omitted), as well as what the effect
        will be if the setting is changed.
-
-        Often, the comment end with something like "uncomment the
-        following to <do action>".
-
-    -   A line consisting of only `#`.
-    -   A commented-out example setting, prefixed with only `#`.
+    - An example setting, using backticks to define the code block

        For boolean (on/off) options, convention is that this example
-        should be the *opposite* to the default (so the comment will end
-        with "Uncomment the following to enable [or disable]
-        <feature>." For other options, the example should give some
-        non-default value which is likely to be useful to the reader.
+        should be the *opposite* to the default. For other options, the example should give
+        some non-default value which is likely to be useful to the reader.

-   There should be a blank line between each option.
-   Where several settings are grouped into a single dict, *avoid* the
-    convention where the whole block is commented out, resulting in
-    comment lines starting `# #`, as this is hard to read and confusing
-    to edit. Instead, leave the top-level config option uncommented, and
-    follow the conventions above for sub-options. Ensure that your code
-    correctly handles the top-level option being set to `None` (as it
-    will be if no sub-options are enabled).
-   Lines should be wrapped at 80 characters.
-   Use two-space indents.
-   `true` and `false` are spelt thus (as opposed to `True`, etc.)
-   Use single quotes (`'`) rather than double-quotes (`"`) or backticks
-    (`` ` ``) to refer to configuration options.
+- There should be a horizontal rule between each option, which can be achieved by adding `---` before and
+  after the option.
+- `true` and `false` are spelt thus (as opposed to `True`, etc.)

 Example:

+---
+### `modules`
+
+Use the `module` sub-option to add a module under `modules` to extend functionality. 
+The `module` setting then has a sub-option, `config`, which can be used to define some configuration
+for the `module`.
+
+Defaults to none.
+
+Example configuration:
 ```yaml
-## Frobnication ##
-
-# The frobnicator will ensure that all requests are fully frobnicated.
-# To enable it, uncomment the following.
-#
-#frobnicator_enabled: true
-
-# By default, the frobnicator will frobnicate with the default frobber.
-# The following will make it use an alternative frobber.
-#
-#frobincator_frobber: special_frobber
-
-# Settings for the frobber
-#
-frobber:
-  # frobbing speed. Defaults to 1.
-  #
-  #speed: 10
-
-  # frobbing distance. Defaults to 1000.
-  #
-  #distance: 100
+modules:
+  - module: my_super_module.MySuperClass
+    config:
+      do_thing: true
+  - module: my_other_super_module.SomeClass
+    config: {}
 ```
+---

 Note that the sample configuration is generated from the synapse code
 and is maintained by a script, `scripts-dev/generate_sample_config.sh`.
 Making sure that the output from this script matches the desired format
 is left as an exercise for the reader!
+
--- a/docs/development/contributing_guide.md
+++ b/docs/development/contributing_guide.md
@ -309,6 +309,10 @@ The above will run a monolithic (single-process) Synapse with SQLite as the data
 - Passing `POSTGRES=1` as an environment variable to use the Postgres database instead.
 - Passing `WORKERS=1` as an environment variable to use a workerised setup instead. This option implies the use of Postgres.

+To increase the log level for the tests, set `SYNAPSE_TEST_LOG_LEVEL`, e.g:
+```sh
+SYNAPSE_TEST_LOG_LEVEL=DEBUG COMPLEMENT_DIR=../complement ./scripts-dev/complement.sh -run TestImportHistoricalMessages
+```

 ### Prettier formatting with `gotestfmt`

@ -347,7 +351,7 @@ To prepare a Pull Request, please:
 3. `git push` your commit to your fork of Synapse;
 4. on GitHub, [create the Pull Request](https://docs.github.com/en/github/collaborating-with-issues-and-pull-requests/creating-a-pull-request);
 5. add a [changelog entry](#changelog) and push it to your Pull Request;
-6. for most contributors, that's all - however, if you are a member of the organization `matrix-org`, on GitHub, please request a review from `matrix.org / Synapse Core`.
+6. that's it for now, a non-draft pull request will automatically request review from the team;
 7. if you need to update your PR, please avoid rebasing and just add new commits to your branch.


@ -523,10 +527,13 @@ From this point, you should:
 1. Look at the results of the CI pipeline.
    - If there is any error, fix the error.
 2. If a developer has requested changes, make these changes and let us know if it is ready for a developer to review again.
+   - A pull request is a conversation, if you disagree with the suggestions, please respond and discuss it.
 3. Create a new commit with the changes.
    - Please do NOT overwrite the history. New commits make the reviewer's life easier.
    - Push this commits to your Pull Request.
 4. Back to 1.
+5. Once the pull request is ready for review again please re-request review from whichever developer did your initial
+  review (or leave a comment in the pull request that you believe all required changes have been done).

 Once both the CI and the developers are happy, the patch will be merged into Synapse and released shortly!

--- a/docs/development/reviews.md
+++ b/docs/development/reviews.md
@ -0,0 +1,41 @@
+Some notes on how we do reviews
+===============================
+
+The Synapse team works off a shared review queue -- any new pull requests for
+Synapse (or related projects) has a review requested from the entire team. Team
+members should process this queue using the following rules:
+
+* Any high urgency pull requests (e.g. fixes for broken continuous integration
+  or fixes for release blockers);
+* Follow-up reviews for pull requests which have previously received reviews;
+* Any remaining pull requests.
+
+For the latter two categories above, older pull requests should be prioritised.
+
+It is explicit that there is no priority given to pull requests from the team
+(vs from the community). If a pull request requires a quick turn around, please
+explicitly communicate this via [#synapse-dev:matrix.org](https://matrix.to/#/#synapse-dev:matrix.org)
+or as a comment on the pull request.
+
+Once an initial review has been completed and the author has made additional changes,
+follow-up reviews should go back to the same reviewer. This helps build a shared
+context and conversation between author and reviewer.
+
+As a team we aim to keep the number of inflight pull requests to a minimum to ensure
+that ongoing work is finished before starting new work.
+
+Performing a review
+-------------------
+
+To communicate to the rest of the team the status of each pull request, team
+members should do the following:
+
+* Assign themselves to the pull request (they should be left assigned to the
+  pull request until it is merged, closed, or are no longer the reviewer);
+* Review the pull request by leaving comments, questions, and suggestions;
+* Mark the pull request appropriately (as needing changes or accepted).
+
+If you are unsure about a particular part of the pull request (or are not confident
+in your understanding of part of the code) then ask questions or request review
+from the team again. When requesting review from the team be sure to leave a comment
+with the rationale on why you're putting it back in the queue.
--- a/docs/jwt.md
+++ b/docs/jwt.md
@ -49,9 +49,8 @@ as follows:
 * For other installation mechanisms, see the documentation provided by the
  maintainer.

-To enable the JSON web token integration, you should then add a `jwt_config` section
-to your configuration file (or uncomment the `enabled: true` line in the
-existing section). See [sample_config.yaml](./sample_config.yaml) for some
+To enable the JSON web token integration, you should then add a `jwt_config` option
+to your configuration file. See the [configuration manual](usage/configuration/config_documentation.md#jwt_config) for some
 sample settings.

 ## How to test JWT as a developer
--- a/docs/manhole.md
+++ b/docs/manhole.md
@ -13,8 +13,10 @@ environments where untrusted users have shell access.

 ## Configuring the manhole

-To enable it, first uncomment the `manhole` listener configuration in
-`homeserver.yaml`. The configuration is slightly different if you're using docker.
+To enable it, first add the `manhole` listener configuration in your
+`homeserver.yaml`. You can find information on how to do that 
+in the [configuration manual](usage/configuration/config_documentation.md#manhole_settings).
+The configuration is slightly different if you're using docker.

 #### Docker config

--- a/docs/message_retention_policies.md
+++ b/docs/message_retention_policies.md
@ -49,9 +49,9 @@ clients.

 ## Server configuration

-Support for this feature can be enabled and configured in the
-`retention` section of the Synapse configuration file (see the
-[sample file](https://github.com/matrix-org/synapse/blob/v1.36.0/docs/sample_config.yaml#L451-L518)).
+Support for this feature can be enabled and configured by adding a the
+`retention` in the Synapse configuration file (see
+[configuration manual](usage/configuration/config_documentation.md#retention)).

 To enable support for message retention policies, set the setting
 `enabled` in this section to `true`.
@ -65,8 +65,8 @@ message retention policy configured in its state. This allows server
 admins to ensure that messages are never kept indefinitely in a server's
 database. 

-A default policy can be defined as such, in the `retention` section of
-the configuration file:
+A default policy can be defined as such, by adding the `retention` option in
+the configuration file and adding these sub-options:

 ```yaml
 default_policy:
@ -86,8 +86,8 @@ Purge jobs are the jobs that Synapse runs in the background to purge
 expired events from the database. They are only run if support for
 message retention policies is enabled in the server's configuration. If
 no configuration for purge jobs is configured by the server admin,
-Synapse will use a default configuration, which is described in the
-[sample configuration file](https://github.com/matrix-org/synapse/blob/v1.36.0/docs/sample_config.yaml#L451-L518).
+Synapse will use a default configuration, which is described here in the
+[configuration manual](usage/configuration/config_documentation.md#retention).

 Some server admins might want a finer control on when events are removed
 depending on an event's room's policy. This can be done by setting the
@ -137,8 +137,8 @@ the server's database.
 ### Lifetime limits

 Server admins can set limits on the values of `max_lifetime` to use when
-purging old events in a room. These limits can be defined as such in the
-`retention` section of the configuration file:
+purging old events in a room. These limits can be defined under the
+`retention` option in the configuration file:

 ```yaml
 allowed_lifetime_min: 1d
--- a/docs/openid.md
+++ b/docs/openid.md
@ -45,8 +45,8 @@ as follows:
   maintainer.

 To enable the OpenID integration, you should then add a section to the `oidc_providers`
-setting in your configuration file (or uncomment one of the existing examples).
-See [sample_config.yaml](./sample_config.yaml) for some sample settings, as well as
+setting in your configuration file.
+See the [configuration manual](usage/configuration/config_documentation.md#oidc_providers) for some sample settings, as well as
 the text below for example configurations for specific providers.

 ## Sample configs
--- a/docs/postgres.md
+++ b/docs/postgres.md
@ -143,6 +143,14 @@ to do step 2.

 It is safe to at any time kill the port script and restart it.

+However, under no circumstances should the SQLite database be `VACUUM`ed between
+multiple runs of the script. Doing so can lead to an inconsistent copy of your database
+into Postgres.
+To avoid accidental error, the script will check that SQLite's `auto_vacuum` mechanism
+is disabled, but the script is not able to protect against a manual `VACUUM` operation
+performed either by the administrator or by any automated task that the administrator
+may have configured.
+
 Note that the database may take up significantly more (25% - 100% more)
 space on disk after porting to Postgres.

--- a/docs/setup/forward_proxy.md
+++ b/docs/setup/forward_proxy.md
@ -66,8 +66,8 @@ in Synapse can be deactivated.

 **NOTE**: This has an impact on security and is for testing purposes only!

-To deactivate the certificate validation, the following setting must be made in
-[homserver.yaml](../usage/configuration/homeserver_sample_config.md).
+To deactivate the certificate validation, the following setting must be added to
+your [homserver.yaml](../usage/configuration/homeserver_sample_config.md).

 ```yaml
 use_insecure_ssl_client_just_for_testing_do_not_use: true
--- a/docs/setup/installation.md
+++ b/docs/setup/installation.md
@ -232,7 +232,9 @@ python -m synapse.app.homeserver \
    --report-stats=[yes|no]
 ```

-... substituting an appropriate value for `--server-name`.
+... substituting an appropriate value for `--server-name` and choosing whether
+or not to report usage statistics (hostname, Synapse version, uptime, total
+users, etc.) to the developers via the `--report-stats` argument.

 This command will generate you a config file that you can then customise, but it will
 also generate a set of keys for you. These keys will allow your homeserver to
@ -405,11 +407,11 @@ The recommended way to do so is to set up a reverse proxy on port
 Alternatively, you can configure Synapse to expose an HTTPS port. To do
 so, you will need to edit `homeserver.yaml`, as follows:

- First, under the `listeners` section, uncomment the configuration for the
-  TLS-enabled listener. (Remove the hash sign (`#`) at the start of
-  each line). The relevant lines are like this:
+- First, under the `listeners` option, add the configuration for the
+  TLS-enabled listener like so:

 ```yaml
+listeners:
  - port: 8448
    type: http
    tls: true
@ -417,9 +419,11 @@ so, you will need to edit `homeserver.yaml`, as follows:
      - names: [client, federation]
  ```

- You will also need to uncomment the `tls_certificate_path` and
-  `tls_private_key_path` lines under the `TLS` section. You will need to manage
-  provisioning of these certificates yourself.
+- You will also need to add the options `tls_certificate_path` and
+  `tls_private_key_path`. to your configuration file. You will need to manage provisioning of 
+   these certificates yourself.
+- You can find more information about these options as well as how to configure synapse in the 
+  [configuration manual](../usage/configuration/config_documentation.md).

  If you are using your own certificate, be sure to use a `.pem` file that
  includes the full certificate chain including any intermediate certificates
--- a/docs/usage/administration/monitoring/reporting_anonymised_statistics.md
+++ b/docs/usage/administration/monitoring/reporting_anonymised_statistics.md
@ -0,0 +1,81 @@
+# Reporting Anonymised Statistics
+
+When generating your Synapse configuration file, you are asked whether you
+would like to report anonymised statistics to Matrix.org. These statistics
+provide the foundation a glimpse into the number of Synapse homeservers
+participating in the network, as well as statistics such as the number of
+rooms being created and messages being sent. This feature is sometimes
+affectionately called "phone-home" stats. Reporting
+[is optional](../../configuration/config_documentation.md#report_stats)
+and the reporting endpoint
+[can be configured](../../configuration/config_documentation.md#report_stats_endpoint),
+in case you would like to instead report statistics from a set of homeservers
+to your own infrastructure.
+
+This documentation aims to define the statistics available and the
+homeserver configuration options that exist to tweak it.
+
+## Available Statistics
+
+The following statistics are sent to the configured reporting endpoint:
+
+| Statistic Name             | Type   | Description                                                                                                                                                                                                                                                                                     |
+|----------------------------|--------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| `memory_rss`               | int    | The memory usage of the process (in kilobytes on Unix-based systems, bytes on MacOS).                                                                                                                                                                                                           |
+| `cpu_average`              | int    | CPU time in % of a single core (not % of all cores).                                                                                                                                                                                                                                            |              
+| `homeserver`               | string | The homeserver's server name.                                                                                                                                                                                                                                                                   |
+| `server_context`           | string | An arbitrary string used to group statistics from a set of homeservers.                                                                                                                                                                                                                         |
+| `timestamp`                | int    | The current time, represented as the number of seconds since the epoch.                                                                                                                                                                                                                         |                 
+| `uptime_seconds`           | int    | The number of seconds since the homeserver was last started.                                                                                                                                                                                                                                    |
+| `python_version`           | string | The Python version number in use (e.g "3.7.1"). Taken from `sys.version_info`.                                                                                                                                                                                                                  |
+| `total_users`              | int    | The number of registered users on the homeserver.                                                                                                                                                                                                                                               |
+| `total_nonbridged_users`   | int    | The number of users, excluding those created by an Application Service.                                                                                                                                                                                                                         |
+| `daily_user_type_native`   | int    | The number of native users created in the last 24 hours.                                                                                                                                                                                                                                        |
+| `daily_user_type_guest`    | int    | The number of guest users created in the last 24 hours.                                                                                                                                                                                                                                         |
+| `daily_user_type_bridged`  | int    | The number of users created by Application Services in the last 24 hours.                                                                                                                                                                                                                       |
+| `total_room_count`         | int    | The total number of rooms present on the homeserver.                                                                                                                                                                                                                                            |
+| `daily_active_users`       | int    | The number of unique users[^1] that have used the homeserver in the last 24 hours.                                                                                                                                                                                                              |
+| `monthly_active_users`     | int    | The number of unique users[^1] that have used the homeserver in the last 30 days.                                                                                                                                                                                                               |
+| `daily_active_rooms`       | int    | The number of rooms that have had a (state) event with the type `m.room.message` sent in them in the last 24 hours.                                                                                                                                                                             |
+| `daily_active_e2ee_rooms`  | int    | The number of rooms that have had a (state) event with the type `m.room.encrypted` sent in them in the last 24 hours.                                                                                                                                                                           |
+| `daily_messages`           | int    | The number of (state) events with the type `m.room.message` seen in the last 24 hours.                                                                                                                                                                                                          |
+| `daily_e2ee_messages`      | int    | The number of (state) events with the type `m.room.encrypted` seen in the last 24 hours.                                                                                                                                                                                                        |
+| `daily_sent_messages`      | int    | The number of (state) events sent by a local user with the type `m.room.message` seen in the last 24 hours.                                                                                                                                                                                     |
+| `daily_sent_e2ee_messages` | int    | The number of (state) events sent by a local user with the type `m.room.encrypted` seen in the last 24 hours.                                                                                                                                                                                   |
+| `r30_users_all`            | int    | The number of 30 day retained users, defined as users who have created their accounts more than 30 days ago, where they were last seen at most 30 days ago and where those two timestamps are over 30 days apart. Includes clients that do not fit into the below r30 client types.             |
+| `r30_users_android`        | int    | The number of 30 day retained users, as defined above. Filtered only to clients with "Android" in the user agent string.                                                                                                                                                                        |
+| `r30_users_ios`            | int    | The number of 30 day retained users, as defined above. Filtered only to clients with "iOS" in the user agent string.                                                                                                                                                                            |
+| `r30_users_electron`       | int    | The number of 30 day retained users, as defined above. Filtered only to clients with "Electron" in the user agent string.                                                                                                                                                                       |
+| `r30_users_web`            | int    | The number of 30 day retained users, as defined above. Filtered only to clients with "Mozilla" or "Gecko" in the user agent string.                                                                                                                                                             |
+| `r30v2_users_all`          | int    | The number of 30 day retained users, with a revised algorithm. Defined as users that appear more than once in the past 60 days, and have more than 30 days between the most and least recent appearances in the past 60 days. Includes clients that do not fit into the below r30 client types. |
+| `r30v2_users_android`      | int    | The number of 30 day retained users, as defined above. Filtered only to clients with ("riot" or "element") and "android" (case-insensitive) in the user agent string.                                                                                                                           |
+| `r30v2_users_ios`          | int    | The number of 30 day retained users, as defined above. Filtered only to clients with ("riot" or "element") and "ios" (case-insensitive) in the user agent string.                                                                                                                               |
+| `r30v2_users_electron`     | int    | The number of 30 day retained users, as defined above. Filtered only to clients with ("riot" or "element") and "electron" (case-insensitive) in the user agent string.                                                                                                                          |
+| `r30v2_users_web`          | int    | The number of 30 day retained users, as defined above. Filtered only to clients with "mozilla" or "gecko" (case-insensitive) in the user agent string.                                                                                                                                          |
+| `cache_factor`             | int    | The configured [`global factor`](../../configuration/config_documentation.md#caching) value for caching.                                                                                                                                                                                        |
+| `event_cache_size`         | int    | The configured [`event_cache_size`](../../configuration/config_documentation.md#caching) value for caching.                                                                                                                                                                                     |
+| `database_engine`          | string | The database engine that is in use. Either "psycopg2" meaning PostgreSQL is in use, or "sqlite3" for SQLite3.                                                                                                                                                                                   |
+| `database_server_version` | string | The version of the database server. Examples being "10.10" for PostgreSQL server version 10.0, and "3.38.5" for SQLite 3.38.5 installed on the system.                                                                                                                                          |
+| `log_level` | string | The log level in use. Examples are "INFO", "WARNING", "ERROR", "DEBUG", etc.                                                                                                                                                                                                                    |
+
+
+[^1]: Native matrix users and guests are always counted. If the
+[`track_puppeted_user_ips`](../../configuration/config_documentation.md#track_puppeted_user_ips)
+option is set to `true`, "puppeted" users (users that an Application Service have performed
+[an action on behalf of](https://spec.matrix.org/v1.3/application-service-api/#identity-assertion))
+will also be counted. Note that an Application Service can "puppet" any user in their
+[user namespace](https://spec.matrix.org/v1.3/application-service-api/#registration),
+not only users that the Application Service has created. If this happens, the Application Service
+will additionally be counted as a user (irrespective of `track_puppeted_user_ips`).
+
+## Using a Custom Statistics Collection Server
+
+If statistics reporting is enabled, the endpoint that Synapse sends metrics to is configured by the
+[`report_stats_endpoint`](../../configuration/config_documentation.md#report_stats_endpoint) config
+option. By default, statistics are sent to Matrix.org.
+
+If you would like to set up your own statistics collection server and send metrics there, you may
+consider using one of the following known implementations:
+
+* [Matrix.org's Panopticon](https://github.com/matrix-org/panopticon)
+* [Famedly's Barad-dûr](https://gitlab.com/famedly/company/devops/services/barad-dur)
--- a/docs/usage/configuration/config_documentation.md
+++ b/docs/usage/configuration/config_documentation.md
@ -317,7 +317,7 @@ Example configuration:
 allow_public_rooms_without_auth: true
 ```
 ---
-### `allow_public_rooms_without_auth`
+### `allow_public_rooms_over_federation`

 If set to true, allows any other homeserver to fetch the server's public
 rooms directory via federation. Defaults to false.
@ -591,7 +591,7 @@ Example configuration:
 dummy_events_threshold: 5
 ```
 ---
-Config option `delete_stale_devices_after`
+### `delete_stale_devices_after`

 An optional duration. If set, Synapse will run a daily background task to log out and
 delete any device that hasn't been accessed for more than the specified amount of time.
@ -1257,6 +1257,98 @@ database:
    cp_max: 10
 ```
 ---
+### `databases`
+
+The `databases` option allows specifying a mapping between certain database tables and
+database host details, spreading the load of a single Synapse instance across multiple
+database backends. This is often referred to as "database sharding". This option is only
+supported for PostgreSQL database backends.
+
+**Important note:** This is a supported option, but is not currently used in production by the
+Matrix.org Foundation. Proceed with caution and always make backups.
+
+`databases` is a dictionary of arbitrarily-named database entries. Each entry is equivalent
+to the value of the `database` homeserver config option (see above), with the addition of
+a `data_stores` key. `data_stores` is an array of strings that specifies the data store(s)
+(a defined label for a set of tables) that should be stored on the associated database
+backend entry.
+
+The currently defined values for `data_stores` are:
+
+* `"state"`: Database that relates to state groups will be stored in this database.
+
+  Specifically, that means the following tables:
+  * `state_groups`
+  * `state_group_edges`
+  * `state_groups_state`
+
+  And the following sequences:
+  * `state_groups_seq_id`
+
+* `"main"`: All other database tables and sequences.
+
+All databases will end up with additional tables used for tracking database schema migrations
+and any pending background updates. Synapse will create these automatically on startup when checking for
+and/or performing database schema migrations.
+
+To migrate an existing database configuration (e.g. all tables on a single database) to a different
+configuration (e.g. the "main" data store on one database, and "state" on another), do the following:
+
+1. Take a backup of your existing database. Things can and do go wrong and database corruption is no joke!
+2. Ensure all pending database migrations have been applied and background updates have run. The simplest
+   way to do this is to use the `update_synapse_database` script supplied with your Synapse installation.
+
+   ```sh
+   update_synapse_database --database-config homeserver.yaml --run-background-updates
+   ```
+
+3. Copy over the necessary tables and sequences from one database to the other. Tables relating to database
+   migrations, schemas, schema versions and background updates should **not** be copied.
+
+   As an example, say that you'd like to split out the "state" data store from an existing database which
+   currently contains all data stores.
+
+   Simply copy the tables and sequences defined above for the "state" datastore from the existing database
+   to the secondary database. As noted above, additional tables will be created in the secondary database
+   when Synapse is started.
+
+4. Modify/create the `databases` option in your `homeserver.yaml` to match the desired database configuration.
+5. Start Synapse. Check that it starts up successfully and that things generally seem to be working.
+6. Drop the old tables that were copied in step 3.
+
+Only one of the options `database` or `databases` may be specified in your config, but not both.
+
+Example configuration:
+
+```yaml
+databases:
+  basement_box:
+    name: psycopg2
+    txn_limit: 10000
+    data_stores: ["main"]
+    args:
+      user: synapse_user
+      password: secretpassword
+      database: synapse_main
+      host: localhost
+      port: 5432
+      cp_min: 5
+      cp_max: 10
+
+  my_other_database:
+    name: psycopg2
+    txn_limit: 10000
+    data_stores: ["state"]
+    args:
+      user: synapse_user
+      password: secretpassword
+      database: synapse_state
+      host: localhost
+      port: 5432
+      cp_min: 5
+      cp_max: 10
+```
+---
 ## Logging ##
 Config options related to logging. 

@ -1843,7 +1935,7 @@ Example configuration:
 turn_shared_secret: "YOUR_SHARED_SECRET"
 ```
 ----
-Config options: `turn_username` and `turn_password`
+### `turn_username` and `turn_password`

 The Username and password if the TURN server needs them and does not use a token.

@ -2999,7 +3091,7 @@ This setting has the following sub-options:
 * `localdb_enabled`: Set to false to disable authentication against the local password
   database. This is ignored if `enabled` is false, and is only useful
   if you have other `password_providers`. Defaults to true. 
-* `pepper`: Set the value here to a secret random string for extra security. # Uncomment and change to a secret random string for extra security.
+* `pepper`: Set the value here to a secret random string for extra security.
   DO NOT CHANGE THIS AFTER INITIAL SETUP!
 * `policy`: Define and enforce a password policy, such as minimum lengths for passwords, etc. 
   Each parameter is optional. This is an implementation of MSC2000. Parameters are as follows:
@ -3373,7 +3465,7 @@ alias_creation_rules:
    action: deny
 ```
 ---
-Config options: `room_list_publication_rules`
+### `room_list_publication_rules`

 The `room_list_publication_rules` option controls who can publish and
 which rooms can be published in the public room list.
--- a/docs/usage/configuration/homeserver_sample_config.md
+++ b/docs/usage/configuration/homeserver_sample_config.md
@ -9,6 +9,9 @@ a real homeserver.yaml. Instead, if you are starting from scratch, please genera
 a fresh config using Synapse by following the instructions in
 [Installation](../../setup/installation.md).

+Documentation for all configuration options can be found in the
+[Configuration Manual](./config_documentation.md).
+
 ```yaml
 {{#include ../../sample_config.yaml}}
 ```
--- a/docs/usage/configuration/user_authentication/single_sign_on/cas.md
+++ b/docs/usage/configuration/user_authentication/single_sign_on/cas.md
@ -4,5 +4,5 @@ Synapse supports authenticating users via the [Central Authentication
 Service protocol](https://en.wikipedia.org/wiki/Central_Authentication_Service)
 (CAS) natively.

-Please see the `cas_config` and `sso` sections of the [Synapse configuration
-file](../../../configuration/homeserver_sample_config.md) for more details.
+Please see the [cas_config](../../../configuration/config_documentation.md#cas_config) and [sso](../../../configuration/config_documentation.md#sso)
+sections of the configuration manual for more details.
--- a/mypy.ini
+++ b/mypy.ini
@ -56,7 +56,6 @@ exclude = (?x)
   |tests/server.py
   |tests/server_notices/test_resource_limits_server_notices.py
   |tests/test_metrics.py
-   |tests/test_server.py
   |tests/test_state.py
   |tests/test_terms_auth.py
   |tests/util/caches/test_cached_call.py
@ -74,7 +73,6 @@ exclude = (?x)
   |tests/util/test_lrucache.py
   |tests/util/test_rwlock.py
   |tests/util/test_wheel_timer.py
-   |tests/utils.py
   )$

 [mypy-synapse.federation.transport.client]
@ -89,9 +87,6 @@ disallow_untyped_defs = False
 [mypy-synapse.logging.opentracing]
 disallow_untyped_defs = False

-[mypy-synapse.logging.scopecontextmanager]
-disallow_untyped_defs = False
-
 [mypy-synapse.metrics._reactor_metrics]
 disallow_untyped_defs = False
 # This module imports select.epoll. That exists on Linux, but doesn't on macOS.
@ -131,6 +126,9 @@ disallow_untyped_defs = True
 [mypy-tests.federation.transport.test_client]
 disallow_untyped_defs = True

+[mypy-tests.utils]
+disallow_untyped_defs = True
+

 ;; Dependencies without annotations
 ;; Before ignoring a module, check to see if type stubs are available.
--- a/poetry.lock
+++ b/poetry.lock
@ -502,7 +502,7 @@ pyasn1 = ">=0.4.6"

 [[package]]
 name = "lxml"
-version = "4.8.0"
+version = "4.9.1"
 description = "Powerful and Pythonic XML processing library combining libxml2/libxslt with the ElementTree API."
 category = "main"
 optional = true
@ -1937,67 +1937,76 @@ ldap3 = [
    {file = "ldap3-2.9.1.tar.gz", hash = "sha256:f3e7fc4718e3f09dda568b57100095e0ce58633bcabbed8667ce3f8fbaa4229f"},
 ]
 lxml = [
-    {file = "lxml-4.8.0-cp27-cp27m-macosx_10_14_x86_64.whl", hash = "sha256:e1ab2fac607842ac36864e358c42feb0960ae62c34aa4caaf12ada0a1fb5d99b"},
-    {file = "lxml-4.8.0-cp27-cp27m-manylinux_2_5_i686.manylinux1_i686.whl", hash = "sha256:28d1af847786f68bec57961f31221125c29d6f52d9187c01cd34dc14e2b29430"},
-    {file = "lxml-4.8.0-cp27-cp27m-manylinux_2_5_x86_64.manylinux1_x86_64.whl", hash = "sha256:b92d40121dcbd74831b690a75533da703750f7041b4bf951befc657c37e5695a"},
-    {file = "lxml-4.8.0-cp27-cp27m-win32.whl", hash = "sha256:e01f9531ba5420838c801c21c1b0f45dbc9607cb22ea2cf132844453bec863a5"},
-    {file = "lxml-4.8.0-cp27-cp27m-win_amd64.whl", hash = "sha256:6259b511b0f2527e6d55ad87acc1c07b3cbffc3d5e050d7e7bcfa151b8202df9"},
-    {file = "lxml-4.8.0-cp27-cp27mu-manylinux_2_5_i686.manylinux1_i686.whl", hash = "sha256:1010042bfcac2b2dc6098260a2ed022968dbdfaf285fc65a3acf8e4eb1ffd1bc"},
-    {file = "lxml-4.8.0-cp27-cp27mu-manylinux_2_5_x86_64.manylinux1_x86_64.whl", hash = "sha256:fa56bb08b3dd8eac3a8c5b7d075c94e74f755fd9d8a04543ae8d37b1612dd170"},
-    {file = "lxml-4.8.0-cp310-cp310-macosx_10_15_x86_64.whl", hash = "sha256:31ba2cbc64516dcdd6c24418daa7abff989ddf3ba6d3ea6f6ce6f2ed6e754ec9"},
-    {file = "lxml-4.8.0-cp310-cp310-manylinux_2_12_i686.manylinux2010_i686.manylinux_2_24_i686.whl", hash = "sha256:31499847fc5f73ee17dbe1b8e24c6dafc4e8d5b48803d17d22988976b0171f03"},
-    {file = "lxml-4.8.0-cp310-cp310-manylinux_2_17_aarch64.manylinux2014_aarch64.manylinux_2_24_aarch64.whl", hash = "sha256:5f7d7d9afc7b293147e2d506a4596641d60181a35279ef3aa5778d0d9d9123fe"},
-    {file = "lxml-4.8.0-cp310-cp310-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_24_x86_64.whl", hash = "sha256:a3c5f1a719aa11866ffc530d54ad965063a8cbbecae6515acbd5f0fae8f48eaa"},
-    {file = "lxml-4.8.0-cp310-cp310-musllinux_1_1_x86_64.whl", hash = "sha256:6268e27873a3d191849204d00d03f65c0e343b3bcb518a6eaae05677c95621d1"},
-    {file = "lxml-4.8.0-cp310-cp310-win32.whl", hash = "sha256:330bff92c26d4aee79c5bc4d9967858bdbe73fdbdbacb5daf623a03a914fe05b"},
-    {file = "lxml-4.8.0-cp310-cp310-win_amd64.whl", hash = "sha256:b2582b238e1658c4061ebe1b4df53c435190d22457642377fd0cb30685cdfb76"},
-    {file = "lxml-4.8.0-cp35-cp35m-manylinux_2_5_i686.manylinux1_i686.whl", hash = "sha256:a2bfc7e2a0601b475477c954bf167dee6d0f55cb167e3f3e7cefad906e7759f6"},
-    {file = "lxml-4.8.0-cp35-cp35m-manylinux_2_5_x86_64.manylinux1_x86_64.whl", hash = "sha256:a1547ff4b8a833511eeaceacbcd17b043214fcdb385148f9c1bc5556ca9623e2"},
-    {file = "lxml-4.8.0-cp35-cp35m-win32.whl", hash = "sha256:a9f1c3489736ff8e1c7652e9dc39f80cff820f23624f23d9eab6e122ac99b150"},
-    {file = "lxml-4.8.0-cp35-cp35m-win_amd64.whl", hash = "sha256:530f278849031b0eb12f46cca0e5db01cfe5177ab13bd6878c6e739319bae654"},
-    {file = "lxml-4.8.0-cp36-cp36m-macosx_10_14_x86_64.whl", hash = "sha256:078306d19a33920004addeb5f4630781aaeabb6a8d01398045fcde085091a169"},
-    {file = "lxml-4.8.0-cp36-cp36m-manylinux_2_12_i686.manylinux2010_i686.manylinux_2_24_i686.whl", hash = "sha256:86545e351e879d0b72b620db6a3b96346921fa87b3d366d6c074e5a9a0b8dadb"},
-    {file = "lxml-4.8.0-cp36-cp36m-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:24f5c5ae618395ed871b3d8ebfcbb36e3f1091fd847bf54c4de623f9107942f3"},
-    {file = "lxml-4.8.0-cp36-cp36m-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_24_x86_64.whl", hash = "sha256:bbab6faf6568484707acc052f4dfc3802bdb0cafe079383fbaa23f1cdae9ecd4"},
-    {file = "lxml-4.8.0-cp36-cp36m-manylinux_2_5_i686.manylinux1_i686.whl", hash = "sha256:7993232bd4044392c47779a3c7e8889fea6883be46281d45a81451acfd704d7e"},
-    {file = "lxml-4.8.0-cp36-cp36m-manylinux_2_5_x86_64.manylinux1_x86_64.whl", hash = "sha256:6d6483b1229470e1d8835e52e0ff3c6973b9b97b24cd1c116dca90b57a2cc613"},
-    {file = "lxml-4.8.0-cp36-cp36m-musllinux_1_1_x86_64.whl", hash = "sha256:ad4332a532e2d5acb231a2e5d33f943750091ee435daffca3fec0a53224e7e33"},
-    {file = "lxml-4.8.0-cp36-cp36m-win32.whl", hash = "sha256:db3535733f59e5605a88a706824dfcb9bd06725e709ecb017e165fc1d6e7d429"},
-    {file = "lxml-4.8.0-cp36-cp36m-win_amd64.whl", hash = "sha256:5f148b0c6133fb928503cfcdfdba395010f997aa44bcf6474fcdd0c5398d9b63"},
-    {file = "lxml-4.8.0-cp37-cp37m-macosx_10_14_x86_64.whl", hash = "sha256:8a31f24e2a0b6317f33aafbb2f0895c0bce772980ae60c2c640d82caac49628a"},
-    {file = "lxml-4.8.0-cp37-cp37m-manylinux_2_12_i686.manylinux2010_i686.manylinux_2_24_i686.whl", hash = "sha256:719544565c2937c21a6f76d520e6e52b726d132815adb3447ccffbe9f44203c4"},
-    {file = "lxml-4.8.0-cp37-cp37m-manylinux_2_17_aarch64.manylinux2014_aarch64.manylinux_2_24_aarch64.whl", hash = "sha256:c0b88ed1ae66777a798dc54f627e32d3b81c8009967c63993c450ee4cbcbec15"},
-    {file = "lxml-4.8.0-cp37-cp37m-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_24_x86_64.whl", hash = "sha256:fa9b7c450be85bfc6cd39f6df8c5b8cbd76b5d6fc1f69efec80203f9894b885f"},
-    {file = "lxml-4.8.0-cp37-cp37m-manylinux_2_5_i686.manylinux1_i686.whl", hash = "sha256:e9f84ed9f4d50b74fbc77298ee5c870f67cb7e91dcdc1a6915cb1ff6a317476c"},
-    {file = "lxml-4.8.0-cp37-cp37m-manylinux_2_5_x86_64.manylinux1_x86_64.whl", hash = "sha256:1d650812b52d98679ed6c6b3b55cbb8fe5a5460a0aef29aeb08dc0b44577df85"},
-    {file = "lxml-4.8.0-cp37-cp37m-musllinux_1_1_x86_64.whl", hash = "sha256:80bbaddf2baab7e6de4bc47405e34948e694a9efe0861c61cdc23aa774fcb141"},
-    {file = "lxml-4.8.0-cp37-cp37m-win32.whl", hash = "sha256:6f7b82934c08e28a2d537d870293236b1000d94d0b4583825ab9649aef7ddf63"},
-    {file = "lxml-4.8.0-cp37-cp37m-win_amd64.whl", hash = "sha256:e1fd7d2fe11f1cb63d3336d147c852f6d07de0d0020d704c6031b46a30b02ca8"},
-    {file = "lxml-4.8.0-cp38-cp38-macosx_10_14_x86_64.whl", hash = "sha256:5045ee1ccd45a89c4daec1160217d363fcd23811e26734688007c26f28c9e9e7"},
-    {file = "lxml-4.8.0-cp38-cp38-manylinux_2_12_i686.manylinux2010_i686.manylinux_2_24_i686.whl", hash = "sha256:0c1978ff1fd81ed9dcbba4f91cf09faf1f8082c9d72eb122e92294716c605428"},
-    {file = "lxml-4.8.0-cp38-cp38-manylinux_2_17_aarch64.manylinux2014_aarch64.manylinux_2_24_aarch64.whl", hash = "sha256:52cbf2ff155b19dc4d4100f7442f6a697938bf4493f8d3b0c51d45568d5666b5"},
-    {file = "lxml-4.8.0-cp38-cp38-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_24_x86_64.whl", hash = "sha256:ce13d6291a5f47c1c8dbd375baa78551053bc6b5e5c0e9bb8e39c0a8359fd52f"},
-    {file = "lxml-4.8.0-cp38-cp38-manylinux_2_5_i686.manylinux1_i686.whl", hash = "sha256:e11527dc23d5ef44d76fef11213215c34f36af1608074561fcc561d983aeb870"},
-    {file = "lxml-4.8.0-cp38-cp38-manylinux_2_5_x86_64.manylinux1_x86_64.whl", hash = "sha256:60d2f60bd5a2a979df28ab309352cdcf8181bda0cca4529769a945f09aba06f9"},
-    {file = "lxml-4.8.0-cp38-cp38-musllinux_1_1_x86_64.whl", hash = "sha256:62f93eac69ec0f4be98d1b96f4d6b964855b8255c345c17ff12c20b93f247b68"},
-    {file = "lxml-4.8.0-cp38-cp38-win32.whl", hash = "sha256:20b8a746a026017acf07da39fdb10aa80ad9877046c9182442bf80c84a1c4696"},
-    {file = "lxml-4.8.0-cp38-cp38-win_amd64.whl", hash = "sha256:891dc8f522d7059ff0024cd3ae79fd224752676447f9c678f2a5c14b84d9a939"},
-    {file = "lxml-4.8.0-cp39-cp39-macosx_10_15_x86_64.whl", hash = "sha256:b6fc2e2fb6f532cf48b5fed57567ef286addcef38c28874458a41b7837a57807"},
-    {file = "lxml-4.8.0-cp39-cp39-manylinux_2_12_i686.manylinux2010_i686.manylinux_2_24_i686.whl", hash = "sha256:74eb65ec61e3c7c019d7169387d1b6ffcfea1b9ec5894d116a9a903636e4a0b1"},
-    {file = "lxml-4.8.0-cp39-cp39-manylinux_2_17_aarch64.manylinux2014_aarch64.manylinux_2_24_aarch64.whl", hash = "sha256:627e79894770783c129cc5e89b947e52aa26e8e0557c7e205368a809da4b7939"},
-    {file = "lxml-4.8.0-cp39-cp39-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_24_x86_64.whl", hash = "sha256:545bd39c9481f2e3f2727c78c169425efbfb3fbba6e7db4f46a80ebb249819ca"},
-    {file = "lxml-4.8.0-cp39-cp39-manylinux_2_5_i686.manylinux1_i686.whl", hash = "sha256:5a58d0b12f5053e270510bf12f753a76aaf3d74c453c00942ed7d2c804ca845c"},
-    {file = "lxml-4.8.0-cp39-cp39-manylinux_2_5_x86_64.manylinux1_x86_64.whl", hash = "sha256:ec4b4e75fc68da9dc0ed73dcdb431c25c57775383fec325d23a770a64e7ebc87"},
-    {file = "lxml-4.8.0-cp39-cp39-musllinux_1_1_x86_64.whl", hash = "sha256:5804e04feb4e61babf3911c2a974a5b86f66ee227cc5006230b00ac6d285b3a9"},
-    {file = "lxml-4.8.0-cp39-cp39-win32.whl", hash = "sha256:aa0cf4922da7a3c905d000b35065df6184c0dc1d866dd3b86fd961905bbad2ea"},
-    {file = "lxml-4.8.0-cp39-cp39-win_amd64.whl", hash = "sha256:dd10383f1d6b7edf247d0960a3db274c07e96cf3a3fc7c41c8448f93eac3fb1c"},
-    {file = "lxml-4.8.0-pp37-pypy37_pp73-macosx_10_14_x86_64.whl", hash = "sha256:2403a6d6fb61c285969b71f4a3527873fe93fd0abe0832d858a17fe68c8fa507"},
-    {file = "lxml-4.8.0-pp37-pypy37_pp73-manylinux_2_12_i686.manylinux2010_i686.manylinux_2_24_i686.whl", hash = "sha256:986b7a96228c9b4942ec420eff37556c5777bfba6758edcb95421e4a614b57f9"},
-    {file = "lxml-4.8.0-pp37-pypy37_pp73-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_24_x86_64.whl", hash = "sha256:6fe4ef4402df0250b75ba876c3795510d782def5c1e63890bde02d622570d39e"},
-    {file = "lxml-4.8.0-pp38-pypy38_pp73-macosx_10_14_x86_64.whl", hash = "sha256:f10ce66fcdeb3543df51d423ede7e238be98412232fca5daec3e54bcd16b8da0"},
-    {file = "lxml-4.8.0-pp38-pypy38_pp73-manylinux_2_12_i686.manylinux2010_i686.manylinux_2_24_i686.whl", hash = "sha256:730766072fd5dcb219dd2b95c4c49752a54f00157f322bc6d71f7d2a31fecd79"},
-    {file = "lxml-4.8.0-pp38-pypy38_pp73-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_24_x86_64.whl", hash = "sha256:8b99ec73073b37f9ebe8caf399001848fced9c08064effdbfc4da2b5a8d07b93"},
-    {file = "lxml-4.8.0.tar.gz", hash = "sha256:f63f62fc60e6228a4ca9abae28228f35e1bd3ce675013d1dfb828688d50c6e23"},
+    {file = "lxml-4.9.1-cp27-cp27m-macosx_10_15_x86_64.whl", hash = "sha256:98cafc618614d72b02185ac583c6f7796202062c41d2eeecdf07820bad3295ed"},
+    {file = "lxml-4.9.1-cp27-cp27m-manylinux_2_5_i686.manylinux1_i686.whl", hash = "sha256:c62e8dd9754b7debda0c5ba59d34509c4688f853588d75b53c3791983faa96fc"},
+    {file = "lxml-4.9.1-cp27-cp27m-manylinux_2_5_x86_64.manylinux1_x86_64.whl", hash = "sha256:21fb3d24ab430fc538a96e9fbb9b150029914805d551deeac7d7822f64631dfc"},
+    {file = "lxml-4.9.1-cp27-cp27m-win32.whl", hash = "sha256:86e92728ef3fc842c50a5cb1d5ba2bc66db7da08a7af53fb3da79e202d1b2cd3"},
+    {file = "lxml-4.9.1-cp27-cp27m-win_amd64.whl", hash = "sha256:4cfbe42c686f33944e12f45a27d25a492cc0e43e1dc1da5d6a87cbcaf2e95627"},
+    {file = "lxml-4.9.1-cp27-cp27mu-manylinux_2_5_i686.manylinux1_i686.whl", hash = "sha256:dad7b164905d3e534883281c050180afcf1e230c3d4a54e8038aa5cfcf312b84"},
+    {file = "lxml-4.9.1-cp27-cp27mu-manylinux_2_5_x86_64.manylinux1_x86_64.whl", hash = "sha256:a614e4afed58c14254e67862456d212c4dcceebab2eaa44d627c2ca04bf86837"},
+    {file = "lxml-4.9.1-cp310-cp310-manylinux_2_12_i686.manylinux2010_i686.manylinux_2_24_i686.whl", hash = "sha256:f9ced82717c7ec65a67667bb05865ffe38af0e835cdd78728f1209c8fffe0cad"},
+    {file = "lxml-4.9.1-cp310-cp310-manylinux_2_17_aarch64.manylinux2014_aarch64.manylinux_2_24_aarch64.whl", hash = "sha256:d9fc0bf3ff86c17348dfc5d322f627d78273eba545db865c3cd14b3f19e57fa5"},
+    {file = "lxml-4.9.1-cp310-cp310-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_24_x86_64.whl", hash = "sha256:e5f66bdf0976ec667fc4594d2812a00b07ed14d1b44259d19a41ae3fff99f2b8"},
+    {file = "lxml-4.9.1-cp310-cp310-musllinux_1_1_aarch64.whl", hash = "sha256:fe17d10b97fdf58155f858606bddb4e037b805a60ae023c009f760d8361a4eb8"},
+    {file = "lxml-4.9.1-cp310-cp310-musllinux_1_1_x86_64.whl", hash = "sha256:8caf4d16b31961e964c62194ea3e26a0e9561cdf72eecb1781458b67ec83423d"},
+    {file = "lxml-4.9.1-cp310-cp310-win32.whl", hash = "sha256:4780677767dd52b99f0af1f123bc2c22873d30b474aa0e2fc3fe5e02217687c7"},
+    {file = "lxml-4.9.1-cp310-cp310-win_amd64.whl", hash = "sha256:b122a188cd292c4d2fcd78d04f863b789ef43aa129b233d7c9004de08693728b"},
+    {file = "lxml-4.9.1-cp311-cp311-manylinux_2_12_i686.manylinux2010_i686.manylinux_2_24_i686.whl", hash = "sha256:be9eb06489bc975c38706902cbc6888f39e946b81383abc2838d186f0e8b6a9d"},
+    {file = "lxml-4.9.1-cp311-cp311-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_24_x86_64.whl", hash = "sha256:f1be258c4d3dc609e654a1dc59d37b17d7fef05df912c01fc2e15eb43a9735f3"},
+    {file = "lxml-4.9.1-cp311-cp311-musllinux_1_1_x86_64.whl", hash = "sha256:927a9dd016d6033bc12e0bf5dee1dde140235fc8d0d51099353c76081c03dc29"},
+    {file = "lxml-4.9.1-cp35-cp35m-manylinux_2_5_i686.manylinux1_i686.whl", hash = "sha256:9232b09f5efee6a495a99ae6824881940d6447debe272ea400c02e3b68aad85d"},
+    {file = "lxml-4.9.1-cp35-cp35m-manylinux_2_5_x86_64.manylinux1_x86_64.whl", hash = "sha256:04da965dfebb5dac2619cb90fcf93efdb35b3c6994fea58a157a834f2f94b318"},
+    {file = "lxml-4.9.1-cp35-cp35m-win32.whl", hash = "sha256:4d5bae0a37af799207140652a700f21a85946f107a199bcb06720b13a4f1f0b7"},
+    {file = "lxml-4.9.1-cp35-cp35m-win_amd64.whl", hash = "sha256:4878e667ebabe9b65e785ac8da4d48886fe81193a84bbe49f12acff8f7a383a4"},
+    {file = "lxml-4.9.1-cp36-cp36m-macosx_10_15_x86_64.whl", hash = "sha256:1355755b62c28950f9ce123c7a41460ed9743c699905cbe664a5bcc5c9c7c7fb"},
+    {file = "lxml-4.9.1-cp36-cp36m-manylinux_2_12_i686.manylinux2010_i686.manylinux_2_24_i686.whl", hash = "sha256:bcaa1c495ce623966d9fc8a187da80082334236a2a1c7e141763ffaf7a405067"},
+    {file = "lxml-4.9.1-cp36-cp36m-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:6eafc048ea3f1b3c136c71a86db393be36b5b3d9c87b1c25204e7d397cee9536"},
+    {file = "lxml-4.9.1-cp36-cp36m-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_24_x86_64.whl", hash = "sha256:13c90064b224e10c14dcdf8086688d3f0e612db53766e7478d7754703295c7c8"},
+    {file = "lxml-4.9.1-cp36-cp36m-manylinux_2_5_i686.manylinux1_i686.whl", hash = "sha256:206a51077773c6c5d2ce1991327cda719063a47adc02bd703c56a662cdb6c58b"},
+    {file = "lxml-4.9.1-cp36-cp36m-manylinux_2_5_x86_64.manylinux1_x86_64.whl", hash = "sha256:e8f0c9d65da595cfe91713bc1222af9ecabd37971762cb830dea2fc3b3bb2acf"},
+    {file = "lxml-4.9.1-cp36-cp36m-musllinux_1_1_aarch64.whl", hash = "sha256:8f0a4d179c9a941eb80c3a63cdb495e539e064f8054230844dcf2fcb812b71d3"},
+    {file = "lxml-4.9.1-cp36-cp36m-musllinux_1_1_x86_64.whl", hash = "sha256:830c88747dce8a3e7525defa68afd742b4580df6aa2fdd6f0855481e3994d391"},
+    {file = "lxml-4.9.1-cp36-cp36m-win32.whl", hash = "sha256:1e1cf47774373777936c5aabad489fef7b1c087dcd1f426b621fda9dcc12994e"},
+    {file = "lxml-4.9.1-cp36-cp36m-win_amd64.whl", hash = "sha256:5974895115737a74a00b321e339b9c3f45c20275d226398ae79ac008d908bff7"},
+    {file = "lxml-4.9.1-cp37-cp37m-macosx_10_15_x86_64.whl", hash = "sha256:1423631e3d51008871299525b541413c9b6c6423593e89f9c4cfbe8460afc0a2"},
+    {file = "lxml-4.9.1-cp37-cp37m-manylinux_2_12_i686.manylinux2010_i686.manylinux_2_24_i686.whl", hash = "sha256:2aaf6a0a6465d39b5ca69688fce82d20088c1838534982996ec46633dc7ad6cc"},
+    {file = "lxml-4.9.1-cp37-cp37m-manylinux_2_17_aarch64.manylinux2014_aarch64.manylinux_2_24_aarch64.whl", hash = "sha256:9f36de4cd0c262dd9927886cc2305aa3f2210db437aa4fed3fb4940b8bf4592c"},
+    {file = "lxml-4.9.1-cp37-cp37m-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_24_x86_64.whl", hash = "sha256:ae06c1e4bc60ee076292e582a7512f304abdf6c70db59b56745cca1684f875a4"},
+    {file = "lxml-4.9.1-cp37-cp37m-manylinux_2_5_i686.manylinux1_i686.whl", hash = "sha256:57e4d637258703d14171b54203fd6822fda218c6c2658a7d30816b10995f29f3"},
+    {file = "lxml-4.9.1-cp37-cp37m-manylinux_2_5_x86_64.manylinux1_x86_64.whl", hash = "sha256:6d279033bf614953c3fc4a0aa9ac33a21e8044ca72d4fa8b9273fe75359d5cca"},
+    {file = "lxml-4.9.1-cp37-cp37m-musllinux_1_1_aarch64.whl", hash = "sha256:a60f90bba4c37962cbf210f0188ecca87daafdf60271f4c6948606e4dabf8785"},
+    {file = "lxml-4.9.1-cp37-cp37m-musllinux_1_1_x86_64.whl", hash = "sha256:6ca2264f341dd81e41f3fffecec6e446aa2121e0b8d026fb5130e02de1402785"},
+    {file = "lxml-4.9.1-cp37-cp37m-win32.whl", hash = "sha256:27e590352c76156f50f538dbcebd1925317a0f70540f7dc8c97d2931c595783a"},
+    {file = "lxml-4.9.1-cp37-cp37m-win_amd64.whl", hash = "sha256:eea5d6443b093e1545ad0210e6cf27f920482bfcf5c77cdc8596aec73523bb7e"},
+    {file = "lxml-4.9.1-cp38-cp38-macosx_10_15_x86_64.whl", hash = "sha256:f05251bbc2145349b8d0b77c0d4e5f3b228418807b1ee27cefb11f69ed3d233b"},
+    {file = "lxml-4.9.1-cp38-cp38-manylinux_2_12_i686.manylinux2010_i686.manylinux_2_24_i686.whl", hash = "sha256:487c8e61d7acc50b8be82bda8c8d21d20e133c3cbf41bd8ad7eb1aaeb3f07c97"},
+    {file = "lxml-4.9.1-cp38-cp38-manylinux_2_17_aarch64.manylinux2014_aarch64.manylinux_2_24_aarch64.whl", hash = "sha256:8d1a92d8e90b286d491e5626af53afef2ba04da33e82e30744795c71880eaa21"},
+    {file = "lxml-4.9.1-cp38-cp38-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_24_x86_64.whl", hash = "sha256:b570da8cd0012f4af9fa76a5635cd31f707473e65a5a335b186069d5c7121ff2"},
+    {file = "lxml-4.9.1-cp38-cp38-manylinux_2_5_i686.manylinux1_i686.whl", hash = "sha256:5ef87fca280fb15342726bd5f980f6faf8b84a5287fcc2d4962ea8af88b35130"},
+    {file = "lxml-4.9.1-cp38-cp38-manylinux_2_5_x86_64.manylinux1_x86_64.whl", hash = "sha256:93e414e3206779ef41e5ff2448067213febf260ba747fc65389a3ddaa3fb8715"},
+    {file = "lxml-4.9.1-cp38-cp38-musllinux_1_1_aarch64.whl", hash = "sha256:6653071f4f9bac46fbc30f3c7838b0e9063ee335908c5d61fb7a4a86c8fd2036"},
+    {file = "lxml-4.9.1-cp38-cp38-musllinux_1_1_x86_64.whl", hash = "sha256:32a73c53783becdb7eaf75a2a1525ea8e49379fb7248c3eeefb9412123536387"},
+    {file = "lxml-4.9.1-cp38-cp38-win32.whl", hash = "sha256:1a7c59c6ffd6ef5db362b798f350e24ab2cfa5700d53ac6681918f314a4d3b94"},
+    {file = "lxml-4.9.1-cp38-cp38-win_amd64.whl", hash = "sha256:1436cf0063bba7888e43f1ba8d58824f085410ea2025befe81150aceb123e345"},
+    {file = "lxml-4.9.1-cp39-cp39-macosx_10_15_x86_64.whl", hash = "sha256:4beea0f31491bc086991b97517b9683e5cfb369205dac0148ef685ac12a20a67"},
+    {file = "lxml-4.9.1-cp39-cp39-manylinux_2_12_i686.manylinux2010_i686.manylinux_2_24_i686.whl", hash = "sha256:41fb58868b816c202e8881fd0f179a4644ce6e7cbbb248ef0283a34b73ec73bb"},
+    {file = "lxml-4.9.1-cp39-cp39-manylinux_2_17_aarch64.manylinux2014_aarch64.manylinux_2_24_aarch64.whl", hash = "sha256:bd34f6d1810d9354dc7e35158aa6cc33456be7706df4420819af6ed966e85448"},
+    {file = "lxml-4.9.1-cp39-cp39-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_24_x86_64.whl", hash = "sha256:edffbe3c510d8f4bf8640e02ca019e48a9b72357318383ca60e3330c23aaffc7"},
+    {file = "lxml-4.9.1-cp39-cp39-manylinux_2_5_i686.manylinux1_i686.whl", hash = "sha256:6d949f53ad4fc7cf02c44d6678e7ff05ec5f5552b235b9e136bd52e9bf730b91"},
+    {file = "lxml-4.9.1-cp39-cp39-manylinux_2_5_x86_64.manylinux1_x86_64.whl", hash = "sha256:079b68f197c796e42aa80b1f739f058dcee796dc725cc9a1be0cdb08fc45b000"},
+    {file = "lxml-4.9.1-cp39-cp39-musllinux_1_1_aarch64.whl", hash = "sha256:9c3a88d20e4fe4a2a4a84bf439a5ac9c9aba400b85244c63a1ab7088f85d9d25"},
+    {file = "lxml-4.9.1-cp39-cp39-musllinux_1_1_x86_64.whl", hash = "sha256:4e285b5f2bf321fc0857b491b5028c5f276ec0c873b985d58d7748ece1d770dd"},
+    {file = "lxml-4.9.1-cp39-cp39-win32.whl", hash = "sha256:ef72013e20dd5ba86a8ae1aed7f56f31d3374189aa8b433e7b12ad182c0d2dfb"},
+    {file = "lxml-4.9.1-cp39-cp39-win_amd64.whl", hash = "sha256:10d2017f9150248563bb579cd0d07c61c58da85c922b780060dcc9a3aa9f432d"},
+    {file = "lxml-4.9.1-pp37-pypy37_pp73-macosx_10_15_x86_64.whl", hash = "sha256:0538747a9d7827ce3e16a8fdd201a99e661c7dee3c96c885d8ecba3c35d1032c"},
+    {file = "lxml-4.9.1-pp37-pypy37_pp73-manylinux_2_12_i686.manylinux2010_i686.manylinux_2_24_i686.whl", hash = "sha256:0645e934e940107e2fdbe7c5b6fb8ec6232444260752598bc4d09511bd056c0b"},
+    {file = "lxml-4.9.1-pp37-pypy37_pp73-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_24_x86_64.whl", hash = "sha256:6daa662aba22ef3258934105be2dd9afa5bb45748f4f702a3b39a5bf53a1f4dc"},
+    {file = "lxml-4.9.1-pp38-pypy38_pp73-macosx_10_15_x86_64.whl", hash = "sha256:603a464c2e67d8a546ddaa206d98e3246e5db05594b97db844c2f0a1af37cf5b"},
+    {file = "lxml-4.9.1-pp38-pypy38_pp73-manylinux_2_12_i686.manylinux2010_i686.manylinux_2_24_i686.whl", hash = "sha256:c4b2e0559b68455c085fb0f6178e9752c4be3bba104d6e881eb5573b399d1eb2"},
+    {file = "lxml-4.9.1-pp38-pypy38_pp73-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_24_x86_64.whl", hash = "sha256:0f3f0059891d3254c7b5fb935330d6db38d6519ecd238ca4fce93c234b4a0f73"},
+    {file = "lxml-4.9.1-pp39-pypy39_pp73-manylinux_2_12_i686.manylinux2010_i686.manylinux_2_24_i686.whl", hash = "sha256:c852b1530083a620cb0de5f3cd6826f19862bafeaf77586f1aef326e49d95f0c"},
+    {file = "lxml-4.9.1-pp39-pypy39_pp73-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_24_x86_64.whl", hash = "sha256:287605bede6bd36e930577c5925fcea17cb30453d96a7b4c63c14a257118dbb9"},
+    {file = "lxml-4.9.1.tar.gz", hash = "sha256:fe749b052bb7233fe5d072fcb549221a8cb1a16725c47c37e42b0b9cb3ff2c3f"},
 ]
 markupsafe = [
    {file = "MarkupSafe-2.1.0-cp310-cp310-macosx_10_9_universal2.whl", hash = "sha256:3028252424c72b2602a323f70fbf50aa80a5d3aa616ea6add4ba21ae9cc9da4c"},
--- a/pyproject.toml
+++ b/pyproject.toml
@ -54,7 +54,7 @@ skip_gitignore = true

 [tool.poetry]
 name = "matrix-synapse"
-version = "1.62.0"
+version = "1.63.0rc1"
 description = "Homeserver for the Matrix decentralised comms protocol"
 authors = ["Matrix.org Team and Contributors <packages@matrix.org>"]
 license = "Apache-2.0"
--- a/requirements.txt
+++ b/requirements.txt
@ -249,68 +249,77 @@ jinja2==3.0.3 \
 jsonschema==4.4.0 \
    --hash=sha256:77281a1f71684953ee8b3d488371b162419767973789272434bbc3f29d9c8823 \
    --hash=sha256:636694eb41b3535ed608fe04129f26542b59ed99808b4f688aa32dcf55317a83
-lxml==4.8.0 \
-    --hash=sha256:e1ab2fac607842ac36864e358c42feb0960ae62c34aa4caaf12ada0a1fb5d99b \
-    --hash=sha256:28d1af847786f68bec57961f31221125c29d6f52d9187c01cd34dc14e2b29430 \
-    --hash=sha256:b92d40121dcbd74831b690a75533da703750f7041b4bf951befc657c37e5695a \
-    --hash=sha256:e01f9531ba5420838c801c21c1b0f45dbc9607cb22ea2cf132844453bec863a5 \
-    --hash=sha256:6259b511b0f2527e6d55ad87acc1c07b3cbffc3d5e050d7e7bcfa151b8202df9 \
-    --hash=sha256:1010042bfcac2b2dc6098260a2ed022968dbdfaf285fc65a3acf8e4eb1ffd1bc \
-    --hash=sha256:fa56bb08b3dd8eac3a8c5b7d075c94e74f755fd9d8a04543ae8d37b1612dd170 \
-    --hash=sha256:31ba2cbc64516dcdd6c24418daa7abff989ddf3ba6d3ea6f6ce6f2ed6e754ec9 \
-    --hash=sha256:31499847fc5f73ee17dbe1b8e24c6dafc4e8d5b48803d17d22988976b0171f03 \
-    --hash=sha256:5f7d7d9afc7b293147e2d506a4596641d60181a35279ef3aa5778d0d9d9123fe \
-    --hash=sha256:a3c5f1a719aa11866ffc530d54ad965063a8cbbecae6515acbd5f0fae8f48eaa \
-    --hash=sha256:6268e27873a3d191849204d00d03f65c0e343b3bcb518a6eaae05677c95621d1 \
-    --hash=sha256:330bff92c26d4aee79c5bc4d9967858bdbe73fdbdbacb5daf623a03a914fe05b \
-    --hash=sha256:b2582b238e1658c4061ebe1b4df53c435190d22457642377fd0cb30685cdfb76 \
-    --hash=sha256:a2bfc7e2a0601b475477c954bf167dee6d0f55cb167e3f3e7cefad906e7759f6 \
-    --hash=sha256:a1547ff4b8a833511eeaceacbcd17b043214fcdb385148f9c1bc5556ca9623e2 \
-    --hash=sha256:a9f1c3489736ff8e1c7652e9dc39f80cff820f23624f23d9eab6e122ac99b150 \
-    --hash=sha256:530f278849031b0eb12f46cca0e5db01cfe5177ab13bd6878c6e739319bae654 \
-    --hash=sha256:078306d19a33920004addeb5f4630781aaeabb6a8d01398045fcde085091a169 \
-    --hash=sha256:86545e351e879d0b72b620db6a3b96346921fa87b3d366d6c074e5a9a0b8dadb \
-    --hash=sha256:24f5c5ae618395ed871b3d8ebfcbb36e3f1091fd847bf54c4de623f9107942f3 \
-    --hash=sha256:bbab6faf6568484707acc052f4dfc3802bdb0cafe079383fbaa23f1cdae9ecd4 \
-    --hash=sha256:7993232bd4044392c47779a3c7e8889fea6883be46281d45a81451acfd704d7e \
-    --hash=sha256:6d6483b1229470e1d8835e52e0ff3c6973b9b97b24cd1c116dca90b57a2cc613 \
-    --hash=sha256:ad4332a532e2d5acb231a2e5d33f943750091ee435daffca3fec0a53224e7e33 \
-    --hash=sha256:db3535733f59e5605a88a706824dfcb9bd06725e709ecb017e165fc1d6e7d429 \
-    --hash=sha256:5f148b0c6133fb928503cfcdfdba395010f997aa44bcf6474fcdd0c5398d9b63 \
-    --hash=sha256:8a31f24e2a0b6317f33aafbb2f0895c0bce772980ae60c2c640d82caac49628a \
-    --hash=sha256:719544565c2937c21a6f76d520e6e52b726d132815adb3447ccffbe9f44203c4 \
-    --hash=sha256:c0b88ed1ae66777a798dc54f627e32d3b81c8009967c63993c450ee4cbcbec15 \
-    --hash=sha256:fa9b7c450be85bfc6cd39f6df8c5b8cbd76b5d6fc1f69efec80203f9894b885f \
-    --hash=sha256:e9f84ed9f4d50b74fbc77298ee5c870f67cb7e91dcdc1a6915cb1ff6a317476c \
-    --hash=sha256:1d650812b52d98679ed6c6b3b55cbb8fe5a5460a0aef29aeb08dc0b44577df85 \
-    --hash=sha256:80bbaddf2baab7e6de4bc47405e34948e694a9efe0861c61cdc23aa774fcb141 \
-    --hash=sha256:6f7b82934c08e28a2d537d870293236b1000d94d0b4583825ab9649aef7ddf63 \
-    --hash=sha256:e1fd7d2fe11f1cb63d3336d147c852f6d07de0d0020d704c6031b46a30b02ca8 \
-    --hash=sha256:5045ee1ccd45a89c4daec1160217d363fcd23811e26734688007c26f28c9e9e7 \
-    --hash=sha256:0c1978ff1fd81ed9dcbba4f91cf09faf1f8082c9d72eb122e92294716c605428 \
-    --hash=sha256:52cbf2ff155b19dc4d4100f7442f6a697938bf4493f8d3b0c51d45568d5666b5 \
-    --hash=sha256:ce13d6291a5f47c1c8dbd375baa78551053bc6b5e5c0e9bb8e39c0a8359fd52f \
-    --hash=sha256:e11527dc23d5ef44d76fef11213215c34f36af1608074561fcc561d983aeb870 \
-    --hash=sha256:60d2f60bd5a2a979df28ab309352cdcf8181bda0cca4529769a945f09aba06f9 \
-    --hash=sha256:62f93eac69ec0f4be98d1b96f4d6b964855b8255c345c17ff12c20b93f247b68 \
-    --hash=sha256:20b8a746a026017acf07da39fdb10aa80ad9877046c9182442bf80c84a1c4696 \
-    --hash=sha256:891dc8f522d7059ff0024cd3ae79fd224752676447f9c678f2a5c14b84d9a939 \
-    --hash=sha256:b6fc2e2fb6f532cf48b5fed57567ef286addcef38c28874458a41b7837a57807 \
-    --hash=sha256:74eb65ec61e3c7c019d7169387d1b6ffcfea1b9ec5894d116a9a903636e4a0b1 \
-    --hash=sha256:627e79894770783c129cc5e89b947e52aa26e8e0557c7e205368a809da4b7939 \
-    --hash=sha256:545bd39c9481f2e3f2727c78c169425efbfb3fbba6e7db4f46a80ebb249819ca \
-    --hash=sha256:5a58d0b12f5053e270510bf12f753a76aaf3d74c453c00942ed7d2c804ca845c \
-    --hash=sha256:ec4b4e75fc68da9dc0ed73dcdb431c25c57775383fec325d23a770a64e7ebc87 \
-    --hash=sha256:5804e04feb4e61babf3911c2a974a5b86f66ee227cc5006230b00ac6d285b3a9 \
-    --hash=sha256:aa0cf4922da7a3c905d000b35065df6184c0dc1d866dd3b86fd961905bbad2ea \
-    --hash=sha256:dd10383f1d6b7edf247d0960a3db274c07e96cf3a3fc7c41c8448f93eac3fb1c \
-    --hash=sha256:2403a6d6fb61c285969b71f4a3527873fe93fd0abe0832d858a17fe68c8fa507 \
-    --hash=sha256:986b7a96228c9b4942ec420eff37556c5777bfba6758edcb95421e4a614b57f9 \
-    --hash=sha256:6fe4ef4402df0250b75ba876c3795510d782def5c1e63890bde02d622570d39e \
-    --hash=sha256:f10ce66fcdeb3543df51d423ede7e238be98412232fca5daec3e54bcd16b8da0 \
-    --hash=sha256:730766072fd5dcb219dd2b95c4c49752a54f00157f322bc6d71f7d2a31fecd79 \
-    --hash=sha256:8b99ec73073b37f9ebe8caf399001848fced9c08064effdbfc4da2b5a8d07b93 \
-    --hash=sha256:f63f62fc60e6228a4ca9abae28228f35e1bd3ce675013d1dfb828688d50c6e23
+lxml==4.9.1 \
+    --hash=sha256:98cafc618614d72b02185ac583c6f7796202062c41d2eeecdf07820bad3295ed \
+    --hash=sha256:c62e8dd9754b7debda0c5ba59d34509c4688f853588d75b53c3791983faa96fc \
+    --hash=sha256:21fb3d24ab430fc538a96e9fbb9b150029914805d551deeac7d7822f64631dfc \
+    --hash=sha256:86e92728ef3fc842c50a5cb1d5ba2bc66db7da08a7af53fb3da79e202d1b2cd3 \
+    --hash=sha256:4cfbe42c686f33944e12f45a27d25a492cc0e43e1dc1da5d6a87cbcaf2e95627 \
+    --hash=sha256:dad7b164905d3e534883281c050180afcf1e230c3d4a54e8038aa5cfcf312b84 \
+    --hash=sha256:a614e4afed58c14254e67862456d212c4dcceebab2eaa44d627c2ca04bf86837 \
+    --hash=sha256:f9ced82717c7ec65a67667bb05865ffe38af0e835cdd78728f1209c8fffe0cad \
+    --hash=sha256:d9fc0bf3ff86c17348dfc5d322f627d78273eba545db865c3cd14b3f19e57fa5 \
+    --hash=sha256:e5f66bdf0976ec667fc4594d2812a00b07ed14d1b44259d19a41ae3fff99f2b8 \
+    --hash=sha256:fe17d10b97fdf58155f858606bddb4e037b805a60ae023c009f760d8361a4eb8 \
+    --hash=sha256:8caf4d16b31961e964c62194ea3e26a0e9561cdf72eecb1781458b67ec83423d \
+    --hash=sha256:4780677767dd52b99f0af1f123bc2c22873d30b474aa0e2fc3fe5e02217687c7 \
+    --hash=sha256:b122a188cd292c4d2fcd78d04f863b789ef43aa129b233d7c9004de08693728b \
+    --hash=sha256:be9eb06489bc975c38706902cbc6888f39e946b81383abc2838d186f0e8b6a9d \
+    --hash=sha256:f1be258c4d3dc609e654a1dc59d37b17d7fef05df912c01fc2e15eb43a9735f3 \
+    --hash=sha256:927a9dd016d6033bc12e0bf5dee1dde140235fc8d0d51099353c76081c03dc29 \
+    --hash=sha256:9232b09f5efee6a495a99ae6824881940d6447debe272ea400c02e3b68aad85d \
+    --hash=sha256:04da965dfebb5dac2619cb90fcf93efdb35b3c6994fea58a157a834f2f94b318 \
+    --hash=sha256:4d5bae0a37af799207140652a700f21a85946f107a199bcb06720b13a4f1f0b7 \
+    --hash=sha256:4878e667ebabe9b65e785ac8da4d48886fe81193a84bbe49f12acff8f7a383a4 \
+    --hash=sha256:1355755b62c28950f9ce123c7a41460ed9743c699905cbe664a5bcc5c9c7c7fb \
+    --hash=sha256:bcaa1c495ce623966d9fc8a187da80082334236a2a1c7e141763ffaf7a405067 \
+    --hash=sha256:6eafc048ea3f1b3c136c71a86db393be36b5b3d9c87b1c25204e7d397cee9536 \
+    --hash=sha256:13c90064b224e10c14dcdf8086688d3f0e612db53766e7478d7754703295c7c8 \
+    --hash=sha256:206a51077773c6c5d2ce1991327cda719063a47adc02bd703c56a662cdb6c58b \
+    --hash=sha256:e8f0c9d65da595cfe91713bc1222af9ecabd37971762cb830dea2fc3b3bb2acf \
+    --hash=sha256:8f0a4d179c9a941eb80c3a63cdb495e539e064f8054230844dcf2fcb812b71d3 \
+    --hash=sha256:830c88747dce8a3e7525defa68afd742b4580df6aa2fdd6f0855481e3994d391 \
+    --hash=sha256:1e1cf47774373777936c5aabad489fef7b1c087dcd1f426b621fda9dcc12994e \
+    --hash=sha256:5974895115737a74a00b321e339b9c3f45c20275d226398ae79ac008d908bff7 \
+    --hash=sha256:1423631e3d51008871299525b541413c9b6c6423593e89f9c4cfbe8460afc0a2 \
+    --hash=sha256:2aaf6a0a6465d39b5ca69688fce82d20088c1838534982996ec46633dc7ad6cc \
+    --hash=sha256:9f36de4cd0c262dd9927886cc2305aa3f2210db437aa4fed3fb4940b8bf4592c \
+    --hash=sha256:ae06c1e4bc60ee076292e582a7512f304abdf6c70db59b56745cca1684f875a4 \
+    --hash=sha256:57e4d637258703d14171b54203fd6822fda218c6c2658a7d30816b10995f29f3 \
+    --hash=sha256:6d279033bf614953c3fc4a0aa9ac33a21e8044ca72d4fa8b9273fe75359d5cca \
+    --hash=sha256:a60f90bba4c37962cbf210f0188ecca87daafdf60271f4c6948606e4dabf8785 \
+    --hash=sha256:6ca2264f341dd81e41f3fffecec6e446aa2121e0b8d026fb5130e02de1402785 \
+    --hash=sha256:27e590352c76156f50f538dbcebd1925317a0f70540f7dc8c97d2931c595783a \
+    --hash=sha256:eea5d6443b093e1545ad0210e6cf27f920482bfcf5c77cdc8596aec73523bb7e \
+    --hash=sha256:f05251bbc2145349b8d0b77c0d4e5f3b228418807b1ee27cefb11f69ed3d233b \
+    --hash=sha256:487c8e61d7acc50b8be82bda8c8d21d20e133c3cbf41bd8ad7eb1aaeb3f07c97 \
+    --hash=sha256:8d1a92d8e90b286d491e5626af53afef2ba04da33e82e30744795c71880eaa21 \
+    --hash=sha256:b570da8cd0012f4af9fa76a5635cd31f707473e65a5a335b186069d5c7121ff2 \
+    --hash=sha256:5ef87fca280fb15342726bd5f980f6faf8b84a5287fcc2d4962ea8af88b35130 \
+    --hash=sha256:93e414e3206779ef41e5ff2448067213febf260ba747fc65389a3ddaa3fb8715 \
+    --hash=sha256:6653071f4f9bac46fbc30f3c7838b0e9063ee335908c5d61fb7a4a86c8fd2036 \
+    --hash=sha256:32a73c53783becdb7eaf75a2a1525ea8e49379fb7248c3eeefb9412123536387 \
+    --hash=sha256:1a7c59c6ffd6ef5db362b798f350e24ab2cfa5700d53ac6681918f314a4d3b94 \
+    --hash=sha256:1436cf0063bba7888e43f1ba8d58824f085410ea2025befe81150aceb123e345 \
+    --hash=sha256:4beea0f31491bc086991b97517b9683e5cfb369205dac0148ef685ac12a20a67 \
+    --hash=sha256:41fb58868b816c202e8881fd0f179a4644ce6e7cbbb248ef0283a34b73ec73bb \
+    --hash=sha256:bd34f6d1810d9354dc7e35158aa6cc33456be7706df4420819af6ed966e85448 \
+    --hash=sha256:edffbe3c510d8f4bf8640e02ca019e48a9b72357318383ca60e3330c23aaffc7 \
+    --hash=sha256:6d949f53ad4fc7cf02c44d6678e7ff05ec5f5552b235b9e136bd52e9bf730b91 \
+    --hash=sha256:079b68f197c796e42aa80b1f739f058dcee796dc725cc9a1be0cdb08fc45b000 \
+    --hash=sha256:9c3a88d20e4fe4a2a4a84bf439a5ac9c9aba400b85244c63a1ab7088f85d9d25 \
+    --hash=sha256:4e285b5f2bf321fc0857b491b5028c5f276ec0c873b985d58d7748ece1d770dd \
+    --hash=sha256:ef72013e20dd5ba86a8ae1aed7f56f31d3374189aa8b433e7b12ad182c0d2dfb \
+    --hash=sha256:10d2017f9150248563bb579cd0d07c61c58da85c922b780060dcc9a3aa9f432d \
+    --hash=sha256:0538747a9d7827ce3e16a8fdd201a99e661c7dee3c96c885d8ecba3c35d1032c \
+    --hash=sha256:0645e934e940107e2fdbe7c5b6fb8ec6232444260752598bc4d09511bd056c0b \
+    --hash=sha256:6daa662aba22ef3258934105be2dd9afa5bb45748f4f702a3b39a5bf53a1f4dc \
+    --hash=sha256:603a464c2e67d8a546ddaa206d98e3246e5db05594b97db844c2f0a1af37cf5b \
+    --hash=sha256:c4b2e0559b68455c085fb0f6178e9752c4be3bba104d6e881eb5573b399d1eb2 \
+    --hash=sha256:0f3f0059891d3254c7b5fb935330d6db38d6519ecd238ca4fce93c234b4a0f73 \
+    --hash=sha256:c852b1530083a620cb0de5f3cd6826f19862bafeaf77586f1aef326e49d95f0c \
+    --hash=sha256:287605bede6bd36e930577c5925fcea17cb30453d96a7b4c63c14a257118dbb9 \
+    --hash=sha256:fe749b052bb7233fe5d072fcb549221a8cb1a16725c47c37e42b0b9cb3ff2c3f
 markupsafe==2.1.0 ; python_version >= "3.7" \
    --hash=sha256:3028252424c72b2602a323f70fbf50aa80a5d3aa616ea6add4ba21ae9cc9da4c \
    --hash=sha256:290b02bab3c9e216da57c1d11d2ba73a9f73a614bbdcc027d299a60cdfabb11a \
--- a/scripts-dev/complement.sh
+++ b/scripts-dev/complement.sh
@ -14,12 +14,18 @@
 # By default Synapse is run in monolith mode. This can be overridden by
 # setting the WORKERS environment variable.
 #
-# A regular expression of test method names can be supplied as the first
-# argument to the script. Complement will then only run those tests. If
-# no regex is supplied, all tests are run. For example;
+# You can optionally give a "-f" argument (for "fast") before any to skip
+# rebuilding the docker images, if you just want to rerun the tests.
+#
+# Remaining commandline arguments are passed through to `go test`. For example,
+# you can supply a regular expression of test method names via the "-run"
+# argument:
 #
 # ./complement.sh -run "TestOutboundFederation(Profile|Send)"
 #
+# Specifying TEST_ONLY_SKIP_DEP_HASH_VERIFICATION=1 will cause `poetry export`
+# to not emit any hashes when building the Docker image. This then means that
+# you can use 'unverifiable' sources such as git repositories as dependencies.

 # Exit if a line returns a non-zero exit code
 set -e
@ -32,6 +38,47 @@ echo_if_github() {
  fi
 }

+# Helper to print out the usage instructions
+usage() {
+    cat >&2 <<EOF
+Usage: $0 [-f] <go test arguments>...
+Run the complement test suite on Synapse.
+
+  -f, --fast
+        Skip rebuilding the docker images, and just use the most recent
+        'complement-synapse:latest' image.
+        Conflicts with --build-only.
+
+  --build-only
+        Only build the Docker images. Don't actually run Complement.
+        Conflicts with -f/--fast.
+
+For help on arguments to 'go test', run 'go help testflag'.
+EOF
+}
+
+# parse our arguments
+skip_docker_build=""
+skip_complement_run=""
+while [ $# -ge 1 ]; do
+    arg=$1
+    case "$arg" in
+        "-h")
+            usage
+            exit 1
+            ;;
+        "-f"|"--fast")
+            skip_docker_build=1
+            ;;
+        "--build-only")
+            skip_complement_run=1
+            ;;
+        *)
+            # unknown arg: presumably an argument to gotest. break the loop.
+            break
+    esac
+    shift
+done

 # enable buildkit for the docker builds
 export DOCKER_BUILDKIT=1
@ -49,21 +96,30 @@ if [[ -z "$COMPLEMENT_DIR" ]]; then
  echo "Checkout available at 'complement-${COMPLEMENT_REF}'"
 fi

-# Build the base Synapse image from the local checkout
-echo_if_github "::group::Build Docker image: matrixdotorg/synapse"
-docker build -t matrixdotorg/synapse -f "docker/Dockerfile" .
-echo_if_github "::endgroup::"
+if [ -z "$skip_docker_build" ]; then
+    # Build the base Synapse image from the local checkout
+    echo_if_github "::group::Build Docker image: matrixdotorg/synapse"
+    docker build -t matrixdotorg/synapse \
+      --build-arg TEST_ONLY_SKIP_DEP_HASH_VERIFICATION \
+      -f "docker/Dockerfile" .
+    echo_if_github "::endgroup::"

-# Build the workers docker image (from the base Synapse image we just built).
-echo_if_github "::group::Build Docker image: matrixdotorg/synapse-workers"
-docker build -t matrixdotorg/synapse-workers -f "docker/Dockerfile-workers" .
-echo_if_github "::endgroup::"
+    # Build the workers docker image (from the base Synapse image we just built).
+    echo_if_github "::group::Build Docker image: matrixdotorg/synapse-workers"
+    docker build -t matrixdotorg/synapse-workers -f "docker/Dockerfile-workers" .
+    echo_if_github "::endgroup::"

-# Build the unified Complement image (from the worker Synapse image we just built).
-echo_if_github "::group::Build Docker image: complement/Dockerfile"
-docker build -t complement-synapse \
-  -f "docker/complement/Dockerfile" "docker/complement"
-echo_if_github "::endgroup::"
+    # Build the unified Complement image (from the worker Synapse image we just built).
+    echo_if_github "::group::Build Docker image: complement/Dockerfile"
+    docker build -t complement-synapse \
+           -f "docker/complement/Dockerfile" "docker/complement"
+    echo_if_github "::endgroup::"
+fi
+
+if [ -n "$skip_complement_run" ]; then
+    echo "Skipping Complement run as requested."
+    exit
+fi

 export COMPLEMENT_BASE_IMAGE=complement-synapse

@ -104,6 +160,18 @@ else
  test_tags="$test_tags,faster_joins"
 fi

+
+if [[ -n "$SYNAPSE_TEST_LOG_LEVEL" ]]; then
+  # Set the log level to what is desired
+  export PASS_SYNAPSE_LOG_LEVEL="$SYNAPSE_TEST_LOG_LEVEL"
+
+  # Allow logging sensitive things (currently SQL queries & parameters).
+  # (This won't have any effect if we're not logging at DEBUG level overall.)
+  # Since this is just a test suite, this is fine and won't reveal anyone's
+  # personal information
+  export PASS_SYNAPSE_LOG_SENSITIVE=1
+fi
+
 # Run the tests!
 echo "Images built; running complement"
 cd "$COMPLEMENT_DIR"
--- a/synapse/_scripts/synapse_port_db.py
+++ b/synapse/_scripts/synapse_port_db.py
@ -268,6 +268,9 @@ class MockHomeserver:
    def get_instance_name(self) -> str:
        return "master"

+    def should_send_federation(self) -> bool:
+        return False
+

 class Porter:
    def __init__(
@ -415,12 +418,15 @@ class Porter:
            self.progress.update(table, table_size)  # Mark table as done
            return

+        # We sweep over rowids in two directions: one forwards (rowids 1, 2, 3, ...)
+        # and another backwards (rowids 0, -1, -2, ...).
        forward_select = (
            "SELECT rowid, * FROM %s WHERE rowid >= ? ORDER BY rowid LIMIT ?" % (table,)
        )

        backward_select = (
-            "SELECT rowid, * FROM %s WHERE rowid <= ? ORDER BY rowid LIMIT ?" % (table,)
+            "SELECT rowid, * FROM %s WHERE rowid <= ? ORDER BY rowid DESC LIMIT ?"
+            % (table,)
        )

        do_forward = [True]
@ -618,6 +624,25 @@ class Porter:
                self.postgres_store.db_pool.updates.has_completed_background_updates()
            )

+    @staticmethod
+    def _is_sqlite_autovacuum_enabled(txn: LoggingTransaction) -> bool:
+        """
+        Returns true if auto_vacuum is enabled in SQLite.
+        https://www.sqlite.org/pragma.html#pragma_auto_vacuum
+
+        Vacuuming changes the rowids on rows in the database.
+        Auto-vacuuming is therefore dangerous when used in conjunction with this script.
+
+        Note that the auto_vacuum setting can't be changed without performing
+        a VACUUM after trying to change the pragma.
+        """
+        txn.execute("PRAGMA auto_vacuum")
+        row = txn.fetchone()
+        assert row is not None, "`PRAGMA auto_vacuum` did not give a row."
+        (autovacuum_setting,) = row
+        # 0 means off. 1 means full. 2 means incremental.
+        return autovacuum_setting != 0
+
    async def run(self) -> None:
        """Ports the SQLite database to a PostgreSQL database.

@ -634,6 +659,21 @@ class Porter:
                allow_outdated_version=True,
            )

+            # For safety, ensure auto_vacuums are disabled.
+            if await self.sqlite_store.db_pool.runInteraction(
+                "is_sqlite_autovacuum_enabled", self._is_sqlite_autovacuum_enabled
+            ):
+                end_error = (
+                    "auto_vacuum is enabled in the SQLite database."
+                    " (This is not the default configuration.)\n"
+                    " This script relies on rowids being consistent and must not"
+                    " be used if the database could be vacuumed between re-runs.\n"
+                    " To disable auto_vacuum, you need to stop Synapse and run the following SQL:\n"
+                    " PRAGMA auto_vacuum=off;\n"
+                    " VACUUM;"
+                )
+                return
+
            # Check if all background updates are done, abort if not.
            updates_complete = (
                await self.sqlite_store.db_pool.updates.has_completed_background_updates()
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@ -259,3 +259,13 @@ class ReceiptTypes:
    READ: Final = "m.read"
    READ_PRIVATE: Final = "org.matrix.msc2285.read.private"
    FULLY_READ: Final = "m.fully_read"
+
+
+class PublicRoomsFilterFields:
+    """Fields in the search filter for `/publicRooms` that we understand.
+
+    As defined in https://spec.matrix.org/v1.3/client-server-api/#post_matrixclientv3publicrooms
+    """
+
+    GENERIC_SEARCH_TERM: Final = "generic_search_term"
+    ROOM_TYPES: Final = "org.matrix.msc3827.room_types"
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@ -297,8 +297,14 @@ class AuthError(SynapseError):
    other poorly-defined times.
    """

-    def __init__(self, code: int, msg: str, errcode: str = Codes.FORBIDDEN):
-        super().__init__(code, msg, errcode)
+    def __init__(
+        self,
+        code: int,
+        msg: str,
+        errcode: str = Codes.FORBIDDEN,
+        additional_fields: Optional[dict] = None,
+    ):
+        super().__init__(code, msg, errcode, additional_fields)


 class InvalidClientCredentialsError(SynapseError):
--- a/synapse/app/_base.py
+++ b/synapse/app/_base.py
@ -106,7 +106,9 @@ def register_sighup(func: Callable[P, None], *args: P.args, **kwargs: P.kwargs)
 def start_worker_reactor(
    appname: str,
    config: HomeServerConfig,
-    run_command: Callable[[], None] = reactor.run,
+    # Use a lambda to avoid binding to a given reactor at import time.
+    # (needed when synapse.app.complement_fork_starter is being used)
+    run_command: Callable[[], None] = lambda: reactor.run(),
 ) -> None:
    """Run the reactor in the main process

@ -141,7 +143,9 @@ def start_reactor(
    daemonize: bool,
    print_pidfile: bool,
    logger: logging.Logger,
-    run_command: Callable[[], None] = reactor.run,
+    # Use a lambda to avoid binding to a given reactor at import time.
+    # (needed when synapse.app.complement_fork_starter is being used)
+    run_command: Callable[[], None] = lambda: reactor.run(),
 ) -> None:
    """Run the reactor in the main process

--- a/synapse/app/admin_cmd.py
+++ b/synapse/app/admin_cmd.py
@ -39,6 +39,7 @@ from synapse.replication.slave.storage.push_rule import SlavedPushRuleStore
 from synapse.replication.slave.storage.receipts import SlavedReceiptsStore
 from synapse.replication.slave.storage.registration import SlavedRegistrationStore
 from synapse.server import HomeServer
+from synapse.storage.database import DatabasePool, LoggingDatabaseConnection
 from synapse.storage.databases.main.room import RoomWorkerStore
 from synapse.types import StateMap
 from synapse.util import SYNAPSE_VERSION
@ -60,7 +61,17 @@ class AdminCmdSlavedStore(
    BaseSlavedStore,
    RoomWorkerStore,
 ):
-    pass
+    def __init__(
+        self,
+        database: DatabasePool,
+        db_conn: LoggingDatabaseConnection,
+        hs: "HomeServer",
+    ):
+        super().__init__(database, db_conn, hs)
+
+        # Annoyingly `filter_events_for_client` assumes that this exists. We
+        # should refactor it to take a `Clock` directly.
+        self.clock = hs.get_clock()


 class AdminCmdServer(HomeServer):
--- a/synapse/app/complement_fork_starter.py
+++ b/synapse/app/complement_fork_starter.py
@ -0,0 +1,190 @@
+# Copyright 2022 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# 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.
+#
+# ## What this script does
+#
+# This script spawns multiple workers, whilst only going through the code loading
+# process once. The net effect is that start-up time for a swarm of workers is
+# reduced, particularly in CPU-constrained environments.
+#
+# Before the workers are spawned, the database is prepared in order to avoid the
+# workers racing.
+#
+# ## Stability
+#
+# This script is only intended for use within the Synapse images for the
+# Complement test suite.
+# There are currently no stability guarantees whatsoever; especially not about:
+# - whether it will continue to exist in future versions;
+# - the format of its command-line arguments; or
+# - any details about its behaviour or principles of operation.
+#
+# ## Usage
+#
+# The first argument should be the path to the database configuration, used to
+# set up the database. The rest of the arguments are used as follows:
+# Each worker is specified as an argument group (each argument group is
+# separated by '--').
+# The first argument in each argument group is the Python module name of the application
+# to start. Further arguments are then passed to that module as-is.
+#
+# ## Example
+#
+#   python -m synapse.app.complement_fork_starter path_to_db_config.yaml \
+#     synapse.app.homeserver [args..] -- \
+#     synapse.app.generic_worker [args..] -- \
+#   ...
+#     synapse.app.generic_worker [args..]
+#
+import argparse
+import importlib
+import itertools
+import multiprocessing
+import sys
+from typing import Any, Callable, List
+
+from twisted.internet.main import installReactor
+
+
+class ProxiedReactor:
+    """
+    Twisted tracks the 'installed' reactor as a global variable.
+    (Actually, it does some module trickery, but the effect is similar.)
+
+    The default EpollReactor is buggy if it's created before a process is
+    forked, then used in the child.
+    See https://twistedmatrix.com/trac/ticket/4759#comment:17.
+
+    However, importing certain Twisted modules will automatically create and
+    install a reactor if one hasn't already been installed.
+    It's not normally possible to re-install a reactor.
+
+    Given the goal of launching workers with fork() to only import the code once,
+    this presents a conflict.
+    Our work around is to 'install' this ProxiedReactor which prevents Twisted
+    from creating and installing one, but which lets us replace the actual reactor
+    in use later on.
+    """
+
+    def __init__(self) -> None:
+        self.___reactor_target: Any = None
+
+    def _install_real_reactor(self, new_reactor: Any) -> None:
+        """
+        Install a real reactor for this ProxiedReactor to forward lookups onto.
+
+        This method is specific to our ProxiedReactor and should not clash with
+        any names used on an actual Twisted reactor.
+        """
+        self.___reactor_target = new_reactor
+
+    def __getattr__(self, attr_name: str) -> Any:
+        return getattr(self.___reactor_target, attr_name)
+
+
+def _worker_entrypoint(
+    func: Callable[[], None], proxy_reactor: ProxiedReactor, args: List[str]
+) -> None:
+    """
+    Entrypoint for a forked worker process.
+
+    We just need to set up the command-line arguments, create our real reactor
+    and then kick off the worker's main() function.
+    """
+
+    sys.argv = args
+
+    from twisted.internet.epollreactor import EPollReactor
+
+    proxy_reactor._install_real_reactor(EPollReactor())
+    func()
+
+
+def main() -> None:
+    """
+    Entrypoint for the forking launcher.
+    """
+    parser = argparse.ArgumentParser()
+    parser.add_argument("db_config", help="Path to database config file")
+    parser.add_argument(
+        "args",
+        nargs="...",
+        help="Argument groups separated by `--`. "
+        "The first argument of each group is a Synapse app name. "
+        "Subsequent arguments are passed through.",
+    )
+    ns = parser.parse_args()
+
+    # Split up the subsequent arguments into each workers' arguments;
+    # `--` is our delimiter of choice.
+    args_by_worker: List[List[str]] = [
+        list(args)
+        for cond, args in itertools.groupby(ns.args, lambda ele: ele != "--")
+        if cond and args
+    ]
+
+    # Prevent Twisted from installing a shared reactor that all the workers will
+    # inherit when we fork(), by installing our own beforehand.
+    proxy_reactor = ProxiedReactor()
+    installReactor(proxy_reactor)
+
+    # Import the entrypoints for all the workers.
+    worker_functions = []
+    for worker_args in args_by_worker:
+        worker_module = importlib.import_module(worker_args[0])
+        worker_functions.append(worker_module.main)
+
+    # We need to prepare the database first as otherwise all the workers will
+    # try to create a schema version table and some will crash out.
+    from synapse._scripts import update_synapse_database
+
+    update_proc = multiprocessing.Process(
+        target=_worker_entrypoint,
+        args=(
+            update_synapse_database.main,
+            proxy_reactor,
+            [
+                "update_synapse_database",
+                "--database-config",
+                ns.db_config,
+                "--run-background-updates",
+            ],
+        ),
+    )
+    print("===== PREPARING DATABASE =====", file=sys.stderr)
+    update_proc.start()
+    update_proc.join()
+    print("===== PREPARED DATABASE =====", file=sys.stderr)
+
+    # At this point, we've imported all the main entrypoints for all the workers.
+    # Now we basically just fork() out to create the workers we need.
+    # Because we're using fork(), all the workers get a clone of this launcher's
+    # memory space and don't need to repeat the work of loading the code!
+    # Instead of using fork() directly, we use the multiprocessing library,
+    # which uses fork() on Unix platforms.
+    processes = []
+    for (func, worker_args) in zip(worker_functions, args_by_worker):
+        process = multiprocessing.Process(
+            target=_worker_entrypoint, args=(func, proxy_reactor, worker_args)
+        )
+        process.start()
+        processes.append(process)
+
+    # Be a good parent and wait for our children to die before exiting.
+    for process in processes:
+        process.join()
+
+
+if __name__ == "__main__":
+    main()
--- a/synapse/appservice/scheduler.py
+++ b/synapse/appservice/scheduler.py
@ -319,7 +319,9 @@ class _ServiceQueuer:
        rooms_of_interesting_users.update(event.room_id for event in events)
        # EDUs
        rooms_of_interesting_users.update(
-            ephemeral["room_id"] for ephemeral in ephemerals
+            ephemeral["room_id"]
+            for ephemeral in ephemerals
+            if ephemeral.get("room_id") is not None
        )

        # Look up the AS users in those rooms
@ -329,8 +331,9 @@ class _ServiceQueuer:
            )

        # Add recipients of to-device messages.
-        # device_message["user_id"] is the ID of the recipient.
-        users.update(device_message["user_id"] for device_message in to_device_messages)
+        users.update(
+            device_message["to_user_id"] for device_message in to_device_messages
+        )

        # Compute and return the counts / fallback key usage states
        otk_counts = await self._store.count_bulk_e2e_one_time_keys_for_as(users)
--- a/synapse/config/cache.py
+++ b/synapse/config/cache.py
@ -21,7 +21,7 @@ from typing import Any, Callable, Dict, Optional
 import attr

 from synapse.types import JsonDict
-from synapse.util.check_dependencies import DependencyException, check_requirements
+from synapse.util.check_dependencies import check_requirements

 from ._base import Config, ConfigError

@ -159,12 +159,7 @@ class CacheConfig(Config):

        self.track_memory_usage = cache_config.get("track_memory_usage", False)
        if self.track_memory_usage:
-            try:
-                check_requirements("cache_memory")
-            except DependencyException as e:
-                raise ConfigError(
-                    e.message  # noqa: B306, DependencyException.message is a property
-                )
+            check_requirements("cache_memory")

        expire_caches = cache_config.get("expire_caches", True)
        cache_entry_ttl = cache_config.get("cache_entry_ttl", "30m")
--- a/synapse/config/emailconfig.py
+++ b/synapse/config/emailconfig.py
@ -145,7 +145,7 @@ class EmailConfig(Config):
            raise ConfigError(
                'The config option "trust_identity_server_for_password_resets" '
                'has been replaced by "account_threepid_delegate". '
-                "Please consult the sample config at docs/sample_config.yaml for "
+                "Please consult the configuration manual at docs/usage/configuration/config_documentation.md for "
                "details and update your config file."
            )

--- a/synapse/config/experimental.py
+++ b/synapse/config/experimental.py
@ -87,3 +87,6 @@ class ExperimentalConfig(Config):

        # MSC3715: dir param on /relations.
        self.msc3715_enabled: bool = experimental.get("msc3715_enabled", False)
+
+        # MSC3827: Filtering of /publicRooms by room type
+        self.msc3827_enabled: bool = experimental.get("msc3827_enabled", False)
--- a/synapse/config/jwt.py
+++ b/synapse/config/jwt.py
@ -15,14 +15,9 @@
 from typing import Any

 from synapse.types import JsonDict
+from synapse.util.check_dependencies import check_requirements

-from ._base import Config, ConfigError
-
-MISSING_AUTHLIB = """Missing authlib library. This is required for jwt login.
-
-    Install by running:
-        pip install synapse[jwt]
-    """
+from ._base import Config


 class JWTConfig(Config):
@ -41,13 +36,7 @@ class JWTConfig(Config):
            # that the claims exist on the JWT.
            self.jwt_issuer = jwt_config.get("issuer")
            self.jwt_audiences = jwt_config.get("audiences")
-
-            try:
-                from authlib.jose import JsonWebToken
-
-                JsonWebToken  # To stop unused lint.
-            except ImportError:
-                raise ConfigError(MISSING_AUTHLIB)
+            check_requirements("jwt")
        else:
            self.jwt_enabled = False
            self.jwt_secret = None
--- a/synapse/config/metrics.py
+++ b/synapse/config/metrics.py
@ -18,7 +18,7 @@ from typing import Any, Optional
 import attr

 from synapse.types import JsonDict
-from synapse.util.check_dependencies import DependencyException, check_requirements
+from synapse.util.check_dependencies import check_requirements

 from ._base import Config, ConfigError

@ -57,12 +57,7 @@ class MetricsConfig(Config):

        self.sentry_enabled = "sentry" in config
        if self.sentry_enabled:
-            try:
-                check_requirements("sentry")
-            except DependencyException as e:
-                raise ConfigError(
-                    e.message  # noqa: B306, DependencyException.message is a property
-                )
+            check_requirements("sentry")

            self.sentry_dsn = config["sentry"].get("dsn")
            if not self.sentry_dsn:
--- a/synapse/config/oidc.py
+++ b/synapse/config/oidc.py
@ -24,7 +24,7 @@ from synapse.types import JsonDict
 from synapse.util.module_loader import load_module
 from synapse.util.stringutils import parse_and_validate_mxc_uri

-from ..util.check_dependencies import DependencyException, check_requirements
+from ..util.check_dependencies import check_requirements
 from ._base import Config, ConfigError, read_file

 DEFAULT_USER_MAPPING_PROVIDER = "synapse.handlers.oidc.JinjaOidcMappingProvider"
@ -41,12 +41,7 @@ class OIDCConfig(Config):
        if not self.oidc_providers:
            return

-        try:
-            check_requirements("oidc")
-        except DependencyException as e:
-            raise ConfigError(
-                e.message  # noqa: B306, DependencyException.message is a property
-            ) from e
+        check_requirements("oidc")

        # check we don't have any duplicate idp_ids now. (The SSO handler will also
        # check for duplicates when the REST listeners get registered, but that happens
@ -146,7 +141,6 @@ OIDC_PROVIDER_CONFIG_WITH_ID_SCHEMA = {
    "allOf": [OIDC_PROVIDER_CONFIG_SCHEMA, {"required": ["idp_id", "idp_name"]}]
 }

-
 # the `oidc_providers` list can either be None (as it is in the default config), or
 # a list of provider configs, each of which requires an explicit ID and name.
 OIDC_PROVIDER_LIST_SCHEMA = {
--- a/synapse/config/ratelimiting.py
+++ b/synapse/config/ratelimiting.py
@ -136,6 +136,11 @@ class RatelimitConfig(Config):
            defaults={"per_second": 0.003, "burst_count": 5},
        )

+        self.rc_invites_per_issuer = RateLimitConfig(
+            config.get("rc_invites", {}).get("per_issuer", {}),
+            defaults={"per_second": 0.3, "burst_count": 10},
+        )
+
        self.rc_third_party_invite = RateLimitConfig(
            config.get("rc_third_party_invite", {}),
            defaults={
--- a/synapse/config/repository.py
+++ b/synapse/config/repository.py
@ -21,7 +21,7 @@ import attr

 from synapse.config.server import generate_ip_set
 from synapse.types import JsonDict
-from synapse.util.check_dependencies import DependencyException, check_requirements
+from synapse.util.check_dependencies import check_requirements
 from synapse.util.module_loader import load_module

 from ._base import Config, ConfigError
@ -185,13 +185,7 @@ class ContentRepositoryConfig(Config):
        )
        self.url_preview_enabled = config.get("url_preview_enabled", False)
        if self.url_preview_enabled:
-            try:
-                check_requirements("url_preview")
-
-            except DependencyException as e:
-                raise ConfigError(
-                    e.message  # noqa: B306, DependencyException.message is a property
-                )
+            check_requirements("url_preview")

            proxy_env = getproxies_environment()
            if "url_preview_ip_range_blacklist" not in config:
--- a/synapse/config/saml2.py
+++ b/synapse/config/saml2.py
@ -18,7 +18,7 @@ from typing import Any, List, Set

 from synapse.config.sso import SsoAttributeRequirement
 from synapse.types import JsonDict
-from synapse.util.check_dependencies import DependencyException, check_requirements
+from synapse.util.check_dependencies import check_requirements
 from synapse.util.module_loader import load_module, load_python_module

 from ._base import Config, ConfigError
@ -76,12 +76,7 @@ class SAML2Config(Config):
        if not saml2_config.get("sp_config") and not saml2_config.get("config_path"):
            return

-        try:
-            check_requirements("saml2")
-        except DependencyException as e:
-            raise ConfigError(
-                e.message  # noqa: B306, DependencyException.message is a property
-            )
+        check_requirements("saml2")

        self.saml2_enabled = True

--- a/synapse/config/tracer.py
+++ b/synapse/config/tracer.py
@ -15,7 +15,7 @@
 from typing import Any, List, Set

 from synapse.types import JsonDict
-from synapse.util.check_dependencies import DependencyException, check_requirements
+from synapse.util.check_dependencies import check_requirements

 from ._base import Config, ConfigError

@ -40,12 +40,7 @@ class TracerConfig(Config):
        if not self.opentracer_enabled:
            return

-        try:
-            check_requirements("opentracing")
-        except DependencyException as e:
-            raise ConfigError(
-                e.message  # noqa: B306, DependencyException.message is a property
-            )
+        check_requirements("opentracing")

        # The tracer is enabled so sanitize the config

--- a/synapse/events/spamcheck.py
+++ b/synapse/events/spamcheck.py
@ -21,7 +21,6 @@ from typing import (
    Awaitable,
    Callable,
    Collection,
-    Dict,
    List,
    Optional,
    Tuple,
@ -32,10 +31,11 @@ from typing import (
 from typing_extensions import Literal

 import synapse
+from synapse.api.errors import Codes
 from synapse.rest.media.v1._base import FileInfo
 from synapse.rest.media.v1.media_storage import ReadableFileWrapper
 from synapse.spam_checker_api import RegistrationBehaviour
-from synapse.types import RoomAlias, UserProfile
+from synapse.types import JsonDict, RoomAlias, UserProfile
 from synapse.util.async_helpers import delay_cancellation, maybe_awaitable
 from synapse.util.metrics import Measure

@ -50,12 +50,12 @@ CHECK_EVENT_FOR_SPAM_CALLBACK = Callable[
    Awaitable[
        Union[
            str,
-            "synapse.api.errors.Codes",
+            Codes,
            # Highly experimental, not officially part of the spamchecker API, may
            # disappear without warning depending on the results of ongoing
            # experiments.
            # Use this to return additional information as part of an error.
-            Tuple["synapse.api.errors.Codes", Dict],
+            Tuple[Codes, JsonDict],
            # Deprecated
            bool,
        ]
@ -70,7 +70,12 @@ USER_MAY_JOIN_ROOM_CALLBACK = Callable[
    Awaitable[
        Union[
            Literal["NOT_SPAM"],
-            "synapse.api.errors.Codes",
+            Codes,
+            # Highly experimental, not officially part of the spamchecker API, may
+            # disappear without warning depending on the results of ongoing
+            # experiments.
+            # Use this to return additional information as part of an error.
+            Tuple[Codes, JsonDict],
            # Deprecated
            bool,
        ]
@ -81,7 +86,12 @@ USER_MAY_INVITE_CALLBACK = Callable[
    Awaitable[
        Union[
            Literal["NOT_SPAM"],
-            "synapse.api.errors.Codes",
+            Codes,
+            # Highly experimental, not officially part of the spamchecker API, may
+            # disappear without warning depending on the results of ongoing
+            # experiments.
+            # Use this to return additional information as part of an error.
+            Tuple[Codes, JsonDict],
            # Deprecated
            bool,
        ]
@ -92,7 +102,12 @@ USER_MAY_SEND_3PID_INVITE_CALLBACK = Callable[
    Awaitable[
        Union[
            Literal["NOT_SPAM"],
-            "synapse.api.errors.Codes",
+            Codes,
+            # Highly experimental, not officially part of the spamchecker API, may
+            # disappear without warning depending on the results of ongoing
+            # experiments.
+            # Use this to return additional information as part of an error.
+            Tuple[Codes, JsonDict],
            # Deprecated
            bool,
        ]
@ -103,7 +118,12 @@ USER_MAY_CREATE_ROOM_CALLBACK = Callable[
    Awaitable[
        Union[
            Literal["NOT_SPAM"],
-            "synapse.api.errors.Codes",
+            Codes,
+            # Highly experimental, not officially part of the spamchecker API, may
+            # disappear without warning depending on the results of ongoing
+            # experiments.
+            # Use this to return additional information as part of an error.
+            Tuple[Codes, JsonDict],
            # Deprecated
            bool,
        ]
@ -114,7 +134,12 @@ USER_MAY_CREATE_ROOM_ALIAS_CALLBACK = Callable[
    Awaitable[
        Union[
            Literal["NOT_SPAM"],
-            "synapse.api.errors.Codes",
+            Codes,
+            # Highly experimental, not officially part of the spamchecker API, may
+            # disappear without warning depending on the results of ongoing
+            # experiments.
+            # Use this to return additional information as part of an error.
+            Tuple[Codes, JsonDict],
            # Deprecated
            bool,
        ]
@ -125,7 +150,12 @@ USER_MAY_PUBLISH_ROOM_CALLBACK = Callable[
    Awaitable[
        Union[
            Literal["NOT_SPAM"],
-            "synapse.api.errors.Codes",
+            Codes,
+            # Highly experimental, not officially part of the spamchecker API, may
+            # disappear without warning depending on the results of ongoing
+            # experiments.
+            # Use this to return additional information as part of an error.
+            Tuple[Codes, JsonDict],
            # Deprecated
            bool,
        ]
@ -154,7 +184,12 @@ CHECK_MEDIA_FILE_FOR_SPAM_CALLBACK = Callable[
    Awaitable[
        Union[
            Literal["NOT_SPAM"],
-            "synapse.api.errors.Codes",
+            Codes,
+            # Highly experimental, not officially part of the spamchecker API, may
+            # disappear without warning depending on the results of ongoing
+            # experiments.
+            # Use this to return additional information as part of an error.
+            Tuple[Codes, JsonDict],
            # Deprecated
            bool,
        ]
@ -345,7 +380,7 @@ class SpamChecker:

    async def check_event_for_spam(
        self, event: "synapse.events.EventBase"
-    ) -> Union[Tuple["synapse.api.errors.Codes", Dict], str]:
+    ) -> Union[Tuple[Codes, JsonDict], str]:
        """Checks if a given event is considered "spammy" by this server.

        If the server considers an event spammy, then it will be rejected if
@ -376,7 +411,16 @@ class SpamChecker:
                elif res is True:
                    # This spam-checker rejects the event with deprecated
                    # return value `True`
-                    return (synapse.api.errors.Codes.FORBIDDEN, {})
+                    return synapse.api.errors.Codes.FORBIDDEN, {}
+                elif (
+                    isinstance(res, tuple)
+                    and len(res) == 2
+                    and isinstance(res[0], synapse.api.errors.Codes)
+                    and isinstance(res[1], dict)
+                ):
+                    return res
+                elif isinstance(res, synapse.api.errors.Codes):
+                    return res, {}
                elif not isinstance(res, str):
                    # mypy complains that we can't reach this code because of the
                    # return type in CHECK_EVENT_FOR_SPAM_CALLBACK, but we don't know
@ -422,7 +466,7 @@ class SpamChecker:

    async def user_may_join_room(
        self, user_id: str, room_id: str, is_invited: bool
-    ) -> Union["synapse.api.errors.Codes", Literal["NOT_SPAM"]]:
+    ) -> Union[Tuple[Codes, JsonDict], Literal["NOT_SPAM"]]:
        """Checks if a given users is allowed to join a room.
        Not called when a user creates a room.

@ -432,7 +476,7 @@ class SpamChecker:
            is_invited: Whether the user is invited into the room

        Returns:
-            NOT_SPAM if the operation is permitted, Codes otherwise.
+            NOT_SPAM if the operation is permitted, [Codes, Dict] otherwise.
        """
        for callback in self._user_may_join_room_callbacks:
            with Measure(
@ -443,21 +487,28 @@ class SpamChecker:
                if res is True or res is self.NOT_SPAM:
                    continue
                elif res is False:
-                    return synapse.api.errors.Codes.FORBIDDEN
+                    return synapse.api.errors.Codes.FORBIDDEN, {}
                elif isinstance(res, synapse.api.errors.Codes):
+                    return res, {}
+                elif (
+                    isinstance(res, tuple)
+                    and len(res) == 2
+                    and isinstance(res[0], synapse.api.errors.Codes)
+                    and isinstance(res[1], dict)
+                ):
                    return res
                else:
                    logger.warning(
                        "Module returned invalid value, rejecting join as spam"
                    )
-                    return synapse.api.errors.Codes.FORBIDDEN
+                    return synapse.api.errors.Codes.FORBIDDEN, {}

        # No spam-checker has rejected the request, let it pass.
        return self.NOT_SPAM

    async def user_may_invite(
        self, inviter_userid: str, invitee_userid: str, room_id: str
-    ) -> Union["synapse.api.errors.Codes", Literal["NOT_SPAM"]]:
+    ) -> Union[Tuple[Codes, dict], Literal["NOT_SPAM"]]:
        """Checks if a given user may send an invite

        Args:
@ -479,21 +530,28 @@ class SpamChecker:
                if res is True or res is self.NOT_SPAM:
                    continue
                elif res is False:
-                    return synapse.api.errors.Codes.FORBIDDEN
+                    return synapse.api.errors.Codes.FORBIDDEN, {}
                elif isinstance(res, synapse.api.errors.Codes):
+                    return res, {}
+                elif (
+                    isinstance(res, tuple)
+                    and len(res) == 2
+                    and isinstance(res[0], synapse.api.errors.Codes)
+                    and isinstance(res[1], dict)
+                ):
                    return res
                else:
                    logger.warning(
                        "Module returned invalid value, rejecting invite as spam"
                    )
-                    return synapse.api.errors.Codes.FORBIDDEN
+                    return synapse.api.errors.Codes.FORBIDDEN, {}

        # No spam-checker has rejected the request, let it pass.
        return self.NOT_SPAM

    async def user_may_send_3pid_invite(
        self, inviter_userid: str, medium: str, address: str, room_id: str
-    ) -> Union["synapse.api.errors.Codes", Literal["NOT_SPAM"]]:
+    ) -> Union[Tuple[Codes, dict], Literal["NOT_SPAM"]]:
        """Checks if a given user may invite a given threepid into the room

        Note that if the threepid is already associated with a Matrix user ID, Synapse
@ -519,20 +577,27 @@ class SpamChecker:
                if res is True or res is self.NOT_SPAM:
                    continue
                elif res is False:
-                    return synapse.api.errors.Codes.FORBIDDEN
+                    return synapse.api.errors.Codes.FORBIDDEN, {}
                elif isinstance(res, synapse.api.errors.Codes):
+                    return res, {}
+                elif (
+                    isinstance(res, tuple)
+                    and len(res) == 2
+                    and isinstance(res[0], synapse.api.errors.Codes)
+                    and isinstance(res[1], dict)
+                ):
                    return res
                else:
                    logger.warning(
                        "Module returned invalid value, rejecting 3pid invite as spam"
                    )
-                    return synapse.api.errors.Codes.FORBIDDEN
+                    return synapse.api.errors.Codes.FORBIDDEN, {}

        return self.NOT_SPAM

    async def user_may_create_room(
        self, userid: str
-    ) -> Union["synapse.api.errors.Codes", Literal["NOT_SPAM"]]:
+    ) -> Union[Tuple[Codes, dict], Literal["NOT_SPAM"]]:
        """Checks if a given user may create a room

        Args:
@ -546,20 +611,27 @@ class SpamChecker:
                if res is True or res is self.NOT_SPAM:
                    continue
                elif res is False:
-                    return synapse.api.errors.Codes.FORBIDDEN
+                    return synapse.api.errors.Codes.FORBIDDEN, {}
                elif isinstance(res, synapse.api.errors.Codes):
+                    return res, {}
+                elif (
+                    isinstance(res, tuple)
+                    and len(res) == 2
+                    and isinstance(res[0], synapse.api.errors.Codes)
+                    and isinstance(res[1], dict)
+                ):
                    return res
                else:
                    logger.warning(
                        "Module returned invalid value, rejecting room creation as spam"
                    )
-                    return synapse.api.errors.Codes.FORBIDDEN
+                    return synapse.api.errors.Codes.FORBIDDEN, {}

        return self.NOT_SPAM

    async def user_may_create_room_alias(
        self, userid: str, room_alias: RoomAlias
-    ) -> Union["synapse.api.errors.Codes", Literal["NOT_SPAM"]]:
+    ) -> Union[Tuple[Codes, dict], Literal["NOT_SPAM"]]:
        """Checks if a given user may create a room alias

        Args:
@ -575,20 +647,27 @@ class SpamChecker:
                if res is True or res is self.NOT_SPAM:
                    continue
                elif res is False:
-                    return synapse.api.errors.Codes.FORBIDDEN
+                    return synapse.api.errors.Codes.FORBIDDEN, {}
                elif isinstance(res, synapse.api.errors.Codes):
+                    return res, {}
+                elif (
+                    isinstance(res, tuple)
+                    and len(res) == 2
+                    and isinstance(res[0], synapse.api.errors.Codes)
+                    and isinstance(res[1], dict)
+                ):
                    return res
                else:
                    logger.warning(
                        "Module returned invalid value, rejecting room create as spam"
                    )
-                    return synapse.api.errors.Codes.FORBIDDEN
+                    return synapse.api.errors.Codes.FORBIDDEN, {}

        return self.NOT_SPAM

    async def user_may_publish_room(
        self, userid: str, room_id: str
-    ) -> Union["synapse.api.errors.Codes", Literal["NOT_SPAM"]]:
+    ) -> Union[Tuple[Codes, dict], Literal["NOT_SPAM"]]:
        """Checks if a given user may publish a room to the directory

        Args:
@ -603,14 +682,21 @@ class SpamChecker:
                if res is True or res is self.NOT_SPAM:
                    continue
                elif res is False:
-                    return synapse.api.errors.Codes.FORBIDDEN
+                    return synapse.api.errors.Codes.FORBIDDEN, {}
                elif isinstance(res, synapse.api.errors.Codes):
+                    return res, {}
+                elif (
+                    isinstance(res, tuple)
+                    and len(res) == 2
+                    and isinstance(res[0], synapse.api.errors.Codes)
+                    and isinstance(res[1], dict)
+                ):
                    return res
                else:
                    logger.warning(
                        "Module returned invalid value, rejecting room publication as spam"
                    )
-                    return synapse.api.errors.Codes.FORBIDDEN
+                    return synapse.api.errors.Codes.FORBIDDEN, {}

        return self.NOT_SPAM

@ -678,7 +764,7 @@ class SpamChecker:

    async def check_media_file_for_spam(
        self, file_wrapper: ReadableFileWrapper, file_info: FileInfo
-    ) -> Union["synapse.api.errors.Codes", Literal["NOT_SPAM"]]:
+    ) -> Union[Tuple[Codes, dict], Literal["NOT_SPAM"]]:
        """Checks if a piece of newly uploaded media should be blocked.

        This will be called for local uploads, downloads of remote media, each
@ -715,13 +801,20 @@ class SpamChecker:
                if res is False or res is self.NOT_SPAM:
                    continue
                elif res is True:
-                    return synapse.api.errors.Codes.FORBIDDEN
+                    return synapse.api.errors.Codes.FORBIDDEN, {}
                elif isinstance(res, synapse.api.errors.Codes):
+                    return res, {}
+                elif (
+                    isinstance(res, tuple)
+                    and len(res) == 2
+                    and isinstance(res[0], synapse.api.errors.Codes)
+                    and isinstance(res[1], dict)
+                ):
                    return res
                else:
                    logger.warning(
                        "Module returned invalid value, rejecting media file as spam"
                    )
-                    return synapse.api.errors.Codes.FORBIDDEN
+                    return synapse.api.errors.Codes.FORBIDDEN, {}

        return self.NOT_SPAM
--- a/synapse/events/third_party_rules.py
+++ b/synapse/events/third_party_rules.py
@ -464,14 +464,7 @@ class ThirdPartyEventRules:
        Returns:
            A dict mapping (event type, state key) to state event.
        """
-        state_ids = await self._storage_controllers.state.get_current_state_ids(room_id)
-        room_state_events = await self.store.get_events(state_ids.values())
-
-        state_events = {}
-        for key, event_id in state_ids.items():
-            state_events[key] = room_state_events[event_id]
-
-        return state_events
+        return await self._storage_controllers.state.get_current_state(room_id)

    async def on_profile_update(
        self, user_id: str, new_profile: ProfileInfo, by_admin: bool, deactivation: bool
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@ -67,6 +67,7 @@ from synapse.replication.http.federation import (
    ReplicationFederationSendEduRestServlet,
    ReplicationGetQueryRestServlet,
 )
+from synapse.storage.databases.main.events import PartialStateConflictError
 from synapse.storage.databases.main.lock import Lock
 from synapse.types import JsonDict, StateMap, get_domain_from_id
 from synapse.util import json_decoder, unwrapFirstError
@ -882,9 +883,20 @@ class FederationServer(FederationBase):
            logger.warning("%s", errmsg)
            raise SynapseError(403, errmsg, Codes.FORBIDDEN)

-        return await self._federation_event_handler.on_send_membership_event(
-            origin, event
-        )
+        try:
+            return await self._federation_event_handler.on_send_membership_event(
+                origin, event
+            )
+        except PartialStateConflictError:
+            # The room was un-partial stated while we were persisting the event.
+            # Try once more, with full state this time.
+            logger.info(
+                "Room %s was un-partial stated during `on_send_membership_event`, trying again.",
+                room_id,
+            )
+            return await self._federation_event_handler.on_send_membership_event(
+                origin, event
+            )

    async def on_event_auth(
        self, origin: str, room_id: str, event_id: str
--- a/synapse/handlers/directory.py
+++ b/synapse/handlers/directory.py
@ -151,7 +151,8 @@ class DirectoryHandler:
                raise AuthError(
                    403,
                    "This user is not permitted to create this alias",
-                    spam_check,
+                    errcode=spam_check[0],
+                    additional_fields=spam_check[1],
                )

            if not self.config.roomdirectory.is_alias_creation_allowed(
@ -443,7 +444,8 @@ class DirectoryHandler:
            raise AuthError(
                403,
                "This user is not permitted to publish rooms to the room list",
-                spam_check,
+                errcode=spam_check[0],
+                additional_fields=spam_check[1],
            )

        if requester.is_guest:
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@ -45,6 +45,7 @@ from synapse.api.errors import (
    FederationDeniedError,
    FederationError,
    HttpResponseException,
+    LimitExceededError,
    NotFoundError,
    RequestSendFailed,
    SynapseError,
@ -64,6 +65,7 @@ from synapse.replication.http.federation import (
    ReplicationCleanRoomRestServlet,
    ReplicationStoreRoomOnOutlierMembershipRestServlet,
 )
+from synapse.storage.databases.main.events import PartialStateConflictError
 from synapse.storage.databases.main.events_worker import EventRedactBehaviour
 from synapse.storage.state import StateFilter
 from synapse.types import JsonDict, StateMap, get_domain_from_id
@ -549,15 +551,29 @@ class FederationHandler:
                #   https://github.com/matrix-org/synapse/issues/12998
                await self.store.store_partial_state_room(room_id, ret.servers_in_room)

-            max_stream_id = await self._federation_event_handler.process_remote_join(
-                origin,
-                room_id,
-                auth_chain,
-                state,
-                event,
-                room_version_obj,
-                partial_state=ret.partial_state,
-            )
+            try:
+                max_stream_id = (
+                    await self._federation_event_handler.process_remote_join(
+                        origin,
+                        room_id,
+                        auth_chain,
+                        state,
+                        event,
+                        room_version_obj,
+                        partial_state=ret.partial_state,
+                    )
+                )
+            except PartialStateConflictError as e:
+                # The homeserver was already in the room and it is no longer partial
+                # stated. We ought to be doing a local join instead. Turn the error into
+                # a 429, as a hint to the client to try again.
+                # TODO(faster_joins): `_should_perform_remote_join` suggests that we may
+                #   do a remote join for restricted rooms even if we have full state.
+                logger.error(
+                    "Room %s was un-partial stated while processing remote join.",
+                    room_id,
+                )
+                raise LimitExceededError(msg=e.msg, errcode=e.errcode, retry_after_ms=0)

            if ret.partial_state:
                # Kick off the process of asynchronously fetching the state for this
@ -828,7 +844,8 @@ class FederationHandler:
            raise SynapseError(
                403,
                "This user is not permitted to send invites to this server/user",
-                spam_check,
+                errcode=spam_check[0],
+                additional_fields=spam_check[1],
            )

        membership = event.content.get("membership")
@ -1543,14 +1560,9 @@ class FederationHandler:
                # all the events are updated, so we can update current state and
                # clear the lazy-loading flag.
                logger.info("Updating current state for %s", room_id)
-                # TODO(faster_joins): support workers
+                # TODO(faster_joins): notify workers in notify_room_un_partial_stated
                #   https://github.com/matrix-org/synapse/issues/12994
-                assert (
-                    self._storage_controllers.persistence is not None
-                ), "worker-mode deployments not currently supported here"
-                await self._storage_controllers.persistence.update_current_state(
-                    room_id
-                )
+                await self.state_handler.update_current_state(room_id)

                logger.info("Clearing partial-state flag for %s", room_id)
                success = await self.store.clear_partial_state_room(room_id)
@ -1567,11 +1579,6 @@ class FederationHandler:

                # we raced against more events arriving with partial state. Go round
                # the loop again. We've already logged a warning, so no need for more.
-                # TODO(faster_joins): there is still a race here, whereby incoming events which raced
-                #   with us will fail to be persisted after the call to `clear_partial_state_room` due to
-                #   having partial state.
-                #   https://github.com/matrix-org/synapse/issues/12988
-                #
                continue

            events = await self.store.get_events_as_list(
--- a/synapse/handlers/federation_event.py
+++ b/synapse/handlers/federation_event.py
@ -64,6 +64,7 @@ from synapse.replication.http.federation import (
    ReplicationFederationSendEventsRestServlet,
 )
 from synapse.state import StateResolutionStore
+from synapse.storage.databases.main.events import PartialStateConflictError
 from synapse.storage.databases.main.events_worker import EventRedactBehaviour
 from synapse.storage.state import StateFilter
 from synapse.types import (
@ -275,7 +276,16 @@ class FederationEventHandler:
                    affected=pdu.event_id,
                )

-        await self._process_received_pdu(origin, pdu, state_ids=None)
+        try:
+            await self._process_received_pdu(origin, pdu, state_ids=None)
+        except PartialStateConflictError:
+            # The room was un-partial stated while we were processing the PDU.
+            # Try once more, with full state this time.
+            logger.info(
+                "Room %s was un-partial stated while processing the PDU, trying again.",
+                room_id,
+            )
+            await self._process_received_pdu(origin, pdu, state_ids=None)

    async def on_send_membership_event(
        self, origin: str, event: EventBase
@ -306,6 +316,9 @@ class FederationEventHandler:

        Raises:
            SynapseError if the event is not accepted into the room
+            PartialStateConflictError if the room was un-partial stated in between
+                computing the state at the event and persisting it. The caller should
+                retry exactly once in this case.
        """
        logger.debug(
            "on_send_membership_event: Got event: %s, signatures: %s",
@ -423,6 +436,8 @@ class FederationEventHandler:

        Raises:
            SynapseError if the response is in some way invalid.
+            PartialStateConflictError if the homeserver is already in the room and it
+                has been un-partial stated.
        """
        create_event = None
        for e in state:
@ -1084,28 +1099,31 @@ class FederationEventHandler:

            state_ids: Normally None, but if we are handling a gap in the graph
                (ie, we are missing one or more prev_events), the resolved state at the
-                event
+                event. Must not be partial state.

            backfilled: True if this is part of a historical batch of events (inhibits
                notification to clients, and validation of device keys.)
+
+        PartialStateConflictError: if the room was un-partial stated in between
+            computing the state at the event and persisting it. The caller should retry
+            exactly once in this case. Will never be raised if `state_ids` is provided.
        """
        logger.debug("Processing event: %s", event)
        assert not event.internal_metadata.outlier

+        context = await self._state_handler.compute_event_context(
+            event,
+            state_ids_before_event=state_ids,
+        )
        try:
-            context = await self._state_handler.compute_event_context(
-                event,
-                state_ids_before_event=state_ids,
-            )
            context = await self._check_event_auth(
                origin,
                event,
                context,
            )
        except AuthError as e:
-            # FIXME richvdh 2021/10/07 I don't think this is reachable. Let's log it
-            #   for now
-            logger.exception("Unexpected AuthError from _check_event_auth")
+            # This happens only if we couldn't find the auth events. We'll already have
+            # logged a warning, so now we just convert to a FederationError.
            raise FederationError("ERROR", e.code, e.msg, affected=event.event_id)

        if not backfilled and not context.rejected:
@ -1934,6 +1952,9 @@ class FederationEventHandler:
            event: The event itself.
            context: The event context.
            backfilled: True if the event was backfilled.
+
+        PartialStateConflictError: if attempting to persist a partial state event in
+            a room that has been un-partial stated.
        """
        # this method should not be called on outliers (those code paths call
        # persist_events_and_notify directly.)
@ -1986,6 +2007,10 @@ class FederationEventHandler:

        Returns:
            The stream ID after which all events have been persisted.
+
+        Raises:
+            PartialStateConflictError: if attempting to persist a partial state event in
+                a room that has been un-partial stated.
        """
        if not event_and_contexts:
            return self._store.get_room_max_stream_ordering()
@ -1994,14 +2019,19 @@ class FederationEventHandler:
        if instance != self._instance_name:
            # Limit the number of events sent over replication. We choose 200
            # here as that is what we default to in `max_request_body_size(..)`
-            for batch in batch_iter(event_and_contexts, 200):
-                result = await self._send_events(
-                    instance_name=instance,
-                    store=self._store,
-                    room_id=room_id,
-                    event_and_contexts=batch,
-                    backfilled=backfilled,
-                )
+            try:
+                for batch in batch_iter(event_and_contexts, 200):
+                    result = await self._send_events(
+                        instance_name=instance,
+                        store=self._store,
+                        room_id=room_id,
+                        event_and_contexts=batch,
+                        backfilled=backfilled,
+                    )
+            except SynapseError as e:
+                if e.code == HTTPStatus.CONFLICT:
+                    raise PartialStateConflictError()
+                raise
            return result["max_stream_id"]
        else:
            assert self._storage_controllers.persistence
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@ -37,6 +37,7 @@ from synapse.api.errors import (
    AuthError,
    Codes,
    ConsentNotGivenError,
+    LimitExceededError,
    NotFoundError,
    ShadowBanError,
    SynapseError,
@ -53,6 +54,7 @@ from synapse.handlers.directory import DirectoryHandler
 from synapse.logging.context import make_deferred_yieldable, run_in_background
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.replication.http.send_event import ReplicationSendEventRestServlet
+from synapse.storage.databases.main.events import PartialStateConflictError
 from synapse.storage.databases.main.events_worker import EventRedactBehaviour
 from synapse.storage.state import StateFilter
 from synapse.types import (
@ -905,6 +907,9 @@ class EventCreationHandler:
            await self.clock.sleep(random.randint(1, 10))
            raise ShadowBanError()

+        if ratelimit:
+            await self.request_ratelimiter.ratelimit(requester, update=False)
+
        # We limit the number of concurrent event sends in a room so that we
        # don't fork the DAG too much. If we don't limit then we can end up in
        # a situation where event persistence can't keep up, causing
@ -1252,6 +1257,8 @@ class EventCreationHandler:

        Raises:
            ShadowBanError if the requester has been shadow-banned.
+            SynapseError(503) if attempting to persist a partial state event in
+                a room that has been un-partial stated.
        """
        extra_users = extra_users or []

@ -1302,25 +1309,36 @@ class EventCreationHandler:

        # We now persist the event (and update the cache in parallel, since we
        # don't want to block on it).
-        result, _ = await make_deferred_yieldable(
-            gather_results(
-                (
-                    run_in_background(
-                        self._persist_event,
-                        requester=requester,
-                        event=event,
-                        context=context,
-                        ratelimit=ratelimit,
-                        extra_users=extra_users,
-                        dont_notify=dont_notify,
+        try:
+            result, _ = await make_deferred_yieldable(
+                gather_results(
+                    (
+                        run_in_background(
+                            self._persist_event,
+                            requester=requester,
+                            event=event,
+                            context=context,
+                            ratelimit=ratelimit,
+                            extra_users=extra_users,
+                            dont_notify=dont_notify,
+                        ),
+                        run_in_background(
+                            self.cache_joined_hosts_for_event, event, context
+                        ).addErrback(
+                            log_failure, "cache_joined_hosts_for_event failed"
+                        ),
                    ),
-                    run_in_background(
-                        self.cache_joined_hosts_for_event, event, context
-                    ).addErrback(log_failure, "cache_joined_hosts_for_event failed"),
-                ),
-                consumeErrors=True,
+                    consumeErrors=True,
+                )
+            ).addErrback(unwrapFirstError)
+        except PartialStateConflictError as e:
+            # The event context needs to be recomputed.
+            # Turn the error into a 429, as a hint to the client to try again.
+            logger.info(
+                "Room %s was un-partial stated while persisting client event.",
+                event.room_id,
            )
-        ).addErrback(unwrapFirstError)
+            raise LimitExceededError(msg=e.msg, errcode=e.errcode, retry_after_ms=0)

        return result

@ -1336,6 +1354,9 @@ class EventCreationHandler:
        """Actually persists the event. Should only be called by
        `handle_new_client_event`, and see its docstring for documentation of
        the arguments.
+
+        PartialStateConflictError: if attempting to persist a partial state event in
+            a room that has been un-partial stated.
        """

        # Skip push notification actions for historical messages
@ -1352,17 +1373,22 @@ class EventCreationHandler:
            # If we're a worker we need to hit out to the master.
            writer_instance = self._events_shard_config.get_instance(event.room_id)
            if writer_instance != self._instance_name:
-                result = await self.send_event(
-                    instance_name=writer_instance,
-                    event_id=event.event_id,
-                    store=self.store,
-                    requester=requester,
-                    event=event,
-                    context=context,
-                    ratelimit=ratelimit,
-                    extra_users=extra_users,
-                    dont_notify=dont_notify,
-                )
+                try:
+                    result = await self.send_event(
+                        instance_name=writer_instance,
+                        event_id=event.event_id,
+                        store=self.store,
+                        requester=requester,
+                        event=event,
+                        context=context,
+                        ratelimit=ratelimit,
+                        extra_users=extra_users,
+                        dont_notify=dont_notify,
+                    )
+                except SynapseError as e:
+                    if e.code == HTTPStatus.CONFLICT:
+                        raise PartialStateConflictError()
+                    raise
                stream_id = result["stream_id"]
                event_id = result["event_id"]
                if event_id != event.event_id:
@ -1491,6 +1517,10 @@ class EventCreationHandler:
            The persisted event. This may be different than the given event if
            it was de-duplicated (e.g. because we had already persisted an
            event with the same transaction ID.)
+
+        Raises:
+            PartialStateConflictError: if attempting to persist a partial state event in
+                a room that has been un-partial stated.
        """
        extra_users = extra_users or []

--- a/synapse/handlers/profile.py
+++ b/synapse/handlers/profile.py
@ -67,19 +67,14 @@ class ProfileHandler:
        target_user = UserID.from_string(user_id)

        if self.hs.is_mine(target_user):
-            try:
-                displayname = await self.store.get_profile_displayname(
-                    target_user.localpart
-                )
-                avatar_url = await self.store.get_profile_avatar_url(
-                    target_user.localpart
-                )
-            except StoreError as e:
-                if e.code == 404:
-                    raise SynapseError(404, "Profile was not found", Codes.NOT_FOUND)
-                raise
+            profileinfo = await self.store.get_profileinfo(target_user.localpart)
+            if profileinfo.display_name is None:
+                raise SynapseError(404, "Profile was not found", Codes.NOT_FOUND)

-            return {"displayname": displayname, "avatar_url": avatar_url}
+            return {
+                "displayname": profileinfo.display_name,
+                "avatar_url": profileinfo.avatar_url,
+            }
        else:
            try:
                result = await self.federation.make_query(
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@ -440,7 +440,12 @@ class RoomCreationHandler:

        spam_check = await self.spam_checker.user_may_create_room(user_id)
        if spam_check != NOT_SPAM:
-            raise SynapseError(403, "You are not permitted to create rooms", spam_check)
+            raise SynapseError(
+                403,
+                "You are not permitted to create rooms",
+                errcode=spam_check[0],
+                additional_fields=spam_check[1],
+            )

        creation_content: JsonDict = {
            "room_version": new_room_version.identifier,
@ -731,7 +736,10 @@ class RoomCreationHandler:
            spam_check = await self.spam_checker.user_may_create_room(user_id)
            if spam_check != NOT_SPAM:
                raise SynapseError(
-                    403, "You are not permitted to create rooms", spam_check
+                    403,
+                    "You are not permitted to create rooms",
+                    errcode=spam_check[0],
+                    additional_fields=spam_check[1],
                )

        if ratelimit:
@ -1023,6 +1031,8 @@ class RoomCreationHandler:

        event_keys = {"room_id": room_id, "sender": creator_id, "state_key": ""}

+        last_sent_event_id: Optional[str] = None
+
        def create(etype: str, content: JsonDict, **kwargs: Any) -> JsonDict:
            e = {"type": etype, "content": content}

@ -1032,19 +1042,27 @@ class RoomCreationHandler:
            return e

        async def send(etype: str, content: JsonDict, **kwargs: Any) -> int:
+            nonlocal last_sent_event_id
+
            event = create(etype, content, **kwargs)
            logger.debug("Sending %s in new room", etype)
            # Allow these events to be sent even if the user is shadow-banned to
            # allow the room creation to complete.
            (
-                _,
+                sent_event,
                last_stream_id,
            ) = await self.event_creation_handler.create_and_send_nonmember_event(
                creator,
                event,
                ratelimit=False,
                ignore_shadow_ban=True,
+                # Note: we don't pass state_event_ids here because this triggers
+                # an additional query per event to look them up from the events table.
+                prev_event_ids=[last_sent_event_id] if last_sent_event_id else [],
            )
+
+            last_sent_event_id = sent_event.event_id
+
            return last_stream_id

        try:
@ -1058,7 +1076,9 @@ class RoomCreationHandler:
        await send(etype=EventTypes.Create, content=creation_content)

        logger.debug("Sending %s in new room", EventTypes.Member)
-        await self.room_member_handler.update_membership(
+        # Room create event must exist at this point
+        assert last_sent_event_id is not None
+        member_event_id, _ = await self.room_member_handler.update_membership(
            creator,
            creator.user,
            room_id,
@ -1066,7 +1086,9 @@ class RoomCreationHandler:
            ratelimit=ratelimit,
            content=creator_join_profile,
            new_room=True,
+            prev_event_ids=[last_sent_event_id],
        )
+        last_sent_event_id = member_event_id

        # We treat the power levels override specially as this needs to be one
        # of the first events that get sent into a room.
@ -1387,6 +1409,7 @@ class TimestampLookupHandler:
        # the timestamp given and the event we were able to find locally
        is_event_next_to_backward_gap = False
        is_event_next_to_forward_gap = False
+        local_event = None
        if local_event_id:
            local_event = await self.store.get_event(
                local_event_id, allow_none=False, allow_rejected=False
@ -1473,7 +1496,10 @@ class TimestampLookupHandler:
                        ex.args,
                    )

-        if not local_event_id:
+        # To appease mypy, we have to add both of these conditions to check for
+        # `None`. We only expect `local_event` to be `None` when
+        # `local_event_id` is `None` but mypy isn't as smart and assuming as us.
+        if not local_event_id or not local_event:
            raise SynapseError(
                404,
                "Unable to find event from %s in direction %s" % (timestamp, direction),
--- a/synapse/handlers/room_list.py
+++ b/synapse/handlers/room_list.py
@ -25,6 +25,7 @@ from synapse.api.constants import (
    GuestAccess,
    HistoryVisibility,
    JoinRules,
+    PublicRoomsFilterFields,
 )
 from synapse.api.errors import (
    Codes,
@ -181,6 +182,7 @@ class RoomListHandler:
                == HistoryVisibility.WORLD_READABLE,
                "guest_can_join": room["guest_access"] == "can_join",
                "join_rule": room["join_rules"],
+                "org.matrix.msc3827.room_type": room["room_type"],
            }

            # Filter out Nones – rather omit the field altogether
@ -239,7 +241,9 @@ class RoomListHandler:
        response["chunk"] = results

        response["total_room_count_estimate"] = await self.store.count_public_rooms(
-            network_tuple, ignore_non_federatable=from_federation
+            network_tuple,
+            ignore_non_federatable=from_federation,
+            search_filter=search_filter,
        )

        return response
@ -508,8 +512,21 @@ class RoomListNextBatch:


 def _matches_room_entry(room_entry: JsonDict, search_filter: dict) -> bool:
-    if search_filter and search_filter.get("generic_search_term", None):
-        generic_search_term = search_filter["generic_search_term"].upper()
+    """Determines whether the given search filter matches a room entry returned over
+    federation.
+
+    Only used if the remote server does not support MSC2197 remote-filtered search, and
+    hence does not support MSC3827 filtering of `/publicRooms` by room type either.
+
+    In this case, we cannot apply the `room_type` filter since no `room_type` field is
+    returned.
+    """
+    if search_filter and search_filter.get(
+        PublicRoomsFilterFields.GENERIC_SEARCH_TERM, None
+    ):
+        generic_search_term = search_filter[
+            PublicRoomsFilterFields.GENERIC_SEARCH_TERM
+        ].upper()
        if generic_search_term in room_entry.get("name", "").upper():
            return True
        elif generic_search_term in room_entry.get("topic", "").upper():
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@ -101,19 +101,33 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
            burst_count=hs.config.ratelimiting.rc_joins_remote.burst_count,
        )

+        # Ratelimiter for invites, keyed by room (across all issuers, all
+        # recipients).
        self._invites_per_room_limiter = Ratelimiter(
            store=self.store,
            clock=self.clock,
            rate_hz=hs.config.ratelimiting.rc_invites_per_room.per_second,
            burst_count=hs.config.ratelimiting.rc_invites_per_room.burst_count,
        )
-        self._invites_per_user_limiter = Ratelimiter(
+
+        # Ratelimiter for invites, keyed by recipient (across all rooms, all
+        # issuers).
+        self._invites_per_recipient_limiter = Ratelimiter(
            store=self.store,
            clock=self.clock,
            rate_hz=hs.config.ratelimiting.rc_invites_per_user.per_second,
            burst_count=hs.config.ratelimiting.rc_invites_per_user.burst_count,
        )

+        # Ratelimiter for invites, keyed by issuer (across all rooms, all
+        # recipients).
+        self._invites_per_issuer_limiter = Ratelimiter(
+            store=self.store,
+            clock=self.clock,
+            rate_hz=hs.config.ratelimiting.rc_invites_per_issuer.per_second,
+            burst_count=hs.config.ratelimiting.rc_invites_per_issuer.burst_count,
+        )
+
        self._third_party_invite_limiter = Ratelimiter(
            store=self.store,
            clock=self.clock,
@ -258,7 +272,9 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
        if room_id:
            await self._invites_per_room_limiter.ratelimit(requester, room_id)

-        await self._invites_per_user_limiter.ratelimit(requester, invitee_user_id)
+        await self._invites_per_recipient_limiter.ratelimit(requester, invitee_user_id)
+        if requester is not None:
+            await self._invites_per_issuer_limiter.ratelimit(requester)

    async def _local_membership_update(
        self,
@ -669,7 +685,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
            if target_id == self._server_notices_mxid:
                raise SynapseError(HTTPStatus.FORBIDDEN, "Cannot invite this user")

-            block_invite_code = None
+            block_invite_result = None

            if (
                self._server_notices_mxid is not None
@ -687,18 +703,21 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
                        "Blocking invite: user is not admin and non-admin "
                        "invites disabled"
                    )
-                    block_invite_code = Codes.FORBIDDEN
+                    block_invite_result = (Codes.FORBIDDEN, {})

                spam_check = await self.spam_checker.user_may_invite(
                    requester.user.to_string(), target_id, room_id
                )
                if spam_check != NOT_SPAM:
                    logger.info("Blocking invite due to spam checker")
-                    block_invite_code = spam_check
+                    block_invite_result = spam_check

-            if block_invite_code is not None:
+            if block_invite_result is not None:
                raise SynapseError(
-                    403, "Invites have been disabled on this server", block_invite_code
+                    403,
+                    "Invites have been disabled on this server",
+                    errcode=block_invite_result[0],
+                    additional_fields=block_invite_result[1],
                )

        # An empty prev_events list is allowed as long as the auth_event_ids are present
@ -812,7 +831,12 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
                    target.to_string(), room_id, is_invited=inviter is not None
                )
                if spam_check != NOT_SPAM:
-                    raise SynapseError(403, "Not allowed to join this room", spam_check)
+                    raise SynapseError(
+                        403,
+                        "Not allowed to join this room",
+                        errcode=spam_check[0],
+                        additional_fields=spam_check[1],
+                    )

            # Check if a remote join should be performed.
            remote_join, remote_room_hosts = await self._should_perform_remote_join(
@ -830,10 +854,17 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):

                content["membership"] = Membership.JOIN

-                profile = self.profile_handler
-                if not content_specified:
-                    content["displayname"] = await profile.get_displayname(target)
-                    content["avatar_url"] = await profile.get_avatar_url(target)
+                try:
+                    profile = self.profile_handler
+                    if not content_specified:
+                        content["displayname"] = await profile.get_displayname(target)
+                        content["avatar_url"] = await profile.get_avatar_url(target)
+                except Exception as e:
+                    logger.info(
+                        "Failed to get profile information while processing remote join for %r: %s",
+                        target,
+                        e,
+                    )

                if requester.is_guest:
                    content["kind"] = "guest"
@ -910,11 +941,18 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):

                content["membership"] = Membership.KNOCK

-                profile = self.profile_handler
-                if "displayname" not in content:
-                    content["displayname"] = await profile.get_displayname(target)
-                if "avatar_url" not in content:
-                    content["avatar_url"] = await profile.get_avatar_url(target)
+                try:
+                    profile = self.profile_handler
+                    if "displayname" not in content:
+                        content["displayname"] = await profile.get_displayname(target)
+                    if "avatar_url" not in content:
+                        content["avatar_url"] = await profile.get_avatar_url(target)
+                except Exception as e:
+                    logger.info(
+                        "Failed to get profile information while processing remote knock for %r: %s",
+                        target,
+                        e,
+                    )

                return await self.remote_knock(
                    remote_room_hosts, room_id, target, content
@ -1357,7 +1395,12 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
                room_id=room_id,
            )
            if spam_check != NOT_SPAM:
-                raise SynapseError(403, "Cannot send threepid invite", spam_check)
+                raise SynapseError(
+                    403,
+                    "Cannot send threepid invite",
+                    errcode=spam_check[0],
+                    additional_fields=spam_check[1],
+                )

            stream_id = await self._make_and_store_3pid_invite(
                requester,
--- a/synapse/handlers/stats.py
+++ b/synapse/handlers/stats.py
@ -271,6 +271,9 @@ class StatsHandler:
                room_state["is_federatable"] = (
                    event_content.get(EventContentFields.FEDERATE, True) is True
                )
+                room_type = event_content.get(EventContentFields.ROOM_TYPE)
+                if isinstance(room_type, str):
+                    room_state["room_type"] = room_type
            elif typ == EventTypes.JoinRules:
                room_state["join_rules"] = event_content.get("join_rule")
            elif typ == EventTypes.RoomHistoryVisibility:
--- a/synapse/logging/opentracing.py
+++ b/synapse/logging/opentracing.py
@ -164,6 +164,7 @@ Gotchas
  with an active span?
 """
 import contextlib
+import enum
 import inspect
 import logging
 import re
@ -268,7 +269,7 @@ try:

        _reporter: Reporter = attr.Factory(Reporter)

-        def set_process(self, *args, **kwargs):
+        def set_process(self, *args: Any, **kwargs: Any) -> None:
            return self._reporter.set_process(*args, **kwargs)

        def report_span(self, span: "opentracing.Span") -> None:
@ -319,7 +320,11 @@ _homeserver_whitelist: Optional[Pattern[str]] = None

 # Util methods

-Sentinel = object()
+
+class _Sentinel(enum.Enum):
+    # defining a sentinel in this way allows mypy to correctly handle the
+    # type of a dictionary lookup.
+    sentinel = object()


 P = ParamSpec("P")
@ -339,12 +344,12 @@ def only_if_tracing(func: Callable[P, R]) -> Callable[P, Optional[R]]:
    return _only_if_tracing_inner


-def ensure_active_span(message, ret=None):
+def ensure_active_span(message: str, ret=None):
    """Executes the operation only if opentracing is enabled and there is an active span.
    If there is no active span it logs message at the error level.

    Args:
-        message (str): Message which fills in "There was no active span when trying to %s"
+        message: Message which fills in "There was no active span when trying to %s"
            in the error log if there is no active span and opentracing is enabled.
        ret (object): return value if opentracing is None or there is no active span.

@ -402,7 +407,7 @@ def init_tracer(hs: "HomeServer") -> None:
    config = JaegerConfig(
        config=hs.config.tracing.jaeger_config,
        service_name=f"{hs.config.server.server_name} {hs.get_instance_name()}",
-        scope_manager=LogContextScopeManager(hs.config),
+        scope_manager=LogContextScopeManager(),
        metrics_factory=PrometheusMetricsFactory(),
    )

@ -451,15 +456,15 @@ def whitelisted_homeserver(destination: str) -> bool:

 # Could use kwargs but I want these to be explicit
 def start_active_span(
-    operation_name,
-    child_of=None,
-    references=None,
-    tags=None,
-    start_time=None,
-    ignore_active_span=False,
-    finish_on_close=True,
+    operation_name: str,
+    child_of: Optional[Union["opentracing.Span", "opentracing.SpanContext"]] = None,
+    references: Optional[List["opentracing.Reference"]] = None,
+    tags: Optional[Dict[str, str]] = None,
+    start_time: Optional[float] = None,
+    ignore_active_span: bool = False,
+    finish_on_close: bool = True,
    *,
-    tracer=None,
+    tracer: Optional["opentracing.Tracer"] = None,
 ):
    """Starts an active opentracing span.

@ -493,11 +498,11 @@ def start_active_span(
 def start_active_span_follows_from(
    operation_name: str,
    contexts: Collection,
-    child_of=None,
+    child_of: Optional[Union["opentracing.Span", "opentracing.SpanContext"]] = None,
    start_time: Optional[float] = None,
    *,
-    inherit_force_tracing=False,
-    tracer=None,
+    inherit_force_tracing: bool = False,
+    tracer: Optional["opentracing.Tracer"] = None,
 ):
    """Starts an active opentracing span, with additional references to previous spans

@ -540,7 +545,7 @@ def start_active_span_from_edu(
    edu_content: Dict[str, Any],
    operation_name: str,
    references: Optional[List["opentracing.Reference"]] = None,
-    tags: Optional[Dict] = None,
+    tags: Optional[Dict[str, str]] = None,
    start_time: Optional[float] = None,
    ignore_active_span: bool = False,
    finish_on_close: bool = True,
@ -617,23 +622,27 @@ def set_operation_name(operation_name: str) -> None:


@only_if_tracing
-def force_tracing(span=Sentinel) -> None:
+def force_tracing(
+    span: Union["opentracing.Span", _Sentinel] = _Sentinel.sentinel
+) -> None:
    """Force sampling for the active/given span and its children.

    Args:
        span: span to force tracing for. By default, the active span.
    """
-    if span is Sentinel:
-        span = opentracing.tracer.active_span
-    if span is None:
+    if isinstance(span, _Sentinel):
+        span_to_trace = opentracing.tracer.active_span
+    else:
+        span_to_trace = span
+    if span_to_trace is None:
        logger.error("No active span in force_tracing")
        return

-    span.set_tag(opentracing.tags.SAMPLING_PRIORITY, 1)
+    span_to_trace.set_tag(opentracing.tags.SAMPLING_PRIORITY, 1)

    # also set a bit of baggage, so that we have a way of figuring out if
    # it is enabled later
-    span.set_baggage_item(SynapseBaggage.FORCE_TRACING, "1")
+    span_to_trace.set_baggage_item(SynapseBaggage.FORCE_TRACING, "1")


 def is_context_forced_tracing(
@ -789,7 +798,7 @@ def extract_text_map(carrier: Dict[str, str]) -> Optional["opentracing.SpanConte
 # Tracing decorators


-def trace(func=None, opname=None):
+def trace(func=None, opname: Optional[str] = None):
    """
    Decorator to trace a function.
    Sets the operation name to that of the function's or that given
@ -822,11 +831,11 @@ def trace(func=None, opname=None):
                    result = func(*args, **kwargs)
                    if isinstance(result, defer.Deferred):

-                        def call_back(result):
+                        def call_back(result: R) -> R:
                            scope.__exit__(None, None, None)
                            return result

-                        def err_back(result):
+                        def err_back(result: R) -> R:
                            scope.__exit__(None, None, None)
                            return result

--- a/synapse/logging/scopecontextmanager.py
+++ b/synapse/logging/scopecontextmanager.py
@ -16,11 +16,15 @@ import logging
 from types import TracebackType
 from typing import Optional, Type

-from opentracing import Scope, ScopeManager
+from opentracing import Scope, ScopeManager, Span

 import twisted

-from synapse.logging.context import current_context, nested_logging_context
+from synapse.logging.context import (
+    LoggingContext,
+    current_context,
+    nested_logging_context,
+)

 logger = logging.getLogger(__name__)

@ -35,11 +39,11 @@ class LogContextScopeManager(ScopeManager):
    but currently that doesn't work due to https://twistedmatrix.com/trac/ticket/10301.
    """

-    def __init__(self, config):
+    def __init__(self) -> None:
        pass

    @property
-    def active(self):
+    def active(self) -> Optional[Scope]:
        """
        Returns the currently active Scope which can be used to access the
        currently active Scope.span.
@ -48,19 +52,18 @@ class LogContextScopeManager(ScopeManager):
        Tracer.start_active_span() time.

        Return:
-            (Scope) : the Scope that is active, or None if not
-            available.
+            The Scope that is active, or None if not available.
        """
        ctx = current_context()
        return ctx.scope

-    def activate(self, span, finish_on_close):
+    def activate(self, span: Span, finish_on_close: bool) -> Scope:
        """
        Makes a Span active.
        Args
-            span (Span): the span that should become active.
-            finish_on_close (Boolean): whether Span should be automatically
-                finished when Scope.close() is called.
+            span: the span that should become active.
+            finish_on_close: whether Span should be automatically finished when
+                Scope.close() is called.

        Returns:
            Scope to control the end of the active period for
@ -112,8 +115,8 @@ class _LogContextScope(Scope):
    def __init__(
        self,
        manager: LogContextScopeManager,
-        span,
-        logcontext,
+        span: Span,
+        logcontext: LoggingContext,
        enter_logcontext: bool,
        finish_on_close: bool,
    ):
@ -121,13 +124,13 @@ class _LogContextScope(Scope):
        Args:
            manager:
                the manager that is responsible for this scope.
-            span (Span):
+            span:
                the opentracing span which this scope represents the local
                lifetime for.
-            logcontext (LogContext):
-                the logcontext to which this scope is attached.
+            logcontext:
+                the log context to which this scope is attached.
            enter_logcontext:
-                if True the logcontext will be exited when the scope is finished
+                if True the log context will be exited when the scope is finished
            finish_on_close:
                if True finish the span when the scope is closed
        """
--- a/synapse/module_api/init.py
+++ b/synapse/module_api/init.py
@ -35,6 +35,7 @@ from typing_extensions import ParamSpec
 from twisted.internet import defer
 from twisted.web.resource import Resource

+from synapse.api import errors
 from synapse.api.errors import SynapseError
 from synapse.events import EventBase
 from synapse.events.presence_router import (
--- a/synapse/push/bulk_push_rule_evaluator.py
+++ b/synapse/push/bulk_push_rule_evaluator.py
@ -17,7 +17,6 @@ import itertools
 import logging
 from typing import TYPE_CHECKING, Any, Dict, Iterable, List, Optional, Set, Tuple, Union

-import attr
 from prometheus_client import Counter

 from synapse.api.constants import EventTypes, Membership, RelationTypes
@ -26,13 +25,11 @@ from synapse.events import EventBase, relation_from_event
 from synapse.events.snapshot import EventContext
 from synapse.state import POWER_KEY
 from synapse.storage.databases.main.roommember import EventIdMembership
-from synapse.util.async_helpers import Linearizer
-from synapse.util.caches import CacheMetric, register_cache
-from synapse.util.caches.descriptors import lru_cache
-from synapse.util.caches.lrucache import LruCache
+from synapse.storage.state import StateFilter
+from synapse.util.caches import register_cache
 from synapse.util.metrics import measure_func
+from synapse.visibility import filter_event_for_clients_with_state

-from ..storage.state import StateFilter
 from .push_rule_evaluator import PushRuleEvaluatorForEvent

 if TYPE_CHECKING:
@ -48,15 +45,6 @@ push_rules_state_size_counter = Counter(
    "synapse_push_bulk_push_rule_evaluator_push_rules_state_size_counter", ""
 )

-# Measures whether we use the fast path of using state deltas, or if we have to
-# recalculate from scratch
-push_rules_delta_state_cache_metric = register_cache(
-    "cache",
-    "push_rules_delta_state_cache_metric",
-    cache=[],  # Meaningless size, as this isn't a cache that stores values
-    resizable=False,
-)
-

 STATE_EVENT_TYPES_TO_MARK_UNREAD = {
    EventTypes.Topic,
@ -111,10 +99,6 @@ class BulkPushRuleEvaluator:
        self.clock = hs.get_clock()
        self._event_auth_handler = hs.get_event_auth_handler()

-        # Used by `RulesForRoom` to ensure only one thing mutates the cache at a
-        # time. Keyed off room_id.
-        self._rules_linearizer = Linearizer(name="rules_for_room")
-
        self.room_push_rule_cache_metrics = register_cache(
            "cache",
            "room_push_rule_cache",
@ -126,48 +110,48 @@ class BulkPushRuleEvaluator:
        self._relations_match_enabled = self.hs.config.experimental.msc3772_enabled

    async def _get_rules_for_event(
-        self, event: EventBase, context: EventContext
+        self,
+        event: EventBase,
    ) -> Dict[str, List[Dict[str, Any]]]:
-        """This gets the rules for all users in the room at the time of the event,
-        as well as the push rules for the invitee if the event is an invite.
+        """Get the push rules for all users who may need to be notified about
+        the event.
+
+        Note: this does not check if the user is allowed to see the event.

        Returns:
-            dict of user_id -> push_rules
+            Mapping of user ID to their push rules.
        """
-        room_id = event.room_id
+        # We get the users who may need to be notified by first fetching the
+        # local users currently in the room, finding those that have push rules,
+        # and *then* checking which users are actually allowed to see the event.
+        #
+        # The alternative is to first fetch all users that were joined at the
+        # event, but that requires fetching the full state at the event, which
+        # may be expensive for large rooms with few local users.

-        rules_for_room_data = self._get_rules_for_room(room_id)
-        rules_for_room = RulesForRoom(
-            hs=self.hs,
-            room_id=room_id,
-            rules_for_room_cache=self._get_rules_for_room.cache,
-            room_push_rule_cache_metrics=self.room_push_rule_cache_metrics,
-            linearizer=self._rules_linearizer,
-            cached_data=rules_for_room_data,
-        )
-
-        rules_by_user = await rules_for_room.get_rules(event, context)
+        local_users = await self.store.get_local_users_in_room(event.room_id)

        # if this event is an invite event, we may need to run rules for the user
        # who's been invited, otherwise they won't get told they've been invited
-        if event.type == "m.room.member" and event.content["membership"] == "invite":
+        if event.type == EventTypes.Member and event.membership == Membership.INVITE:
            invited = event.state_key
-            if invited and self.hs.is_mine_id(invited):
-                rules_by_user = dict(rules_by_user)
-                rules_by_user[invited] = await self.store.get_push_rules_for_user(
-                    invited
-                )
+            if invited and self.hs.is_mine_id(invited) and invited not in local_users:
+                local_users = list(local_users)
+                local_users.append(invited)
+
+        rules_by_user = await self.store.bulk_get_push_rules(local_users)
+
+        logger.debug("Users in room: %s", local_users)
+
+        if logger.isEnabledFor(logging.DEBUG):
+            logger.debug(
+                "Returning push rules for %r %r",
+                event.room_id,
+                list(rules_by_user.keys()),
+            )

        return rules_by_user

-    @lru_cache()
-    def _get_rules_for_room(self, room_id: str) -> "RulesForRoomData":
-        """Get the current RulesForRoomData object for the given room id"""
-        # It's important that the RulesForRoomData object gets added to self._get_rules_for_room.cache
-        # before any lookup methods get called on it as otherwise there may be
-        # a race if invalidate_all gets called (which assumes its in the cache)
-        return RulesForRoomData()
-
    async def _get_power_levels_and_sender_level(
        self, event: EventBase, context: EventContext
    ) -> Tuple[dict, int]:
@ -262,10 +246,12 @@ class BulkPushRuleEvaluator:

        count_as_unread = _should_count_as_unread(event, context)

-        rules_by_user = await self._get_rules_for_event(event, context)
+        rules_by_user = await self._get_rules_for_event(event)
        actions_by_user: Dict[str, List[Union[dict, str]]] = {}

-        room_members = await self.store.get_joined_users_from_context(event, context)
+        room_member_count = await self.store.get_number_joined_users_in_room(
+            event.room_id
+        )

        (
            power_levels,
@ -278,30 +264,36 @@ class BulkPushRuleEvaluator:

        evaluator = PushRuleEvaluatorForEvent(
            event,
-            len(room_members),
+            room_member_count,
            sender_power_level,
            power_levels,
            relations,
            self._relations_match_enabled,
        )

-        # If the event is not a state event check if any users ignore the sender.
-        if not event.is_state():
-            ignorers = await self.store.ignored_by(event.sender)
-        else:
-            ignorers = frozenset()
+        users = rules_by_user.keys()
+        profiles = await self.store.get_subset_users_in_room_with_profiles(
+            event.room_id, users
+        )
+
+        # This is a check for the case where user joins a room without being
+        # allowed to see history, and then the server receives a delayed event
+        # from before the user joined, which they should not be pushed for
+        uids_with_visibility = await filter_event_for_clients_with_state(
+            self.store, users, event, context
+        )

        for uid, rules in rules_by_user.items():
            if event.sender == uid:
                continue

-            if uid in ignorers:
+            if uid not in uids_with_visibility:
                continue

            display_name = None
-            profile_info = room_members.get(uid)
-            if profile_info:
-                display_name = profile_info.display_name
+            profile = profiles.get(uid)
+            if profile:
+                display_name = profile.display_name

            if not display_name:
                # Handle the case where we are pushing a membership event to
@ -346,283 +338,3 @@ MemberMap = Dict[str, Optional[EventIdMembership]]
 Rule = Dict[str, dict]
 RulesByUser = Dict[str, List[Rule]]
 StateGroup = Union[object, int]
-
-
-@attr.s(slots=True, auto_attribs=True)
-class RulesForRoomData:
-    """The data stored in the cache by `RulesForRoom`.
-
-    We don't store `RulesForRoom` directly in the cache as we want our caches to
-    *only* include data, and not references to e.g. the data stores.
-    """
-
-    # event_id -> EventIdMembership
-    member_map: MemberMap = attr.Factory(dict)
-    # user_id -> rules
-    rules_by_user: RulesByUser = attr.Factory(dict)
-
-    # The last state group we updated the caches for. If the state_group of
-    # a new event comes along, we know that we can just return the cached
-    # result.
-    # On invalidation of the rules themselves (if the user changes them),
-    # we invalidate everything and set state_group to `object()`
-    state_group: StateGroup = attr.Factory(object)
-
-    # A sequence number to keep track of when we're allowed to update the
-    # cache. We bump the sequence number when we invalidate the cache. If
-    # the sequence number changes while we're calculating stuff we should
-    # not update the cache with it.
-    sequence: int = 0
-
-    # A cache of user_ids that we *know* aren't interesting, e.g. user_ids
-    # owned by AS's, or remote users, etc. (I.e. users we will never need to
-    # calculate push for)
-    # These never need to be invalidated as we will never set up push for
-    # them.
-    uninteresting_user_set: Set[str] = attr.Factory(set)
-
-
-class RulesForRoom:
-    """Caches push rules for users in a room.
-
-    This efficiently handles users joining/leaving the room by not invalidating
-    the entire cache for the room.
-
-    A new instance is constructed for each call to
-    `BulkPushRuleEvaluator._get_rules_for_event`, with the cached data from
-    previous calls passed in.
-    """
-
-    def __init__(
-        self,
-        hs: "HomeServer",
-        room_id: str,
-        rules_for_room_cache: LruCache,
-        room_push_rule_cache_metrics: CacheMetric,
-        linearizer: Linearizer,
-        cached_data: RulesForRoomData,
-    ):
-        """
-        Args:
-            hs: The HomeServer object.
-            room_id: The room ID.
-            rules_for_room_cache: The cache object that caches these
-                RoomsForUser objects.
-            room_push_rule_cache_metrics: The metrics object
-            linearizer: The linearizer used to ensure only one thing mutates
-                the cache at a time. Keyed off room_id
-            cached_data: Cached data from previous calls to `self.get_rules`,
-                can be mutated.
-        """
-        self.room_id = room_id
-        self.is_mine_id = hs.is_mine_id
-        self.store = hs.get_datastores().main
-        self.room_push_rule_cache_metrics = room_push_rule_cache_metrics
-
-        # Used to ensure only one thing mutates the cache at a time. Keyed off
-        # room_id.
-        self.linearizer = linearizer
-
-        self.data = cached_data
-
-        # We need to be clever on the invalidating caches callbacks, as
-        # otherwise the invalidation callback holds a reference to the object,
-        # potentially causing it to leak.
-        # To get around this we pass a function that on invalidations looks ups
-        # the RoomsForUser entry in the cache, rather than keeping a reference
-        # to self around in the callback.
-        self.invalidate_all_cb = _Invalidation(rules_for_room_cache, room_id)
-
-    async def get_rules(
-        self, event: EventBase, context: EventContext
-    ) -> Dict[str, List[Dict[str, dict]]]:
-        """Given an event context return the rules for all users who are
-        currently in the room.
-        """
-        state_group = context.state_group
-
-        if state_group and self.data.state_group == state_group:
-            logger.debug("Using cached rules for %r", self.room_id)
-            self.room_push_rule_cache_metrics.inc_hits()
-            return self.data.rules_by_user
-
-        async with self.linearizer.queue(self.room_id):
-            if state_group and self.data.state_group == state_group:
-                logger.debug("Using cached rules for %r", self.room_id)
-                self.room_push_rule_cache_metrics.inc_hits()
-                return self.data.rules_by_user
-
-            self.room_push_rule_cache_metrics.inc_misses()
-
-            ret_rules_by_user = {}
-            missing_member_event_ids = {}
-            if state_group and self.data.state_group == context.prev_group:
-                # If we have a simple delta then we can reuse most of the previous
-                # results.
-                ret_rules_by_user = self.data.rules_by_user
-                current_state_ids = context.delta_ids
-
-                push_rules_delta_state_cache_metric.inc_hits()
-            else:
-                current_state_ids = await context.get_current_state_ids()
-                push_rules_delta_state_cache_metric.inc_misses()
-            # Ensure the state IDs exist.
-            assert current_state_ids is not None
-
-            push_rules_state_size_counter.inc(len(current_state_ids))
-
-            logger.debug(
-                "Looking for member changes in %r %r", state_group, current_state_ids
-            )
-
-            # Loop through to see which member events we've seen and have rules
-            # for and which we need to fetch
-            for key in current_state_ids:
-                typ, user_id = key
-                if typ != EventTypes.Member:
-                    continue
-
-                if user_id in self.data.uninteresting_user_set:
-                    continue
-
-                if not self.is_mine_id(user_id):
-                    self.data.uninteresting_user_set.add(user_id)
-                    continue
-
-                if self.store.get_if_app_services_interested_in_user(user_id):
-                    self.data.uninteresting_user_set.add(user_id)
-                    continue
-
-                event_id = current_state_ids[key]
-
-                res = self.data.member_map.get(event_id, None)
-                if res:
-                    if res.membership == Membership.JOIN:
-                        rules = self.data.rules_by_user.get(res.user_id, None)
-                        if rules:
-                            ret_rules_by_user[res.user_id] = rules
-                    continue
-
-                # If a user has left a room we remove their push rule. If they
-                # joined then we re-add it later in _update_rules_with_member_event_ids
-                ret_rules_by_user.pop(user_id, None)
-                missing_member_event_ids[user_id] = event_id
-
-            if missing_member_event_ids:
-                # If we have some member events we haven't seen, look them up
-                # and fetch push rules for them if appropriate.
-                logger.debug("Found new member events %r", missing_member_event_ids)
-                await self._update_rules_with_member_event_ids(
-                    ret_rules_by_user, missing_member_event_ids, state_group, event
-                )
-            else:
-                # The push rules didn't change but lets update the cache anyway
-                self.update_cache(
-                    self.data.sequence,
-                    members={},  # There were no membership changes
-                    rules_by_user=ret_rules_by_user,
-                    state_group=state_group,
-                )
-
-        if logger.isEnabledFor(logging.DEBUG):
-            logger.debug(
-                "Returning push rules for %r %r", self.room_id, ret_rules_by_user.keys()
-            )
-        return ret_rules_by_user
-
-    async def _update_rules_with_member_event_ids(
-        self,
-        ret_rules_by_user: Dict[str, list],
-        member_event_ids: Dict[str, str],
-        state_group: Optional[int],
-        event: EventBase,
-    ) -> None:
-        """Update the partially filled rules_by_user dict by fetching rules for
-        any newly joined users in the `member_event_ids` list.
-
-        Args:
-            ret_rules_by_user: Partially filled dict of push rules. Gets
-                updated with any new rules.
-            member_event_ids: Dict of user id to event id for membership events
-                that have happened since the last time we filled rules_by_user
-            state_group: The state group we are currently computing push rules
-                for. Used when updating the cache.
-            event: The event we are currently computing push rules for.
-        """
-        sequence = self.data.sequence
-
-        members = await self.store.get_membership_from_event_ids(
-            member_event_ids.values()
-        )
-
-        # If the event is a join event then it will be in current state events
-        # map but not in the DB, so we have to explicitly insert it.
-        if event.type == EventTypes.Member:
-            for event_id in member_event_ids.values():
-                if event_id == event.event_id:
-                    members[event_id] = EventIdMembership(
-                        user_id=event.state_key, membership=event.membership
-                    )
-
-        if logger.isEnabledFor(logging.DEBUG):
-            logger.debug("Found members %r: %r", self.room_id, members.values())
-
-        joined_user_ids = {
-            entry.user_id
-            for entry in members.values()
-            if entry and entry.membership == Membership.JOIN
-        }
-
-        logger.debug("Joined: %r", joined_user_ids)
-
-        # Previously we only considered users with pushers or read receipts in that
-        # room. We can't do this anymore because we use push actions to calculate unread
-        # counts, which don't rely on the user having pushers or sent a read receipt into
-        # the room. Therefore we just need to filter for local users here.
-        user_ids = list(filter(self.is_mine_id, joined_user_ids))
-
-        rules_by_user = await self.store.bulk_get_push_rules(
-            user_ids, on_invalidate=self.invalidate_all_cb
-        )
-
-        ret_rules_by_user.update(
-            item for item in rules_by_user.items() if item[0] is not None
-        )
-
-        self.update_cache(sequence, members, ret_rules_by_user, state_group)
-
-    def update_cache(
-        self,
-        sequence: int,
-        members: MemberMap,
-        rules_by_user: RulesByUser,
-        state_group: StateGroup,
-    ) -> None:
-        if sequence == self.data.sequence:
-            self.data.member_map.update(members)
-            self.data.rules_by_user = rules_by_user
-            self.data.state_group = state_group
-
-
-@attr.attrs(slots=True, frozen=True, auto_attribs=True)
-class _Invalidation:
-    # _Invalidation is passed as an `on_invalidate` callback to bulk_get_push_rules,
-    # which means that it it is stored on the bulk_get_push_rules cache entry. In order
-    # to ensure that we don't accumulate lots of redundant callbacks on the cache entry,
-    # we need to ensure that two _Invalidation objects are "equal" if they refer to the
-    # same `cache` and `room_id`.
-    #
-    # attrs provides suitable __hash__ and __eq__ methods, provided we remember to
-    # set `frozen=True`.
-
-    cache: LruCache
-    room_id: str
-
-    def __call__(self) -> None:
-        rules_data = self.cache.get(self.room_id, None, update_metrics=False)
-        if rules_data:
-            rules_data.sequence += 1
-            rules_data.state_group = object()
-            rules_data.member_map = {}
-            rules_data.rules_by_user = {}
-            push_rules_invalidation_counter.inc()
--- a/synapse/replication/http/init.py
+++ b/synapse/replication/http/init.py
@ -25,6 +25,7 @@ from synapse.replication.http import (
    push,
    register,
    send_event,
+    state,
    streams,
 )

@ -48,6 +49,7 @@ class ReplicationRestResource(JsonResource):
        streams.register_servlets(hs, self)
        account_data.register_servlets(hs, self)
        push.register_servlets(hs, self)
+        state.register_servlets(hs, self)

        # The following can't currently be instantiated on workers.
        if hs.config.worker.worker_app is None:
--- a/synapse/replication/http/federation.py
+++ b/synapse/replication/http/federation.py
@ -60,6 +60,9 @@ class ReplicationFederationSendEventsRestServlet(ReplicationEndpoint):
        {
            "max_stream_id": 32443,
        }
+
+    Responds with a 409 when a `PartialStateConflictError` is raised due to an event
+    context that needs to be recomputed due to the un-partial stating of a room.
    """

    NAME = "fed_send_events"
--- a/synapse/replication/http/send_event.py
+++ b/synapse/replication/http/send_event.py
@ -59,6 +59,9 @@ class ReplicationSendEventRestServlet(ReplicationEndpoint):

        { "stream_id": 12345, "event_id": "$abcdef..." }

+    Responds with a 409 when a `PartialStateConflictError` is raised due to an event
+    context that needs to be recomputed due to the un-partial stating of a room.
+
    The returned event ID may not match the sent event if it was deduplicated.
    """

--- a/synapse/replication/http/state.py
+++ b/synapse/replication/http/state.py
@ -0,0 +1,75 @@
+# Copyright 2022 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# 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.
+
+import logging
+from typing import TYPE_CHECKING, Tuple
+
+from twisted.web.server import Request
+
+from synapse.api.errors import SynapseError
+from synapse.http.server import HttpServer
+from synapse.replication.http._base import ReplicationEndpoint
+from synapse.types import JsonDict
+
+if TYPE_CHECKING:
+    from synapse.server import HomeServer
+
+logger = logging.getLogger(__name__)
+
+
+class ReplicationUpdateCurrentStateRestServlet(ReplicationEndpoint):
+    """Recalculates the current state for a room, and persists it.
+
+    The API looks like:
+
+        POST /_synapse/replication/update_current_state/:room_id
+
+        {}
+
+        200 OK
+
+        {}
+    """
+
+    NAME = "update_current_state"
+    PATH_ARGS = ("room_id",)
+
+    def __init__(self, hs: "HomeServer"):
+        super().__init__(hs)
+
+        self._state_handler = hs.get_state_handler()
+        self._events_shard_config = hs.config.worker.events_shard_config
+        self._instance_name = hs.get_instance_name()
+
+    @staticmethod
+    async def _serialize_payload(room_id: str) -> JsonDict:  # type: ignore[override]
+        return {}
+
+    async def _handle_request(  # type: ignore[override]
+        self, request: Request, room_id: str
+    ) -> Tuple[int, JsonDict]:
+        writer_instance = self._events_shard_config.get_instance(room_id)
+        if writer_instance != self._instance_name:
+            raise SynapseError(
+                400, "/update_current_state request was routed to the wrong worker"
+            )
+
+        await self._state_handler.update_current_state(room_id)
+
+        return 200, {}
+
+
+def register_servlets(hs: "HomeServer", http_server: HttpServer) -> None:
+    if hs.get_instance_name() in hs.config.worker.writers.events:
+        ReplicationUpdateCurrentStateRestServlet(hs).register(http_server)
--- a/synapse/rest/client/account_data.py
+++ b/synapse/rest/client/account_data.py
@ -15,11 +15,11 @@
 import logging
 from typing import TYPE_CHECKING, Tuple

-from synapse.api.errors import AuthError, NotFoundError, SynapseError
+from synapse.api.errors import AuthError, Codes, NotFoundError, SynapseError
 from synapse.http.server import HttpServer
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
 from synapse.http.site import SynapseRequest
-from synapse.types import JsonDict
+from synapse.types import JsonDict, RoomID

 from ._base import client_patterns

@ -104,6 +104,13 @@ class RoomAccountDataServlet(RestServlet):
        if user_id != requester.user.to_string():
            raise AuthError(403, "Cannot add account data for other users.")

+        if not RoomID.is_valid(room_id):
+            raise SynapseError(
+                400,
+                f"{room_id} is not a valid room ID",
+                Codes.INVALID_PARAM,
+            )
+
        body = parse_json_object_from_request(request)

        if account_data_type == "m.fully_read":
@ -111,6 +118,7 @@ class RoomAccountDataServlet(RestServlet):
                405,
                "Cannot set m.fully_read through this API."
                " Use /rooms/!roomId:server.name/read_markers",
+                Codes.BAD_JSON,
            )

        await self.handler.add_account_data_to_room(
@ -130,6 +138,13 @@ class RoomAccountDataServlet(RestServlet):
        if user_id != requester.user.to_string():
            raise AuthError(403, "Cannot get account data for other users.")

+        if not RoomID.is_valid(room_id):
+            raise SynapseError(
+                400,
+                f"{room_id} is not a valid room ID",
+                Codes.INVALID_PARAM,
+            )
+
        event = await self.store.get_account_data_for_room_and_type(
            user_id, room_id, account_data_type
        )
--- a/synapse/rest/client/versions.py
+++ b/synapse/rest/client/versions.py
@ -95,6 +95,8 @@ class VersionsRestServlet(RestServlet):
                    "org.matrix.msc3026.busy_presence": self.config.experimental.msc3026_enabled,
                    # Supports receiving private read receipts as per MSC2285
                    "org.matrix.msc2285": self.config.experimental.msc2285_enabled,
+                    # Supports filtering of /publicRooms by room type MSC3827
+                    "org.matrix.msc3827": self.config.experimental.msc3827_enabled,
                    # Adds support for importing historical messages as per MSC2716
                    "org.matrix.msc2716": self.config.experimental.msc2716_enabled,
                    # Adds support for jump to date endpoints (/timestamp_to_event) as per MSC3030
--- a/synapse/rest/media/v1/media_storage.py
+++ b/synapse/rest/media/v1/media_storage.py
@ -154,7 +154,9 @@ class MediaStorage:
                        # Note that we'll delete the stored media, due to the
                        # try/except below. The media also won't be stored in
                        # the DB.
-                        raise SpamMediaException(errcode=spam_check)
+                        # We currently ignore any additional field returned by
+                        # the spam-check API.
+                        raise SpamMediaException(errcode=spam_check[0])

                    for provider in self.storage_providers:
                        await provider.store_file(path, file_info)
--- a/synapse/state/init.py
+++ b/synapse/state/init.py
@ -43,6 +43,7 @@ from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, StateResolutionVersio
 from synapse.events import EventBase
 from synapse.events.snapshot import EventContext
 from synapse.logging.context import ContextResourceUsage
+from synapse.replication.http.state import ReplicationUpdateCurrentStateRestServlet
 from synapse.state import v1, v2
 from synapse.storage.databases.main.events_worker import EventRedactBehaviour
 from synapse.storage.roommember import ProfileInfo
@ -129,6 +130,12 @@ class StateHandler:
        self.hs = hs
        self._state_resolution_handler = hs.get_state_resolution_handler()
        self._storage_controllers = hs.get_storage_controllers()
+        self._events_shard_config = hs.config.worker.events_shard_config
+        self._instance_name = hs.get_instance_name()
+
+        self._update_current_state_client = (
+            ReplicationUpdateCurrentStateRestServlet.make_client(hs)
+        )

    async def get_current_state_ids(
        self,
@ -249,8 +256,12 @@ class StateHandler:
                partial_state = True

            logger.debug("calling resolve_state_groups from compute_event_context")
+            # we've already taken into account partial state, so no need to wait for
+            # complete state here.
            entry = await self.resolve_state_groups_for_events(
-                event.room_id, event.prev_event_ids()
+                event.room_id,
+                event.prev_event_ids(),
+                await_full_state=False,
            )

            state_ids_before_event = entry.state
@ -335,7 +346,7 @@ class StateHandler:

    @measure_func()
    async def resolve_state_groups_for_events(
-        self, room_id: str, event_ids: Collection[str]
+        self, room_id: str, event_ids: Collection[str], await_full_state: bool = True
    ) -> _StateCacheEntry:
        """Given a list of event_ids this method fetches the state at each
        event, resolves conflicts between them and returns them.
@ -343,6 +354,8 @@ class StateHandler:
        Args:
            room_id
            event_ids
+            await_full_state: if true, will block if we do not yet have complete
+               state at these events.

        Returns:
            The resolved state
@ -350,7 +363,7 @@ class StateHandler:
        logger.debug("resolve_state_groups event_ids %s", event_ids)

        state_groups = await self._state_storage_controller.get_state_group_for_events(
-            event_ids
+            event_ids, await_full_state=await_full_state
        )

        state_group_ids = state_groups.values()
@ -417,6 +430,24 @@ class StateHandler:

        return {key: state_map[ev_id] for key, ev_id in new_state.items()}

+    async def update_current_state(self, room_id: str) -> None:
+        """Recalculates the current state for a room, and persists it.
+
+        Raises:
+            SynapseError(502): if all attempts to connect to the event persister worker
+                fail
+        """
+        writer_instance = self._events_shard_config.get_instance(room_id)
+        if writer_instance != self._instance_name:
+            await self._update_current_state_client(
+                instance_name=writer_instance,
+                room_id=room_id,
+            )
+            return
+
+        assert self._storage_controllers.persistence is not None
+        await self._storage_controllers.persistence.update_current_state(room_id)
+

@attr.s(slots=True, auto_attribs=True)
 class _StateResMetrics:
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@ -75,6 +75,15 @@ class SQLBaseStore(metaclass=ABCMeta):
            self._attempt_to_invalidate_cache(
                "get_users_in_room_with_profiles", (room_id,)
            )
+            self._attempt_to_invalidate_cache(
+                "get_number_joined_users_in_room", (room_id,)
+            )
+            self._attempt_to_invalidate_cache("get_local_users_in_room", (room_id,))
+
+        for user_id in members_changed:
+            self._attempt_to_invalidate_cache(
+                "get_user_in_room_with_profile", (room_id, user_id)
+            )

        # Purge other caches based on room state.
        self._attempt_to_invalidate_cache("get_room_summary", (room_id,))
--- a/synapse/storage/controllers/persist_events.py
+++ b/synapse/storage/controllers/persist_events.py
@ -22,6 +22,7 @@ from typing import (
    Any,
    Awaitable,
    Callable,
+    ClassVar,
    Collection,
    Deque,
    Dict,
@ -33,6 +34,7 @@ from typing import (
    Set,
    Tuple,
    TypeVar,
+    Union,
 )

 import attr
@ -111,9 +113,43 @@ times_pruned_extremities = Counter(


@attr.s(auto_attribs=True, slots=True)
-class _EventPersistQueueItem:
+class _PersistEventsTask:
+    """A batch of events to persist."""
+
+    name: ClassVar[str] = "persist_event_batch"  # used for opentracing
+
    events_and_contexts: List[Tuple[EventBase, EventContext]]
    backfilled: bool
+
+    def try_merge(self, task: "_EventPersistQueueTask") -> bool:
+        """Batches events with the same backfilled option together."""
+        if (
+            not isinstance(task, _PersistEventsTask)
+            or self.backfilled != task.backfilled
+        ):
+            return False
+
+        self.events_and_contexts.extend(task.events_and_contexts)
+        return True
+
+
+@attr.s(auto_attribs=True, slots=True)
+class _UpdateCurrentStateTask:
+    """A room whose current state needs recalculating."""
+
+    name: ClassVar[str] = "update_current_state"  # used for opentracing
+
+    def try_merge(self, task: "_EventPersistQueueTask") -> bool:
+        """Deduplicates consecutive recalculations of current state."""
+        return isinstance(task, _UpdateCurrentStateTask)
+
+
+_EventPersistQueueTask = Union[_PersistEventsTask, _UpdateCurrentStateTask]
+
+
+@attr.s(auto_attribs=True, slots=True)
+class _EventPersistQueueItem:
+    task: _EventPersistQueueTask
    deferred: ObservableDeferred

    parent_opentracing_span_contexts: List = attr.ib(factory=list)
@ -127,14 +163,16 @@ _PersistResult = TypeVar("_PersistResult")


 class _EventPeristenceQueue(Generic[_PersistResult]):
-    """Queues up events so that they can be persisted in bulk with only one
-    concurrent transaction per room.
+    """Queues up tasks so that they can be processed with only one concurrent
+    transaction per room.
+
+    Tasks can be bulk persistence of events or recalculation of a room's current state.
    """

    def __init__(
        self,
        per_item_callback: Callable[
-            [List[Tuple[EventBase, EventContext]], bool],
+            [str, _EventPersistQueueTask],
            Awaitable[_PersistResult],
        ],
    ):
@ -150,18 +188,17 @@ class _EventPeristenceQueue(Generic[_PersistResult]):
    async def add_to_queue(
        self,
        room_id: str,
-        events_and_contexts: Iterable[Tuple[EventBase, EventContext]],
-        backfilled: bool,
+        task: _EventPersistQueueTask,
    ) -> _PersistResult:
-        """Add events to the queue, with the given persist_event options.
+        """Add a task to the queue.

-        If we are not already processing events in this room, starts off a background
+        If we are not already processing tasks in this room, starts off a background
        process to to so, calling the per_item_callback for each item.

        Args:
            room_id (str):
-            events_and_contexts (list[(EventBase, EventContext)]):
-            backfilled (bool):
+            task (_EventPersistQueueTask): A _PersistEventsTask or
+                _UpdateCurrentStateTask to process.

        Returns:
            the result returned by the `_per_item_callback` passed to
@ -169,26 +206,20 @@ class _EventPeristenceQueue(Generic[_PersistResult]):
        """
        queue = self._event_persist_queues.setdefault(room_id, deque())

-        # if the last item in the queue has the same `backfilled` setting,
-        # we can just add these new events to that item.
-        if queue and queue[-1].backfilled == backfilled:
+        if queue and queue[-1].task.try_merge(task):
+            # the new task has been merged into the last task in the queue
            end_item = queue[-1]
        else:
-            # need to make a new queue item
            deferred: ObservableDeferred[_PersistResult] = ObservableDeferred(
                defer.Deferred(), consumeErrors=True
            )

            end_item = _EventPersistQueueItem(
-                events_and_contexts=[],
-                backfilled=backfilled,
+                task=task,
                deferred=deferred,
            )
            queue.append(end_item)

-        # add our events to the queue item
-        end_item.events_and_contexts.extend(events_and_contexts)
-
        # also add our active opentracing span to the item so that we get a link back
        span = opentracing.active_span()
        if span:
@ -202,7 +233,7 @@ class _EventPeristenceQueue(Generic[_PersistResult]):

        # add another opentracing span which links to the persist trace.
        with opentracing.start_active_span_follows_from(
-            "persist_event_batch_complete", (end_item.opentracing_span_context,)
+            f"{task.name}_complete", (end_item.opentracing_span_context,)
        ):
            pass

@ -234,16 +265,14 @@ class _EventPeristenceQueue(Generic[_PersistResult]):
                for item in queue:
                    try:
                        with opentracing.start_active_span_follows_from(
-                            "persist_event_batch",
+                            item.task.name,
                            item.parent_opentracing_span_contexts,
                            inherit_force_tracing=True,
                        ) as scope:
                            if scope:
                                item.opentracing_span_context = scope.span.context

-                            ret = await self._per_item_callback(
-                                item.events_and_contexts, item.backfilled
-                            )
+                            ret = await self._per_item_callback(room_id, item.task)
                    except Exception:
                        with PreserveLoggingContext():
                            item.deferred.errback()
@ -292,9 +321,32 @@ class EventsPersistenceStorageController:
        self._clock = hs.get_clock()
        self._instance_name = hs.get_instance_name()
        self.is_mine_id = hs.is_mine_id
-        self._event_persist_queue = _EventPeristenceQueue(self._persist_event_batch)
+        self._event_persist_queue = _EventPeristenceQueue(
+            self._process_event_persist_queue_task
+        )
        self._state_resolution_handler = hs.get_state_resolution_handler()

+    async def _process_event_persist_queue_task(
+        self,
+        room_id: str,
+        task: _EventPersistQueueTask,
+    ) -> Dict[str, str]:
+        """Callback for the _event_persist_queue
+
+        Returns:
+            A dictionary of event ID to event ID we didn't persist as we already
+            had another event persisted with the same TXN ID.
+        """
+        if isinstance(task, _PersistEventsTask):
+            return await self._persist_event_batch(room_id, task)
+        elif isinstance(task, _UpdateCurrentStateTask):
+            await self._update_current_state(room_id, task)
+            return {}
+        else:
+            raise AssertionError(
+                f"Found an unexpected task type in event persistence queue: {task}"
+            )
+
    @opentracing.trace
    async def persist_events(
        self,
@ -315,6 +367,10 @@ class EventsPersistenceStorageController:
            if they were deduplicated due to an event already existing that
            matched the transaction ID; the existing event is returned in such
            a case.
+
+        Raises:
+            PartialStateConflictError: if attempting to persist a partial state event in
+                a room that has been un-partial stated.
        """
        partitioned: Dict[str, List[Tuple[EventBase, EventContext]]] = {}
        for event, ctx in events_and_contexts:
@ -325,7 +381,8 @@ class EventsPersistenceStorageController:
        ) -> Dict[str, str]:
            room_id, evs_ctxs = item
            return await self._event_persist_queue.add_to_queue(
-                room_id, evs_ctxs, backfilled=backfilled
+                room_id,
+                _PersistEventsTask(events_and_contexts=evs_ctxs, backfilled=backfilled),
            )

        ret_vals = await yieldable_gather_results(enqueue, partitioned.items())
@ -363,12 +420,19 @@ class EventsPersistenceStorageController:
            latest persisted event. The returned event may not match the given
            event if it was deduplicated due to an existing event matching the
            transaction ID.
+
+        Raises:
+            PartialStateConflictError: if attempting to persist a partial state event in
+                a room that has been un-partial stated.
        """
        # add_to_queue returns a map from event ID to existing event ID if the
        # event was deduplicated. (The dict may also include other entries if
        # the event was persisted in a batch with other events.)
        replaced_events = await self._event_persist_queue.add_to_queue(
-            event.room_id, [(event, context)], backfilled=backfilled
+            event.room_id,
+            _PersistEventsTask(
+                events_and_contexts=[(event, context)], backfilled=backfilled
+            ),
        )
        replaced_event = replaced_events.get(event.event_id)
        if replaced_event:
@ -383,20 +447,22 @@ class EventsPersistenceStorageController:

    async def update_current_state(self, room_id: str) -> None:
        """Recalculate the current state for a room, and persist it"""
+        await self._event_persist_queue.add_to_queue(
+            room_id,
+            _UpdateCurrentStateTask(),
+        )
+
+    async def _update_current_state(
+        self, room_id: str, _task: _UpdateCurrentStateTask
+    ) -> None:
+        """Callback for the _event_persist_queue
+
+        Recalculates the current state for a room, and persists it.
+        """
        state = await self._calculate_current_state(room_id)
        delta = await self._calculate_state_delta(room_id, state)

-        # TODO(faster_joins): get a real stream ordering, to make this work correctly
-        #    across workers.
-        #    https://github.com/matrix-org/synapse/issues/12994
-        #
-        # TODO(faster_joins): this can race against event persistence, in which case we
-        #    will end up with incorrect state. Perhaps we should make this a job we
-        #    farm out to the event persister thread, somehow.
-        #    https://github.com/matrix-org/synapse/issues/13007
-        #
-        stream_id = self.main_store.get_room_max_stream_ordering()
-        await self.persist_events_store.update_current_state(room_id, delta, stream_id)
+        await self.persist_events_store.update_current_state(room_id, delta)

    async def _calculate_current_state(self, room_id: str) -> StateMap[str]:
        """Calculate the current state of a room, based on the forward extremities
@ -441,9 +507,7 @@ class EventsPersistenceStorageController:
        return res.state

    async def _persist_event_batch(
-        self,
-        events_and_contexts: List[Tuple[EventBase, EventContext]],
-        backfilled: bool = False,
+        self, _room_id: str, task: _PersistEventsTask
    ) -> Dict[str, str]:
        """Callback for the _event_persist_queue

@ -453,7 +517,14 @@ class EventsPersistenceStorageController:
        Returns:
            A dictionary of event ID to event ID we didn't persist as we already
            had another event persisted with the same TXN ID.
+
+        Raises:
+            PartialStateConflictError: if attempting to persist a partial state event in
+                a room that has been un-partial stated.
        """
+        events_and_contexts = task.events_and_contexts
+        backfilled = task.backfilled
+
        replaced_events: Dict[str, str] = {}
        if not events_and_contexts:
            return replaced_events
--- a/synapse/storage/database.py
+++ b/synapse/storage/database.py
@ -366,10 +366,11 @@ class LoggingTransaction:
        *args: P.args,
        **kwargs: P.kwargs,
    ) -> R:
-        sql = self._make_sql_one_line(sql)
+        # Generate a one-line version of the SQL to better log it.
+        one_line_sql = self._make_sql_one_line(sql)

        # TODO(paul): Maybe use 'info' and 'debug' for values?
-        sql_logger.debug("[SQL] {%s} %s", self.name, sql)
+        sql_logger.debug("[SQL] {%s} %s", self.name, one_line_sql)

        sql = self.database_engine.convert_param_style(sql)
        if args:
@ -389,7 +390,7 @@ class LoggingTransaction:
                "db.query",
                tags={
                    opentracing.tags.DATABASE_TYPE: "sql",
-                    opentracing.tags.DATABASE_STATEMENT: sql,
+                    opentracing.tags.DATABASE_STATEMENT: one_line_sql,
                },
            ):
                return func(sql, *args, **kwargs)
--- a/synapse/storage/databases/main/init.py
+++ b/synapse/storage/databases/main/init.py
@ -87,7 +87,6 @@ class DataStore(
    RoomStore,
    RoomBatchStore,
    RegistrationStore,
-    StreamWorkerStore,
    ProfileStore,
    PresenceStore,
    TransactionWorkerStore,
@ -112,6 +111,7 @@ class DataStore(
    SearchStore,
    TagsStore,
    AccountDataStore,
+    StreamWorkerStore,
    OpenIdStore,
    ClientIpWorkerStore,
    DeviceStore,
--- a/synapse/storage/databases/main/event_push_actions.py
+++ b/synapse/storage/databases/main/event_push_actions.py
@ -25,8 +25,8 @@ from synapse.storage.database import (
    LoggingDatabaseConnection,
    LoggingTransaction,
 )
-from synapse.storage.databases.main.events_worker import EventsWorkerStore
 from synapse.storage.databases.main.receipts import ReceiptsWorkerStore
+from synapse.storage.databases.main.stream import StreamWorkerStore
 from synapse.util import json_encoder
 from synapse.util.caches.descriptors import cached

@ -122,7 +122,7 @@ def _deserialize_action(actions: str, is_highlight: bool) -> List[Union[dict, st
        return DEFAULT_NOTIF_ACTION


-class EventPushActionsWorkerStore(ReceiptsWorkerStore, EventsWorkerStore, SQLBaseStore):
+class EventPushActionsWorkerStore(ReceiptsWorkerStore, StreamWorkerStore, SQLBaseStore):
    def __init__(
        self,
        database: DatabasePool,
@ -143,7 +143,6 @@ class EventPushActionsWorkerStore(ReceiptsWorkerStore, EventsWorkerStore, SQLBas
            self._find_stream_orderings_for_times, 10 * 60 * 1000
        )

-        self._rotate_delay = 3
        self._rotate_count = 10000
        self._doing_notif_rotation = False
        if hs.config.worker.run_background_tasks:
@ -218,7 +217,7 @@ class EventPushActionsWorkerStore(ReceiptsWorkerStore, EventsWorkerStore, SQLBas
                retcol="event_id",
            )

-            stream_ordering = self.get_stream_id_for_event_txn(txn, event_id)  # type: ignore[attr-defined]
+            stream_ordering = self.get_stream_id_for_event_txn(txn, event_id)

        return self._get_unread_counts_by_pos_txn(
            txn, room_id, user_id, stream_ordering
@ -307,12 +306,22 @@ class EventPushActionsWorkerStore(ReceiptsWorkerStore, EventsWorkerStore, SQLBas
        actions that have been deleted from `event_push_actions` table.
        """

+        # If there have been no events in the room since the stream ordering,
+        # there can't be any push actions either.
+        if not self._events_stream_cache.has_entity_changed(room_id, stream_ordering):
+            return 0, 0
+
        clause = ""
        args = [user_id, room_id, stream_ordering]
        if max_stream_ordering is not None:
            clause = "AND ea.stream_ordering <= ?"
            args.append(max_stream_ordering)

+            # If the max stream ordering is less than the min stream ordering,
+            # then obviously there are zero push actions in that range.
+            if max_stream_ordering <= stream_ordering:
+                return 0, 0
+
        sql = f"""
            SELECT
               COUNT(CASE WHEN notif = 1 THEN 1 END),
@ -837,7 +846,6 @@ class EventPushActionsWorkerStore(ReceiptsWorkerStore, EventsWorkerStore, SQLBas
                )
                if caught_up:
                    break
-                await self.hs.get_clock().sleep(self._rotate_delay)

            # Finally we clear out old event push actions.
            await self._remove_old_push_actions_that_have_rotated()
@ -1003,13 +1011,17 @@ class EventPushActionsWorkerStore(ReceiptsWorkerStore, EventsWorkerStore, SQLBas
        sql = """
            SELECT user_id, room_id,
                coalesce(old.%s, 0) + upd.cnt,
-                upd.stream_ordering,
-                old.user_id
+                upd.stream_ordering
            FROM (
                SELECT user_id, room_id, count(*) as cnt,
-                    max(stream_ordering) as stream_ordering
-                FROM event_push_actions
-                WHERE ? < stream_ordering AND stream_ordering <= ?
+                    max(ea.stream_ordering) as stream_ordering
+                FROM event_push_actions AS ea
+                LEFT JOIN event_push_summary AS old USING (user_id, room_id)
+                WHERE ? < ea.stream_ordering AND ea.stream_ordering <= ?
+                    AND (
+                        old.last_receipt_stream_ordering IS NULL
+                        OR old.last_receipt_stream_ordering < ea.stream_ordering
+                    )
                    AND %s = 1
                GROUP BY user_id, room_id
            ) AS upd
@ -1032,7 +1044,6 @@ class EventPushActionsWorkerStore(ReceiptsWorkerStore, EventsWorkerStore, SQLBas
            summaries[(row[0], row[1])] = _EventPushSummary(
                unread_count=row[2],
                stream_ordering=row[3],
-                old_user_id=row[4],
                notif_count=0,
            )

@ -1053,57 +1064,27 @@ class EventPushActionsWorkerStore(ReceiptsWorkerStore, EventsWorkerStore, SQLBas
                summaries[(row[0], row[1])] = _EventPushSummary(
                    unread_count=0,
                    stream_ordering=row[3],
-                    old_user_id=row[4],
                    notif_count=row[2],
                )

        logger.info("Rotating notifications, handling %d rows", len(summaries))

-        # If the `old.user_id` above is NULL then we know there isn't already an
-        # entry in the table, so we simply insert it. Otherwise we update the
-        # existing table.
-        self.db_pool.simple_insert_many_txn(
+        self.db_pool.simple_upsert_many_txn(
            txn,
            table="event_push_summary",
-            keys=(
-                "user_id",
-                "room_id",
-                "notif_count",
-                "unread_count",
-                "stream_ordering",
-            ),
-            values=[
+            key_names=("user_id", "room_id"),
+            key_values=[(user_id, room_id) for user_id, room_id in summaries],
+            value_names=("notif_count", "unread_count", "stream_ordering"),
+            value_values=[
                (
-                    user_id,
-                    room_id,
                    summary.notif_count,
                    summary.unread_count,
                    summary.stream_ordering,
                )
-                for ((user_id, room_id), summary) in summaries.items()
-                if summary.old_user_id is None
+                for summary in summaries.values()
            ],
        )

-        txn.execute_batch(
-            """
-                UPDATE event_push_summary
-                SET notif_count = ?, unread_count = ?, stream_ordering = ?
-                WHERE user_id = ? AND room_id = ?
-            """,
-            (
-                (
-                    summary.notif_count,
-                    summary.unread_count,
-                    summary.stream_ordering,
-                    user_id,
-                    room_id,
-                )
-                for ((user_id, room_id), summary) in summaries.items()
-                if summary.old_user_id is not None
-            ),
-        )
-
        txn.execute(
            "UPDATE event_push_summary_stream_ordering SET stream_ordering = ?",
            (rotate_to_stream_ordering,),
@ -1131,12 +1112,12 @@ class EventPushActionsWorkerStore(ReceiptsWorkerStore, EventsWorkerStore, SQLBas
        ) -> bool:
            # We don't want to clear out too much at a time, so we bound our
            # deletes.
-            batch_size = 10000
+            batch_size = self._rotate_count

            txn.execute(
                """
                SELECT stream_ordering FROM event_push_actions
-                WHERE stream_ordering < ? AND highlight = 0
+                WHERE stream_ordering <= ? AND highlight = 0
                ORDER BY stream_ordering ASC LIMIT 1 OFFSET ?
            """,
                (
@ -1151,10 +1132,12 @@ class EventPushActionsWorkerStore(ReceiptsWorkerStore, EventsWorkerStore, SQLBas
            else:
                stream_ordering = max_stream_ordering_to_delete

+            # We need to use a inclusive bound here to handle the case where a
+            # single stream ordering has more than `batch_size` rows.
            txn.execute(
                """
                DELETE FROM event_push_actions
-                WHERE stream_ordering < ? AND highlight = 0
+                WHERE stream_ordering <= ? AND highlight = 0
                """,
                (stream_ordering,),
            )
@ -1283,5 +1266,4 @@ class _EventPushSummary:

    unread_count: int
    stream_ordering: int
-    old_user_id: str
    notif_count: int
--- a/synapse/storage/databases/main/events.py
+++ b/synapse/storage/databases/main/events.py
@ -16,6 +16,7 @@
 import itertools
 import logging
 from collections import OrderedDict
+from http import HTTPStatus
 from typing import (
    TYPE_CHECKING,
    Any,
@ -35,6 +36,7 @@ from prometheus_client import Counter

 import synapse.metrics
 from synapse.api.constants import EventContentFields, EventTypes, RelationTypes
+from synapse.api.errors import Codes, SynapseError
 from synapse.api.room_versions import RoomVersions
 from synapse.events import EventBase, relation_from_event
 from synapse.events.snapshot import EventContext
@ -69,6 +71,24 @@ event_counter = Counter(
 )


+class PartialStateConflictError(SynapseError):
+    """An internal error raised when attempting to persist an event with partial state
+    after the room containing the event has been un-partial stated.
+
+    This error should be handled by recomputing the event context and trying again.
+
+    This error has an HTTP status code so that it can be transported over replication.
+    It should not be exposed to clients.
+    """
+
+    def __init__(self) -> None:
+        super().__init__(
+            HTTPStatus.CONFLICT,
+            msg="Cannot persist partial state event in un-partial stated room",
+            errcode=Codes.UNKNOWN,
+        )
+
+
@attr.s(slots=True, auto_attribs=True)
 class DeltaState:
    """Deltas to use to update the `current_state_events` table.
@ -154,6 +174,10 @@ class PersistEventsStore:

        Returns:
            Resolves when the events have been persisted
+
+        Raises:
+            PartialStateConflictError: if attempting to persist a partial state event in
+                a room that has been un-partial stated.
        """

        # We want to calculate the stream orderings as late as possible, as
@ -354,6 +378,9 @@ class PersistEventsStore:
                For each room, a list of the event ids which are the forward
                extremities.

+        Raises:
+            PartialStateConflictError: if attempting to persist a partial state event in
+                a room that has been un-partial stated.
        """
        state_delta_for_room = state_delta_for_room or {}
        new_forward_extremities = new_forward_extremities or {}
@ -980,16 +1007,16 @@ class PersistEventsStore:
        self,
        room_id: str,
        state_delta: DeltaState,
-        stream_id: int,
    ) -> None:
        """Update the current state stored in the datatabase for the given room"""

-        await self.db_pool.runInteraction(
-            "update_current_state",
-            self._update_current_state_txn,
-            state_delta_by_room={room_id: state_delta},
-            stream_id=stream_id,
-        )
+        async with self._stream_id_gen.get_next() as stream_ordering:
+            await self.db_pool.runInteraction(
+                "update_current_state",
+                self._update_current_state_txn,
+                state_delta_by_room={room_id: state_delta},
+                stream_id=stream_ordering,
+            )

    def _update_current_state_txn(
        self,
@ -1304,6 +1331,10 @@ class PersistEventsStore:

        Returns:
            new list, without events which are already in the events table.
+
+        Raises:
+            PartialStateConflictError: if attempting to persist a partial state event in
+                a room that has been un-partial stated.
        """
        txn.execute(
            "SELECT event_id, outlier FROM events WHERE event_id in (%s)"
@ -1766,6 +1797,18 @@ class PersistEventsStore:
                self.store.get_invited_rooms_for_local_user.invalidate,
                (event.state_key,),
            )
+            txn.call_after(
+                self.store.get_local_users_in_room.invalidate,
+                (event.room_id,),
+            )
+            txn.call_after(
+                self.store.get_number_joined_users_in_room.invalidate,
+                (event.room_id,),
+            )
+            txn.call_after(
+                self.store.get_user_in_room_with_profile.invalidate,
+                (event.room_id, event.state_key),
+            )

            # The `_get_membership_from_event_id` is immutable, except for the
            # case where we look up an event *before* persisting it.
@ -2215,6 +2258,11 @@ class PersistEventsStore:
        txn: LoggingTransaction,
        events_and_contexts: Collection[Tuple[EventBase, EventContext]],
    ) -> None:
+        """
+        Raises:
+            PartialStateConflictError: if attempting to persist a partial state event in
+                a room that has been un-partial stated.
+        """
        state_groups = {}
        for event, context in events_and_contexts:
            if event.internal_metadata.is_outlier():
@ -2239,19 +2287,37 @@ class PersistEventsStore:
        # if we have partial state for these events, record the fact. (This happens
        # here rather than in _store_event_txn because it also needs to happen when
        # we de-outlier an event.)
-        self.db_pool.simple_insert_many_txn(
-            txn,
-            table="partial_state_events",
-            keys=("room_id", "event_id"),
-            values=[
-                (
-                    event.room_id,
-                    event.event_id,
-                )
-                for event, ctx in events_and_contexts
-                if ctx.partial_state
-            ],
-        )
+        try:
+            self.db_pool.simple_insert_many_txn(
+                txn,
+                table="partial_state_events",
+                keys=("room_id", "event_id"),
+                values=[
+                    (
+                        event.room_id,
+                        event.event_id,
+                    )
+                    for event, ctx in events_and_contexts
+                    if ctx.partial_state
+                ],
+            )
+        except self.db_pool.engine.module.IntegrityError:
+            logger.info(
+                "Cannot persist events %s in rooms %s: room has been un-partial stated",
+                [
+                    event.event_id
+                    for event, ctx in events_and_contexts
+                    if ctx.partial_state
+                ],
+                list(
+                    {
+                        event.room_id
+                        for event, ctx in events_and_contexts
+                        if ctx.partial_state
+                    }
+                ),
+            )
+            raise PartialStateConflictError()

        self.db_pool.simple_upsert_many_txn(
            txn,
--- a/synapse/storage/databases/main/room.py
+++ b/synapse/storage/databases/main/room.py
@ -32,12 +32,17 @@ from typing import (

 import attr

-from synapse.api.constants import EventContentFields, EventTypes, JoinRules
+from synapse.api.constants import (
+    EventContentFields,
+    EventTypes,
+    JoinRules,
+    PublicRoomsFilterFields,
+)
 from synapse.api.errors import StoreError
 from synapse.api.room_versions import RoomVersion, RoomVersions
 from synapse.config.homeserver import HomeServerConfig
 from synapse.events import EventBase
-from synapse.storage._base import SQLBaseStore, db_to_json
+from synapse.storage._base import SQLBaseStore, db_to_json, make_in_list_sql_clause
 from synapse.storage.database import (
    DatabasePool,
    LoggingDatabaseConnection,
@ -199,10 +204,29 @@ class RoomWorkerStore(CacheInvalidationWorkerStore):
            desc="get_public_room_ids",
        )

+    def _construct_room_type_where_clause(
+        self, room_types: Union[List[Union[str, None]], None]
+    ) -> Tuple[Union[str, None], List[str]]:
+        if not room_types or not self.config.experimental.msc3827_enabled:
+            return None, []
+        else:
+            # We use None when we want get rooms without a type
+            is_null_clause = ""
+            if None in room_types:
+                is_null_clause = "OR room_type IS NULL"
+                room_types = [value for value in room_types if value is not None]
+
+            list_clause, args = make_in_list_sql_clause(
+                self.database_engine, "room_type", room_types
+            )
+
+            return f"({list_clause} {is_null_clause})", args
+
    async def count_public_rooms(
        self,
        network_tuple: Optional[ThirdPartyInstanceID],
        ignore_non_federatable: bool,
+        search_filter: Optional[dict],
    ) -> int:
        """Counts the number of public rooms as tracked in the room_stats_current
        and room_stats_state table.
@ -210,11 +234,20 @@ class RoomWorkerStore(CacheInvalidationWorkerStore):
        Args:
            network_tuple
            ignore_non_federatable: If true filters out non-federatable rooms
+            search_filter
        """

        def _count_public_rooms_txn(txn: LoggingTransaction) -> int:
            query_args = []

+            room_type_clause, args = self._construct_room_type_where_clause(
+                search_filter.get(PublicRoomsFilterFields.ROOM_TYPES, None)
+                if search_filter
+                else None
+            )
+            room_type_clause = f" AND {room_type_clause}" if room_type_clause else ""
+            query_args += args
+
            if network_tuple:
                if network_tuple.appservice_id:
                    published_sql = """
@ -249,6 +282,7 @@ class RoomWorkerStore(CacheInvalidationWorkerStore):
                        OR join_rules = '{JoinRules.KNOCK_RESTRICTED}'
                        OR history_visibility = 'world_readable'
                    )
+                    {room_type_clause}
                    AND joined_members > 0
            """

@ -347,8 +381,12 @@ class RoomWorkerStore(CacheInvalidationWorkerStore):
        if ignore_non_federatable:
            where_clauses.append("is_federatable")

-        if search_filter and search_filter.get("generic_search_term", None):
-            search_term = "%" + search_filter["generic_search_term"] + "%"
+        if search_filter and search_filter.get(
+            PublicRoomsFilterFields.GENERIC_SEARCH_TERM, None
+        ):
+            search_term = (
+                "%" + search_filter[PublicRoomsFilterFields.GENERIC_SEARCH_TERM] + "%"
+            )

            where_clauses.append(
                """
@ -365,6 +403,15 @@ class RoomWorkerStore(CacheInvalidationWorkerStore):
                search_term.lower(),
            ]

+        room_type_clause, args = self._construct_room_type_where_clause(
+            search_filter.get(PublicRoomsFilterFields.ROOM_TYPES, None)
+            if search_filter
+            else None
+        )
+        if room_type_clause:
+            where_clauses.append(room_type_clause)
+        query_args += args
+
        where_clause = ""
        if where_clauses:
            where_clause = " AND " + " AND ".join(where_clauses)
@ -373,7 +420,7 @@ class RoomWorkerStore(CacheInvalidationWorkerStore):
        sql = f"""
            SELECT
                room_id, name, topic, canonical_alias, joined_members,
-                avatar, history_visibility, guest_access, join_rules
+                avatar, history_visibility, guest_access, join_rules, room_type
            FROM (
                {published_sql}
            ) published
@ -1109,19 +1156,25 @@ class RoomWorkerStore(CacheInvalidationWorkerStore):
        return room_servers

    async def clear_partial_state_room(self, room_id: str) -> bool:
-        # this can race with incoming events, so we watch out for FK errors.
-        # TODO(faster_joins): this still doesn't completely fix the race, since the persist process
-        #   is not atomic. I fear we need an application-level lock.
-        #   https://github.com/matrix-org/synapse/issues/12988
+        """Clears the partial state flag for a room.
+
+        Args:
+            room_id: The room whose partial state flag is to be cleared.
+
+        Returns:
+            `True` if the partial state flag has been cleared successfully.
+
+            `False` if the partial state flag could not be cleared because the room
+            still contains events with partial state.
+        """
        try:
            await self.db_pool.runInteraction(
                "clear_partial_state_room", self._clear_partial_state_room_txn, room_id
            )
            return True
-        except self.db_pool.engine.module.DatabaseError as e:
-            # TODO(faster_joins): how do we distinguish between FK errors and other errors?
-            #   https://github.com/matrix-org/synapse/issues/12988
-            logger.warning(
+        except self.db_pool.engine.module.IntegrityError as e:
+            # Assume that any `IntegrityError`s are due to partial state events.
+            logger.info(
                "Exception while clearing lazy partial-state-room %s, retrying: %s",
                room_id,
                e,
@ -1166,6 +1219,7 @@ class _BackgroundUpdates:
    POPULATE_ROOM_DEPTH_MIN_DEPTH2 = "populate_room_depth_min_depth2"
    REPLACE_ROOM_DEPTH_MIN_DEPTH = "replace_room_depth_min_depth"
    POPULATE_ROOMS_CREATOR_COLUMN = "populate_rooms_creator_column"
+    ADD_ROOM_TYPE_COLUMN = "add_room_type_column"


 _REPLACE_ROOM_DEPTH_SQL_COMMANDS = (
@ -1200,6 +1254,11 @@ class RoomBackgroundUpdateStore(SQLBaseStore):
            self._background_add_rooms_room_version_column,
        )

+        self.db_pool.updates.register_background_update_handler(
+            _BackgroundUpdates.ADD_ROOM_TYPE_COLUMN,
+            self._background_add_room_type_column,
+        )
+
        # BG updates to change the type of room_depth.min_depth
        self.db_pool.updates.register_background_update_handler(
            _BackgroundUpdates.POPULATE_ROOM_DEPTH_MIN_DEPTH2,
@ -1569,6 +1628,69 @@ class RoomBackgroundUpdateStore(SQLBaseStore):

        return batch_size

+    async def _background_add_room_type_column(
+        self, progress: JsonDict, batch_size: int
+    ) -> int:
+        """Background update to go and add room_type information to `room_stats_state`
+        table from `event_json` table.
+        """
+
+        last_room_id = progress.get("room_id", "")
+
+        def _background_add_room_type_column_txn(
+            txn: LoggingTransaction,
+        ) -> bool:
+            sql = """
+                SELECT state.room_id, json FROM event_json
+                INNER JOIN current_state_events AS state USING (event_id)
+                WHERE state.room_id > ? AND type = 'm.room.create'
+                ORDER BY state.room_id
+                LIMIT ?
+            """
+
+            txn.execute(sql, (last_room_id, batch_size))
+            room_id_to_create_event_results = txn.fetchall()
+
+            new_last_room_id = None
+            for room_id, event_json in room_id_to_create_event_results:
+                event_dict = db_to_json(event_json)
+
+                room_type = event_dict.get("content", {}).get(
+                    EventContentFields.ROOM_TYPE, None
+                )
+                if isinstance(room_type, str):
+                    self.db_pool.simple_update_txn(
+                        txn,
+                        table="room_stats_state",
+                        keyvalues={"room_id": room_id},
+                        updatevalues={"room_type": room_type},
+                    )
+
+                new_last_room_id = room_id
+
+            if new_last_room_id is None:
+                return True
+
+            self.db_pool.updates._background_update_progress_txn(
+                txn,
+                _BackgroundUpdates.ADD_ROOM_TYPE_COLUMN,
+                {"room_id": new_last_room_id},
+            )
+
+            return False
+
+        end = await self.db_pool.runInteraction(
+            "_background_add_room_type_column",
+            _background_add_room_type_column_txn,
+        )
+
+        if end:
+            await self.db_pool.updates._end_background_update(
+                _BackgroundUpdates.ADD_ROOM_TYPE_COLUMN
+            )
+
+        return batch_size
+

 class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore):
    def __init__(
--- a/synapse/storage/databases/main/roommember.py
+++ b/synapse/storage/databases/main/roommember.py
@ -212,6 +212,60 @@ class RoomMemberWorkerStore(EventsWorkerStore):
        txn.execute(sql, (room_id, Membership.JOIN))
        return [r[0] for r in txn]

+    @cached()
+    def get_user_in_room_with_profile(
+        self, room_id: str, user_id: str
+    ) -> Dict[str, ProfileInfo]:
+        raise NotImplementedError()
+
+    @cachedList(
+        cached_method_name="get_user_in_room_with_profile", list_name="user_ids"
+    )
+    async def get_subset_users_in_room_with_profiles(
+        self, room_id: str, user_ids: Collection[str]
+    ) -> Dict[str, ProfileInfo]:
+        """Get a mapping from user ID to profile information for a list of users
+        in a given room.
+
+        The profile information comes directly from this room's `m.room.member`
+        events, and so may be specific to this room rather than part of a user's
+        global profile. To avoid privacy leaks, the profile data should only be
+        revealed to users who are already in this room.
+
+        Args:
+            room_id: The ID of the room to retrieve the users of.
+            user_ids: a list of users in the room to run the query for
+
+        Returns:
+                A mapping from user ID to ProfileInfo.
+        """
+
+        def _get_subset_users_in_room_with_profiles(
+            txn: LoggingTransaction,
+        ) -> Dict[str, ProfileInfo]:
+            clause, ids = make_in_list_sql_clause(
+                self.database_engine, "m.user_id", user_ids
+            )
+
+            sql = """
+                SELECT state_key, display_name, avatar_url FROM room_memberships as m
+                INNER JOIN current_state_events as c
+                ON m.event_id = c.event_id
+                AND m.room_id = c.room_id
+                AND m.user_id = c.state_key
+                WHERE c.type = 'm.room.member' AND c.room_id = ? AND m.membership = ? AND %s
+            """ % (
+                clause,
+            )
+            txn.execute(sql, (room_id, Membership.JOIN, *ids))
+
+            return {r[0]: ProfileInfo(display_name=r[1], avatar_url=r[2]) for r in txn}
+
+        return await self.db_pool.runInteraction(
+            "get_subset_users_in_room_with_profiles",
+            _get_subset_users_in_room_with_profiles,
+        )
+
    @cached(max_entries=100000, iterable=True)
    async def get_users_in_room_with_profiles(
        self, room_id: str
@ -337,6 +391,15 @@ class RoomMemberWorkerStore(EventsWorkerStore):
            "get_room_summary", _get_room_summary_txn
        )

+    @cached()
+    async def get_number_joined_users_in_room(self, room_id: str) -> int:
+        return await self.db_pool.simple_select_one_onecol(
+            table="current_state_events",
+            keyvalues={"room_id": room_id, "membership": Membership.JOIN},
+            retcol="COUNT(*)",
+            desc="get_number_joined_users_in_room",
+        )
+
    @cached()
    async def get_invited_rooms_for_local_user(
        self, user_id: str
@ -416,6 +479,17 @@ class RoomMemberWorkerStore(EventsWorkerStore):
        user_id: str,
        membership_list: List[str],
    ) -> List[RoomsForUser]:
+        """Get all the rooms for this *local* user where the membership for this user
+        matches one in the membership list.
+
+        Args:
+            user_id: The user ID.
+            membership_list: A list of synapse.api.constants.Membership
+                    values which the user must be in.
+
+        Returns:
+            The RoomsForUser that the user matches the membership types.
+        """
        # Paranoia check.
        if not self.hs.is_mine_id(user_id):
            raise Exception(
@ -444,6 +518,18 @@ class RoomMemberWorkerStore(EventsWorkerStore):

        return results

+    @cached(iterable=True)
+    async def get_local_users_in_room(self, room_id: str) -> List[str]:
+        """
+        Retrieves a list of the current roommembers who are local to the server.
+        """
+        return await self.db_pool.simple_select_onecol(
+            table="local_current_membership",
+            keyvalues={"room_id": room_id, "membership": Membership.JOIN},
+            retcol="user_id",
+            desc="get_local_users_in_room",
+        )
+
    async def get_local_current_membership_for_user_in_room(
        self, user_id: str, room_id: str
    ) -> Tuple[Optional[str], Optional[str]]:
--- a/synapse/storage/databases/main/stats.py
+++ b/synapse/storage/databases/main/stats.py
@ -16,7 +16,7 @@
 import logging
 from enum import Enum
 from itertools import chain
-from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple, cast
+from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple, Union, cast

 from typing_extensions import Counter

@ -238,6 +238,7 @@ class StatsStore(StateDeltasStore):
        * avatar
        * canonical_alias
        * guest_access
+        * room_type

        A is_federatable key can also be included with a boolean value.

@ -263,6 +264,7 @@ class StatsStore(StateDeltasStore):
            "avatar",
            "canonical_alias",
            "guest_access",
+            "room_type",
        ):
            field = fields.get(col, sentinel)
            if field is not sentinel and (not isinstance(field, str) or "\0" in field):
@ -572,7 +574,7 @@ class StatsStore(StateDeltasStore):

        state_event_map = await self.get_events(event_ids, get_prev_content=False)  # type: ignore[attr-defined]

-        room_state = {
+        room_state: Dict[str, Union[None, bool, str]] = {
            "join_rules": None,
            "history_visibility": None,
            "encryption": None,
@ -581,6 +583,7 @@ class StatsStore(StateDeltasStore):
            "avatar": None,
            "canonical_alias": None,
            "is_federatable": True,
+            "room_type": None,
        }

        for event in state_event_map.values():
@ -604,6 +607,9 @@ class StatsStore(StateDeltasStore):
                room_state["is_federatable"] = (
                    event.content.get(EventContentFields.FEDERATE, True) is True
                )
+                room_type = event.content.get(EventContentFields.ROOM_TYPE)
+                if isinstance(room_type, str):
+                    room_state["room_type"] = room_type

        await self.update_room_state(room_id, room_state)

--- a/synapse/storage/databases/main/stream.py
+++ b/synapse/storage/databases/main/stream.py
@ -46,10 +46,12 @@ from typing import (
    Set,
    Tuple,
    cast,
+    overload,
 )

 import attr
 from frozendict import frozendict
+from typing_extensions import Literal

 from twisted.internet import defer

@ -795,6 +797,24 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
        )
        return RoomStreamToken(topo, stream_ordering)

+    @overload
+    def get_stream_id_for_event_txn(
+        self,
+        txn: LoggingTransaction,
+        event_id: str,
+        allow_none: Literal[False] = False,
+    ) -> int:
+        ...
+
+    @overload
+    def get_stream_id_for_event_txn(
+        self,
+        txn: LoggingTransaction,
+        event_id: str,
+        allow_none: bool = False,
+    ) -> Optional[int]:
+        ...
+
    def get_stream_id_for_event_txn(
        self,
        txn: LoggingTransaction,
--- a/synapse/storage/schema/main/delta/72/01add_room_type_to_state_stats.sql
+++ b/synapse/storage/schema/main/delta/72/01add_room_type_to_state_stats.sql
@ -0,0 +1,19 @@
+/* Copyright 2022 The Matrix.org Foundation C.I.C
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * 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.
+ */
+
+ALTER TABLE room_stats_state ADD room_type TEXT;
+
+INSERT INTO background_updates (update_name, progress_json)
+    VALUES ('add_room_type_column', '{}');
--- a/synapse/util/init.py
+++ b/synapse/util/init.py
@ -20,6 +20,7 @@ from typing import Any, Callable, Dict, Generator, Optional
 import attr
 from frozendict import frozendict
 from matrix_common.versionstring import get_distribution_version_string
+from typing_extensions import ParamSpec

 from twisted.internet import defer, task
 from twisted.internet.defer import Deferred
@ -82,6 +83,9 @@ def unwrapFirstError(failure: Failure) -> Failure:
    return failure.value.subFailure  # type: ignore[union-attr]  # Issue in Twisted's annotations


+P = ParamSpec("P")
+
+
@attr.s(slots=True)
 class Clock:
    """
@ -110,7 +114,7 @@ class Clock:
        return int(self.time() * 1000)

    def looping_call(
-        self, f: Callable, msec: float, *args: Any, **kwargs: Any
+        self, f: Callable[P, object], msec: float, *args: P.args, **kwargs: P.kwargs
    ) -> LoopingCall:
        """Call a function repeatedly.

--- a/synapse/util/caches/lrucache.py
+++ b/synapse/util/caches/lrucache.py
@ -109,7 +109,7 @@ GLOBAL_ROOT = ListNode["_Node"].create_root_node()

@wrap_as_background_process("LruCache._expire_old_entries")
 async def _expire_old_entries(
-    clock: Clock, expiry_seconds: int, autotune_config: Optional[dict]
+    clock: Clock, expiry_seconds: float, autotune_config: Optional[dict]
 ) -> None:
    """Walks the global cache list to find cache entries that haven't been
    accessed in the given number of seconds, or if a given memory threshold has been breached.
--- a/synapse/visibility.py
+++ b/synapse/visibility.py
@ -13,16 +13,21 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
+from enum import Enum, auto
 from typing import Collection, Dict, FrozenSet, List, Optional, Tuple

+import attr
 from typing_extensions import Final

 from synapse.api.constants import EventTypes, HistoryVisibility, Membership
 from synapse.events import EventBase
+from synapse.events.snapshot import EventContext
 from synapse.events.utils import prune_event
 from synapse.storage.controllers import StorageControllers
+from synapse.storage.databases.main import DataStore
 from synapse.storage.state import StateFilter
 from synapse.types import RetentionPolicy, StateMap, get_domain_from_id
+from synapse.util import Clock

 logger = logging.getLogger(__name__)

@ -106,157 +111,19 @@ async def filter_events_for_client(
    filter_override = user_id in storage.hs.config.meow.filter_override

    def allowed(event: EventBase) -> Optional[EventBase]:
-        """
-        Args:
-            event: event to check
-
-        Returns:
-           None if the user cannot see this event at all
-
-           a redacted copy of the event if they can only see a redacted
-           version
-
-           the original event if they can see it as normal.
-        """
-        # Only run some checks if these events aren't about to be sent to clients. This is
-        # because, if this is not the case, we're probably only checking if the users can
-        # see events in the room at that point in the DAG, and that shouldn't be decided
-        # on those checks.
-        if filter_send_to_client and not filter_override:
-            if event.type == EventTypes.Dummy:
-                return None
-
-            if not event.is_state() and event.sender in ignore_list:
-                return None
-
-            # Until MSC2261 has landed we can't redact malicious alias events, so for
-            # now we temporarily filter out m.room.aliases entirely to mitigate
-            # abuse, while we spec a better solution to advertising aliases
-            # on rooms.
-            if event.type == EventTypes.Aliases:
-                return None
-
-            # Don't try to apply the room's retention policy if the event is a state
-            # event, as MSC1763 states that retention is only considered for non-state
-            # events.
-            if not event.is_state():
-                retention_policy = retention_policies[event.room_id]
-                max_lifetime = retention_policy.max_lifetime
-
-                if max_lifetime is not None:
-                    oldest_allowed_ts = storage.main.clock.time_msec() - max_lifetime
-
-                    if event.origin_server_ts < oldest_allowed_ts:
-                        return None
-        # meow: even with filter_override, we want to filter ignored users
-        elif filter_send_to_client and not event.is_state() and event.sender in ignore_list:
-            return None
-
-
-        if event.event_id in always_include_ids:
-            return event
-
-        # we need to handle outliers separately, since we don't have the room state.
-        if event.internal_metadata.outlier:
-            # Normally these can't be seen by clients, but we make an exception for
-            # for out-of-band membership events (eg, incoming invites, or rejections of
-            # said invite) for the user themselves.
-            if event.type == EventTypes.Member and event.state_key == user_id:
-                logger.debug("Returning out-of-band-membership event %s", event)
-                return event
-
-            return None
-
-        state = event_id_to_state[event.event_id]
-
-        # get the room_visibility at the time of the event.
-        visibility = get_effective_room_visibility_from_state(state)
-
-        # Always allow history visibility events on boundaries. This is done
-        # by setting the effective visibility to the least restrictive
-        # of the old vs new.
-        if event.type == EventTypes.RoomHistoryVisibility:
-            prev_content = event.unsigned.get("prev_content", {})
-            prev_visibility = prev_content.get("history_visibility", None)
-
-            if prev_visibility not in VISIBILITY_PRIORITY:
-                prev_visibility = HistoryVisibility.SHARED
-
-            new_priority = VISIBILITY_PRIORITY.index(visibility)
-            old_priority = VISIBILITY_PRIORITY.index(prev_visibility)
-            if old_priority < new_priority:
-                visibility = prev_visibility
-
-        # likewise, if the event is the user's own membership event, use
-        # the 'most joined' membership
-        membership = None
-        if event.type == EventTypes.Member and event.state_key == user_id:
-            membership = event.content.get("membership", None)
-            if membership not in MEMBERSHIP_PRIORITY:
-                membership = "leave"
-
-            prev_content = event.unsigned.get("prev_content", {})
-            prev_membership = prev_content.get("membership", None)
-            if prev_membership not in MEMBERSHIP_PRIORITY:
-                prev_membership = "leave"
-
-            # Always allow the user to see their own leave events, otherwise
-            # they won't see the room disappear if they reject the invite
-            #
-            # (Note this doesn't work for out-of-band invite rejections, which don't
-            # have prev_state populated. They are handled above in the outlier code.)
-            if membership == "leave" and (
-                prev_membership == "join" or prev_membership == "invite"
-            ):
-                return event
-
-            new_priority = MEMBERSHIP_PRIORITY.index(membership)
-            old_priority = MEMBERSHIP_PRIORITY.index(prev_membership)
-            if old_priority < new_priority:
-                membership = prev_membership
-
-        # otherwise, get the user's membership at the time of the event.
-        if membership is None:
-            membership_event = state.get((EventTypes.Member, user_id), None)
-            if membership_event:
-                membership = membership_event.membership
-
-        # if the user was a member of the room at the time of the event,
-        # they can see it.
-        if membership == Membership.JOIN:
-            return event
-
-        # otherwise, it depends on the room visibility.
-
-        if visibility == HistoryVisibility.JOINED:
-            # we weren't a member at the time of the event, so we can't
-            # see this event.
-            return None
-
-        elif visibility == HistoryVisibility.INVITED:
-            # user can also see the event if they were *invited* at the time
-            # of the event.
-            return event if membership == Membership.INVITE else None
-
-        elif visibility == HistoryVisibility.SHARED and is_peeking:
-            # if the visibility is shared, users cannot see the event unless
-            # they have *subsequently* joined the room (or were members at the
-            # time, of course)
-            #
-            # XXX: if the user has subsequently joined and then left again,
-            # ideally we would share history up to the point they left. But
-            # we don't know when they left. We just treat it as though they
-            # never joined, and restrict access.
-            return None
-
-        # the visibility is either shared or world_readable, and the user was
-        # not a member at the time. We allow it, provided the original sender
-        # has not requested their data to be erased, in which case, we return
-        # a redacted version.
-        if erased_senders[event.sender]:
-            return prune_event(event)
-
-        return event
+        return _check_client_allowed_to_see_event(
+            user_id=user_id,
+            event=event,
+            clock=storage.main.clock,
+            filter_send_to_client=filter_send_to_client,
+            sender_ignored=event.sender in ignore_list,
+            always_include_ids=always_include_ids,
+            retention_policy=retention_policies[room_id],
+            state=event_id_to_state.get(event.event_id),
+            is_peeking=is_peeking,
+            sender_erased=erased_senders.get(event.sender, False),
+            filter_override=filter_override,
+        )

    # Check each event: gives an iterable of None or (a potentially modified)
    # EventBase.
@ -266,9 +133,394 @@ async def filter_events_for_client(
    return [ev for ev in filtered_events if ev]


+async def filter_event_for_clients_with_state(
+    store: DataStore,
+    user_ids: Collection[str],
+    event: EventBase,
+    context: EventContext,
+    is_peeking: bool = False,
+    filter_send_to_client: bool = True,
+) -> Collection[str]:
+    """
+    Checks to see if an event is visible to the users in the list at the time of
+    the event.
+
+    Note: This does *not* check if the sender of the event was erased.
+
+    Args:
+        store: databases
+        user_ids: user_ids to be checked
+        event: the event to be checked
+        context: EventContext for the event to be checked
+        is_peeking: Whether the users are peeking into the room, ie not
+            currently joined
+        filter_send_to_client: Whether we're checking an event that's going to be
+            sent to a client. This might not always be the case since this function can
+            also be called to check whether a user can see the state at a given point.
+
+    Returns:
+        Collection of user IDs for whom the event is visible
+    """
+    # None of the users should see the event if it is soft_failed
+    if event.internal_metadata.is_soft_failed():
+        return []
+
+    # Make a set for all user IDs that haven't been filtered out by a check.
+    allowed_user_ids = set(user_ids)
+
+    # Only run some checks if these events aren't about to be sent to clients. This is
+    # because, if this is not the case, we're probably only checking if the users can
+    # see events in the room at that point in the DAG, and that shouldn't be decided
+    # on those checks.
+    if filter_send_to_client:
+        ignored_by = await store.ignored_by(event.sender)
+        retention_policy = await store.get_retention_policy_for_room(event.room_id)
+
+        for user_id in user_ids:
+            if (
+                _check_filter_send_to_client(
+                    event,
+                    store.clock,
+                    retention_policy,
+                    sender_ignored=user_id in ignored_by,
+                )
+                == _CheckFilter.DENIED
+            ):
+                allowed_user_ids.discard(user_id)
+
+    if event.internal_metadata.outlier:
+        # Normally these can't be seen by clients, but we make an exception for
+        # for out-of-band membership events (eg, incoming invites, or rejections of
+        # said invite) for the user themselves.
+        if event.type == EventTypes.Member and event.state_key in allowed_user_ids:
+            logger.debug("Returning out-of-band-membership event %s", event)
+            return {event.state_key}
+
+        return set()
+
+    # First we get just the history visibility in case its shared/world-readable
+    # room.
+    visibility_state_map = await _get_state_map(
+        store, event, context, StateFilter.from_types([_HISTORY_VIS_KEY])
+    )
+
+    visibility = get_effective_room_visibility_from_state(visibility_state_map)
+    if (
+        _check_history_visibility(event, visibility, is_peeking=is_peeking)
+        == _CheckVisibility.ALLOWED
+    ):
+        return allowed_user_ids
+
+    # The history visibility isn't lax, so we now need to fetch the membership
+    # events of all the users.
+
+    filter_list = []
+    for user_id in allowed_user_ids:
+        filter_list.append((EventTypes.Member, user_id))
+    filter_list.append((EventTypes.RoomHistoryVisibility, ""))
+
+    state_filter = StateFilter.from_types(filter_list)
+    state_map = await _get_state_map(store, event, context, state_filter)
+
+    # Now we check whether the membership allows each user to see the event.
+    return {
+        user_id
+        for user_id in allowed_user_ids
+        if _check_membership(user_id, event, visibility, state_map, is_peeking).allowed
+    }
+
+
+async def _get_state_map(
+    store: DataStore, event: EventBase, context: EventContext, state_filter: StateFilter
+) -> StateMap[EventBase]:
+    """Helper function for getting a `StateMap[EventBase]` from an `EventContext`"""
+    state_map = await context.get_prev_state_ids(state_filter)
+
+    # Use events rather than event ids as content from the events are needed in
+    # _check_visibility
+    event_map = await store.get_events(state_map.values(), get_prev_content=False)
+
+    updated_state_map = {}
+    for state_key, event_id in state_map.items():
+        state_event = event_map.get(event_id)
+        if state_event:
+            updated_state_map[state_key] = state_event
+
+    if event.is_state():
+        current_state_key = (event.type, event.state_key)
+        # Add current event to updated_state_map, we need to do this here as it
+        # may not have been persisted to the db yet
+        updated_state_map[current_state_key] = event
+
+    return updated_state_map
+
+
+def _check_client_allowed_to_see_event(
+    user_id: str,
+    event: EventBase,
+    clock: Clock,
+    filter_send_to_client: bool,
+    is_peeking: bool,
+    always_include_ids: FrozenSet[str],
+    sender_ignored: bool,
+    retention_policy: RetentionPolicy,
+    state: Optional[StateMap[EventBase]],
+    sender_erased: bool,
+    filter_override: bool,
+) -> Optional[EventBase]:
+    """Check with the given user is allowed to see the given event
+
+    See `filter_events_for_client` for details about args
+
+    Args:
+        user_id
+        event
+        clock
+        filter_send_to_client
+        is_peeking
+        always_include_ids
+        sender_ignored: Whether the user is ignoring the event sender
+        retention_policy: The retention policy of the room
+        state: The state at the event, unless its an outlier
+        sender_erased: Whether the event sender has been marked as "erased"
+        filter_override: meow
+
+    Returns:
+        None if the user cannot see this event at all
+
+        a redacted copy of the event if they can only see a redacted
+        version
+
+        the original event if they can see it as normal.
+    """
+    # Only run some checks if these events aren't about to be sent to clients. This is
+    # because, if this is not the case, we're probably only checking if the users can
+    # see events in the room at that point in the DAG, and that shouldn't be decided
+    # on those checks.
+    if filter_send_to_client and not filter_override:
+        if (
+            _check_filter_send_to_client(event, clock, retention_policy, sender_ignored)
+            == _CheckFilter.DENIED
+        ):
+            return None
+    # meow: even with filter_override, we want to filter ignored users
+    elif filter_send_to_client and not event.is_state() and sender_ignored:
+        return None
+
+    if event.event_id in always_include_ids:
+        return event
+
+    # we need to handle outliers separately, since we don't have the room state.
+    if event.internal_metadata.outlier:
+        # Normally these can't be seen by clients, but we make an exception for
+        # for out-of-band membership events (eg, incoming invites, or rejections of
+        # said invite) for the user themselves.
+        if event.type == EventTypes.Member and event.state_key == user_id:
+            logger.debug("Returning out-of-band-membership event %s", event)
+            return event
+
+        return None
+
+    if state is None:
+        raise Exception("Missing state for non-outlier event")
+
+    # get the room_visibility at the time of the event.
+    visibility = get_effective_room_visibility_from_state(state)
+
+    # Check if the room has lax history visibility, allowing us to skip
+    # membership checks.
+    #
+    # We can only do this check if the sender has *not* been erased, as if they
+    # have we need to check the user's membership.
+    if (
+        not sender_erased
+        and _check_history_visibility(event, visibility, is_peeking)
+        == _CheckVisibility.ALLOWED
+    ):
+        return event
+
+    membership_result = _check_membership(user_id, event, visibility, state, is_peeking)
+    if not membership_result.allowed:
+        return None
+
+    # If the sender has been erased and the user was not joined at the time, we
+    # must only return the redacted form.
+    if sender_erased and not membership_result.joined:
+        event = prune_event(event)
+
+    return event
+
+
+@attr.s(frozen=True, slots=True, auto_attribs=True)
+class _CheckMembershipReturn:
+    "Return value of _check_membership"
+    allowed: bool
+    joined: bool
+
+
+def _check_membership(
+    user_id: str,
+    event: EventBase,
+    visibility: str,
+    state: StateMap[EventBase],
+    is_peeking: bool,
+) -> _CheckMembershipReturn:
+    """Check whether the user can see the event due to their membership
+
+    Returns:
+        True if they can, False if they can't, plus the membership of the user
+        at the event.
+    """
+    # If the event is the user's own membership event, use the 'most joined'
+    # membership
+    membership = None
+    if event.type == EventTypes.Member and event.state_key == user_id:
+        membership = event.content.get("membership", None)
+        if membership not in MEMBERSHIP_PRIORITY:
+            membership = "leave"
+
+        prev_content = event.unsigned.get("prev_content", {})
+        prev_membership = prev_content.get("membership", None)
+        if prev_membership not in MEMBERSHIP_PRIORITY:
+            prev_membership = "leave"
+
+        # Always allow the user to see their own leave events, otherwise
+        # they won't see the room disappear if they reject the invite
+        #
+        # (Note this doesn't work for out-of-band invite rejections, which don't
+        # have prev_state populated. They are handled above in the outlier code.)
+        if membership == "leave" and (
+            prev_membership == "join" or prev_membership == "invite"
+        ):
+            return _CheckMembershipReturn(True, membership == Membership.JOIN)
+
+        new_priority = MEMBERSHIP_PRIORITY.index(membership)
+        old_priority = MEMBERSHIP_PRIORITY.index(prev_membership)
+        if old_priority < new_priority:
+            membership = prev_membership
+
+    # otherwise, get the user's membership at the time of the event.
+    if membership is None:
+        membership_event = state.get((EventTypes.Member, user_id), None)
+        if membership_event:
+            membership = membership_event.membership
+
+    # if the user was a member of the room at the time of the event,
+    # they can see it.
+    if membership == Membership.JOIN:
+        return _CheckMembershipReturn(True, True)
+
+    # otherwise, it depends on the room visibility.
+
+    if visibility == HistoryVisibility.JOINED:
+        # we weren't a member at the time of the event, so we can't
+        # see this event.
+        return _CheckMembershipReturn(False, False)
+
+    elif visibility == HistoryVisibility.INVITED:
+        # user can also see the event if they were *invited* at the time
+        # of the event.
+        return _CheckMembershipReturn(membership == Membership.INVITE, False)
+
+    elif visibility == HistoryVisibility.SHARED and is_peeking:
+        # if the visibility is shared, users cannot see the event unless
+        # they have *subsequently* joined the room (or were members at the
+        # time, of course)
+        #
+        # XXX: if the user has subsequently joined and then left again,
+        # ideally we would share history up to the point they left. But
+        # we don't know when they left. We just treat it as though they
+        # never joined, and restrict access.
+        return _CheckMembershipReturn(False, False)
+
+    # The visibility is either shared or world_readable, and the user was
+    # not a member at the time. We allow it.
+    return _CheckMembershipReturn(True, False)
+
+
+class _CheckFilter(Enum):
+    MAYBE_ALLOWED = auto()
+    DENIED = auto()
+
+
+def _check_filter_send_to_client(
+    event: EventBase,
+    clock: Clock,
+    retention_policy: RetentionPolicy,
+    sender_ignored: bool,
+) -> _CheckFilter:
+    """Apply checks for sending events to client
+
+    Returns:
+        True if might be allowed to be sent to clients, False if definitely not.
+    """
+
+    if event.type == EventTypes.Dummy:
+        return _CheckFilter.DENIED
+
+    if not event.is_state() and sender_ignored:
+        return _CheckFilter.DENIED
+
+    # Until MSC2261 has landed we can't redact malicious alias events, so for
+    # now we temporarily filter out m.room.aliases entirely to mitigate
+    # abuse, while we spec a better solution to advertising aliases
+    # on rooms.
+    if event.type == EventTypes.Aliases:
+        return _CheckFilter.DENIED
+
+    # Don't try to apply the room's retention policy if the event is a state
+    # event, as MSC1763 states that retention is only considered for non-state
+    # events.
+    if not event.is_state():
+        max_lifetime = retention_policy.max_lifetime
+
+        if max_lifetime is not None:
+            oldest_allowed_ts = clock.time_msec() - max_lifetime
+
+            if event.origin_server_ts < oldest_allowed_ts:
+                return _CheckFilter.DENIED
+
+    return _CheckFilter.MAYBE_ALLOWED
+
+
+class _CheckVisibility(Enum):
+    ALLOWED = auto()
+    MAYBE_DENIED = auto()
+
+
+def _check_history_visibility(
+    event: EventBase, visibility: str, is_peeking: bool
+) -> _CheckVisibility:
+    """Check if event is allowed to be seen due to lax history visibility.
+
+    Returns:
+        True if user can definitely see the event, False if maybe not.
+    """
+    # Always allow history visibility events on boundaries. This is done
+    # by setting the effective visibility to the least restrictive
+    # of the old vs new.
+    if event.type == EventTypes.RoomHistoryVisibility:
+        prev_content = event.unsigned.get("prev_content", {})
+        prev_visibility = prev_content.get("history_visibility", None)
+
+        if prev_visibility not in VISIBILITY_PRIORITY:
+            prev_visibility = HistoryVisibility.SHARED
+
+        new_priority = VISIBILITY_PRIORITY.index(visibility)
+        old_priority = VISIBILITY_PRIORITY.index(prev_visibility)
+        if old_priority < new_priority:
+            visibility = prev_visibility
+
+    if visibility == HistoryVisibility.SHARED and not is_peeking:
+        return _CheckVisibility.ALLOWED
+    elif visibility == HistoryVisibility.WORLD_READABLE:
+        return _CheckVisibility.ALLOWED
+
+    return _CheckVisibility.MAYBE_DENIED
+
+
 def get_effective_room_visibility_from_state(state: StateMap[EventBase]) -> str:
    """Get the actual history vis, from a state map including the history_visibility event
-
    Handles missing and invalid history visibility events.
    """
    visibility_event = state.get(_HISTORY_VIS_KEY, None)
--- a/tests/logging/test_opentracing.py
+++ b/tests/logging/test_opentracing.py
@ -50,7 +50,7 @@ class LogContextScopeManagerTestCase(TestCase):
        # global variables that power opentracing. We create our own tracer instance
        # and test with it.

-        scope_manager = LogContextScopeManager({})
+        scope_manager = LogContextScopeManager()
        config = jaeger_client.config.Config(
            config={}, service_name="test", scope_manager=scope_manager
        )
--- a/tests/rest/admin/test_room.py
+++ b/tests/rest/admin/test_room.py
@ -1579,8 +1579,8 @@ class RoomTestCase(unittest.HomeserverTestCase):
            access_token=self.admin_user_tok,
        )
        self.assertEqual(HTTPStatus.OK, channel.code, msg=channel.json_body)
-        self.assertEqual(room_id, channel.json_body.get("rooms")[0].get("room_id"))
-        self.assertEqual("ж", channel.json_body.get("rooms")[0].get("name"))
+        self.assertEqual(room_id, channel.json_body["rooms"][0].get("room_id"))
+        self.assertEqual("ж", channel.json_body["rooms"][0].get("name"))

    def test_single_room(self) -> None:
        """Test that a single room can be requested correctly"""
--- a/tests/rest/admin/test_user.py
+++ b/tests/rest/admin/test_user.py
@ -1488,7 +1488,7 @@ class UserRestTestCase(unittest.HomeserverTestCase):

        if channel.code != HTTPStatus.OK:
            raise HttpResponseException(
-                channel.code, channel.result["reason"], channel.json_body
+                channel.code, channel.result["reason"], channel.result["body"]
            )

        # Set monthly active users to the limit
--- a/tests/rest/client/test_account.py
+++ b/tests/rest/client/test_account.py
@ -949,7 +949,7 @@ class ThreepidEmailRestTestCase(unittest.HomeserverTestCase):
        client_secret: str,
        next_link: Optional[str] = None,
        expect_code: int = 200,
-    ) -> str:
+    ) -> Optional[str]:
        """Request a validation token to add an email address to a user's account

        Args:
@ -959,7 +959,8 @@ class ThreepidEmailRestTestCase(unittest.HomeserverTestCase):
            expect_code: Expected return code of the call

        Returns:
-            The ID of the new threepid validation session
+            The ID of the new threepid validation session, or None if the response
+            did not contain a session ID.
        """
        body = {"client_secret": client_secret, "email": email, "send_attempt": 1}
        if next_link:
--- a/tests/rest/client/test_profile.py
+++ b/tests/rest/client/test_profile.py
@ -153,18 +153,22 @@ class ProfileTestCase(unittest.HomeserverTestCase):
        )
        self.assertEqual(channel.code, 400, channel.result)

-    def _get_displayname(self, name: Optional[str] = None) -> str:
+    def _get_displayname(self, name: Optional[str] = None) -> Optional[str]:
        channel = self.make_request(
            "GET", "/profile/%s/displayname" % (name or self.owner,)
        )
        self.assertEqual(channel.code, 200, channel.result)
-        return channel.json_body["displayname"]
+        # FIXME: If a user has no displayname set, Synapse returns 200 and omits a
+        # displayname from the response. This contradicts the spec, see #13137.
+        return channel.json_body.get("displayname")

-    def _get_avatar_url(self, name: Optional[str] = None) -> str:
+    def _get_avatar_url(self, name: Optional[str] = None) -> Optional[str]:
        channel = self.make_request(
            "GET", "/profile/%s/avatar_url" % (name or self.owner,)
        )
        self.assertEqual(channel.code, 200, channel.result)
+        # FIXME: If a user has no avatar set, Synapse returns 200 and omits an
+        # avatar_url from the response. This contradicts the spec, see #13137.
        return channel.json_body.get("avatar_url")

    @unittest.override_config({"max_avatar_size": 50})
--- a/tests/rest/client/test_relations.py
+++ b/tests/rest/client/test_relations.py
@ -800,7 +800,7 @@ class RelationPaginationTestCase(BaseRelationsTestCase):
            )
            expected_event_ids.append(channel.json_body["event_id"])

-        prev_token = ""
+        prev_token: Optional[str] = ""
        found_event_ids: List[str] = []
        for _ in range(20):
            from_token = ""
--- a/tests/rest/client/test_rooms.py
+++ b/tests/rest/client/test_rooms.py
@ -18,11 +18,11 @@
 """Tests REST events for /rooms paths."""

 import json
-from typing import Any, Dict, Iterable, List, Optional, Union
+from typing import Any, Dict, Iterable, List, Optional, Tuple, Union
 from unittest.mock import Mock, call
 from urllib import parse as urlparse

-# `Literal` appears with Python 3.8.
+from parameterized import param, parameterized
 from typing_extensions import Literal

 from twisted.test.proto_helpers import MemoryReactor
@ -33,7 +33,9 @@ from synapse.api.constants import (
    EventContentFields,
    EventTypes,
    Membership,
+    PublicRoomsFilterFields,
    RelationTypes,
+    RoomTypes,
 )
 from synapse.api.errors import Codes, HttpResponseException
 from synapse.handlers.pagination import PurgeStatus
@ -706,6 +708,21 @@ class RoomsCreateTestCase(RoomBase):

        self.assertEqual(200, channel.code, channel.result)
        self.assertTrue("room_id" in channel.json_body)
+        assert channel.resource_usage is not None
+        self.assertEqual(37, channel.resource_usage.db_txn_count)
+
+    def test_post_room_initial_state(self) -> None:
+        # POST with initial_state config key, expect new room id
+        channel = self.make_request(
+            "POST",
+            "/createRoom",
+            b'{"initial_state":[{"type": "m.bridge", "content": {}}]}',
+        )
+
+        self.assertEqual(200, channel.code, channel.result)
+        self.assertTrue("room_id" in channel.json_body)
+        assert channel.resource_usage is not None
+        self.assertEqual(41, channel.resource_usage.db_txn_count)

    def test_post_room_visibility_key(self) -> None:
        # POST with visibility config key, expect new room id
@ -813,14 +830,14 @@ class RoomsCreateTestCase(RoomBase):
        In this test, we use the more recent API in which callbacks return a `Union[Codes, Literal["NOT_SPAM"]]`.
        """

-        async def user_may_join_room(
+        async def user_may_join_room_codes(
            mxid: str,
            room_id: str,
            is_invite: bool,
        ) -> Codes:
            return Codes.CONSENT_NOT_GIVEN

-        join_mock = Mock(side_effect=user_may_join_room)
+        join_mock = Mock(side_effect=user_may_join_room_codes)
        self.hs.get_spam_checker()._user_may_join_room_callbacks.append(join_mock)

        channel = self.make_request(
@ -832,6 +849,25 @@ class RoomsCreateTestCase(RoomBase):

        self.assertEqual(join_mock.call_count, 0)

+        # Now change the return value of the callback to deny any join. Since we're
+        # creating the room, despite the return value, we should be able to join.
+        async def user_may_join_room_tuple(
+            mxid: str,
+            room_id: str,
+            is_invite: bool,
+        ) -> Tuple[Codes, dict]:
+            return Codes.INCOMPATIBLE_ROOM_VERSION, {}
+
+        join_mock.side_effect = user_may_join_room_tuple
+
+        channel = self.make_request(
+            "POST",
+            "/createRoom",
+            {},
+        )
+        self.assertEqual(channel.code, 200, channel.json_body)
+        self.assertEqual(join_mock.call_count, 0)
+

 class RoomTopicTestCase(RoomBase):
    """Tests /rooms/$room_id/topic REST events."""
@ -1111,13 +1147,15 @@ class RoomJoinTestCase(RoomBase):
        """

        # Register a dummy callback. Make it allow all room joins for now.
-        return_value: Union[Literal["NOT_SPAM"], Codes] = synapse.module_api.NOT_SPAM
+        return_value: Union[
+            Literal["NOT_SPAM"], Tuple[Codes, dict], Codes
+        ] = synapse.module_api.NOT_SPAM

        async def user_may_join_room(
            userid: str,
            room_id: str,
            is_invited: bool,
-        ) -> Union[Literal["NOT_SPAM"], Codes]:
+        ) -> Union[Literal["NOT_SPAM"], Tuple[Codes, dict], Codes]:
            return return_value

        # `spec` argument is needed for this function mock to have `__qualname__`, which
@ -1161,8 +1199,28 @@ class RoomJoinTestCase(RoomBase):
        )

        # Now make the callback deny all room joins, and check that a join actually fails.
+        # We pick an arbitrary Codes rather than the default `Codes.FORBIDDEN`.
        return_value = Codes.CONSENT_NOT_GIVEN
-        self.helper.join(self.room3, self.user2, expect_code=403, tok=self.tok2)
+        self.helper.invite(self.room3, self.user1, self.user2, tok=self.tok1)
+        self.helper.join(
+            self.room3,
+            self.user2,
+            expect_code=403,
+            expect_errcode=return_value,
+            tok=self.tok2,
+        )
+
+        # Now make the callback deny all room joins, and check that a join actually fails.
+        # As above, with the experimental extension that lets us return dictionaries.
+        return_value = (Codes.BAD_ALIAS, {"another_field": "12345"})
+        self.helper.join(
+            self.room3,
+            self.user2,
+            expect_code=403,
+            expect_errcode=return_value[0],
+            tok=self.tok2,
+            expect_additional_fields=return_value[1],
+        )


 class RoomJoinRatelimitTestCase(RoomBase):
@ -1312,6 +1370,97 @@ class RoomMessagesTestCase(RoomBase):
        channel = self.make_request("PUT", path, content)
        self.assertEqual(200, channel.code, msg=channel.result["body"])

+    @parameterized.expand(
+        [
+            # Allow
+            param(
+                name="NOT_SPAM", value="NOT_SPAM", expected_code=200, expected_fields={}
+            ),
+            param(name="False", value=False, expected_code=200, expected_fields={}),
+            # Block
+            param(
+                name="scalene string",
+                value="ANY OTHER STRING",
+                expected_code=403,
+                expected_fields={"errcode": "M_FORBIDDEN"},
+            ),
+            param(
+                name="True",
+                value=True,
+                expected_code=403,
+                expected_fields={"errcode": "M_FORBIDDEN"},
+            ),
+            param(
+                name="Code",
+                value=Codes.LIMIT_EXCEEDED,
+                expected_code=403,
+                expected_fields={"errcode": "M_LIMIT_EXCEEDED"},
+            ),
+            param(
+                name="Tuple",
+                value=(Codes.SERVER_NOT_TRUSTED, {"additional_field": "12345"}),
+                expected_code=403,
+                expected_fields={
+                    "errcode": "M_SERVER_NOT_TRUSTED",
+                    "additional_field": "12345",
+                },
+            ),
+        ]
+    )
+    def test_spam_checker_check_event_for_spam(
+        self,
+        name: str,
+        value: Union[str, bool, Codes, Tuple[Codes, JsonDict]],
+        expected_code: int,
+        expected_fields: dict,
+    ) -> None:
+        class SpamCheck:
+            mock_return_value: Union[
+                str, bool, Codes, Tuple[Codes, JsonDict], bool
+            ] = "NOT_SPAM"
+            mock_content: Optional[JsonDict] = None
+
+            async def check_event_for_spam(
+                self,
+                event: synapse.events.EventBase,
+            ) -> Union[str, Codes, Tuple[Codes, JsonDict], bool]:
+                self.mock_content = event.content
+                return self.mock_return_value
+
+        spam_checker = SpamCheck()
+
+        self.hs.get_spam_checker()._check_event_for_spam_callbacks.append(
+            spam_checker.check_event_for_spam
+        )
+
+        # Inject `value` as mock_return_value
+        spam_checker.mock_return_value = value
+        path = "/rooms/%s/send/m.room.message/check_event_for_spam_%s" % (
+            urlparse.quote(self.room_id),
+            urlparse.quote(name),
+        )
+        body = "test-%s" % name
+        content = '{"body":"%s","msgtype":"m.text"}' % body
+        channel = self.make_request("PUT", path, content)
+
+        # Check that the callback has witnessed the correct event.
+        self.assertIsNotNone(spam_checker.mock_content)
+        if (
+            spam_checker.mock_content is not None
+        ):  # Checked just above, but mypy doesn't know about that.
+            self.assertEqual(
+                spam_checker.mock_content["body"], body, spam_checker.mock_content
+            )
+
+        # Check that we have the correct result.
+        self.assertEqual(expected_code, channel.code, msg=channel.result["body"])
+        for expected_key, expected_value in expected_fields.items():
+            self.assertEqual(
+                channel.json_body.get(expected_key, None),
+                expected_value,
+                "Field %s absent or invalid " % expected_key,
+            )
+

 class RoomPowerLevelOverridesTestCase(RoomBase):
    """Tests that the power levels can be overridden with server config."""
@ -1858,6 +2007,90 @@ class PublicRoomsRestrictedTestCase(unittest.HomeserverTestCase):
        self.assertEqual(channel.code, 200, channel.result)


+class PublicRoomsRoomTypeFilterTestCase(unittest.HomeserverTestCase):
+
+    servlets = [
+        synapse.rest.admin.register_servlets_for_client_rest_resource,
+        room.register_servlets,
+        login.register_servlets,
+    ]
+
+    def make_homeserver(self, reactor: MemoryReactor, clock: Clock) -> HomeServer:
+
+        config = self.default_config()
+        config["allow_public_rooms_without_auth"] = True
+        config["experimental_features"] = {"msc3827_enabled": True}
+        self.hs = self.setup_test_homeserver(config=config)
+        self.url = b"/_matrix/client/r0/publicRooms"
+
+        return self.hs
+
+    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
+        user = self.register_user("alice", "pass")
+        self.token = self.login(user, "pass")
+
+        # Create a room
+        self.helper.create_room_as(
+            user,
+            is_public=True,
+            extra_content={"visibility": "public"},
+            tok=self.token,
+        )
+        # Create a space
+        self.helper.create_room_as(
+            user,
+            is_public=True,
+            extra_content={
+                "visibility": "public",
+                "creation_content": {EventContentFields.ROOM_TYPE: RoomTypes.SPACE},
+            },
+            tok=self.token,
+        )
+
+    def make_public_rooms_request(
+        self, room_types: Union[List[Union[str, None]], None]
+    ) -> Tuple[List[Dict[str, Any]], int]:
+        channel = self.make_request(
+            "POST",
+            self.url,
+            {"filter": {PublicRoomsFilterFields.ROOM_TYPES: room_types}},
+            self.token,
+        )
+        chunk = channel.json_body["chunk"]
+        count = channel.json_body["total_room_count_estimate"]
+
+        self.assertEqual(len(chunk), count)
+
+        return chunk, count
+
+    def test_returns_both_rooms_and_spaces_if_no_filter(self) -> None:
+        chunk, count = self.make_public_rooms_request(None)
+
+        self.assertEqual(count, 2)
+
+    def test_returns_only_rooms_based_on_filter(self) -> None:
+        chunk, count = self.make_public_rooms_request([None])
+
+        self.assertEqual(count, 1)
+        self.assertEqual(chunk[0].get("org.matrix.msc3827.room_type", None), None)
+
+    def test_returns_only_space_based_on_filter(self) -> None:
+        chunk, count = self.make_public_rooms_request(["m.space"])
+
+        self.assertEqual(count, 1)
+        self.assertEqual(chunk[0].get("org.matrix.msc3827.room_type", None), "m.space")
+
+    def test_returns_both_rooms_and_space_based_on_filter(self) -> None:
+        chunk, count = self.make_public_rooms_request(["m.space", None])
+
+        self.assertEqual(count, 2)
+
+    def test_returns_both_rooms_and_spaces_if_array_is_empty(self) -> None:
+        chunk, count = self.make_public_rooms_request([])
+
+        self.assertEqual(count, 2)
+
+
 class PublicRoomsTestRemoteSearchFallbackTestCase(unittest.HomeserverTestCase):
    """Test that we correctly fallback to local filtering if a remote server
    doesn't support search.
@ -1882,7 +2115,7 @@ class PublicRoomsTestRemoteSearchFallbackTestCase(unittest.HomeserverTestCase):
        "Simple test for searching rooms over federation"
        self.federation_client.get_public_rooms.return_value = make_awaitable({})  # type: ignore[attr-defined]

-        search_filter = {"generic_search_term": "foobar"}
+        search_filter = {PublicRoomsFilterFields.GENERIC_SEARCH_TERM: "foobar"}

        channel = self.make_request(
            "POST",
@ -1911,7 +2144,7 @@ class PublicRoomsTestRemoteSearchFallbackTestCase(unittest.HomeserverTestCase):
            make_awaitable({}),
        )

-        search_filter = {"generic_search_term": "foobar"}
+        search_filter = {PublicRoomsFilterFields.GENERIC_SEARCH_TERM: "foobar"}

        channel = self.make_request(
            "POST",
@ -3149,7 +3382,8 @@ class ThreepidInviteTestCase(unittest.HomeserverTestCase):
        make_invite_mock.assert_called_once()

        # Now change the return value of the callback to deny any invite and test that
-        # we can't send the invite.
+        # we can't send the invite. We pick an arbitrary error code to be able to check
+        # that the same code has been returned
        mock.return_value = make_awaitable(Codes.CONSENT_NOT_GIVEN)
        channel = self.make_request(
            method="POST",
@ -3163,6 +3397,27 @@ class ThreepidInviteTestCase(unittest.HomeserverTestCase):
            access_token=self.tok,
        )
        self.assertEqual(channel.code, 403)
+        self.assertEqual(channel.json_body["errcode"], Codes.CONSENT_NOT_GIVEN)
+
+        # Also check that it stopped before calling _make_and_store_3pid_invite.
+        make_invite_mock.assert_called_once()
+
+        # Run variant with `Tuple[Codes, dict]`.
+        mock.return_value = make_awaitable((Codes.EXPIRED_ACCOUNT, {"field": "value"}))
+        channel = self.make_request(
+            method="POST",
+            path="/rooms/" + self.room_id + "/invite",
+            content={
+                "id_server": "example.com",
+                "id_access_token": "sometoken",
+                "medium": "email",
+                "address": email_to_invite,
+            },
+            access_token=self.tok,
+        )
+        self.assertEqual(channel.code, 403)
+        self.assertEqual(channel.json_body["errcode"], Codes.EXPIRED_ACCOUNT)
+        self.assertEqual(channel.json_body["field"], "value")

        # Also check that it stopped before calling _make_and_store_3pid_invite.
        make_invite_mock.assert_called_once()
--- a/tests/rest/client/utils.py
+++ b/tests/rest/client/utils.py
@ -41,6 +41,7 @@ from twisted.web.resource import Resource
 from twisted.web.server import Site

 from synapse.api.constants import Membership
+from synapse.api.errors import Codes
 from synapse.server import HomeServer
 from synapse.types import JsonDict

@ -171,6 +172,8 @@ class RestHelper:
        expect_code: int = HTTPStatus.OK,
        tok: Optional[str] = None,
        appservice_user_id: Optional[str] = None,
+        expect_errcode: Optional[Codes] = None,
+        expect_additional_fields: Optional[dict] = None,
    ) -> None:
        self.change_membership(
            room=room,
@ -180,6 +183,8 @@ class RestHelper:
            appservice_user_id=appservice_user_id,
            membership=Membership.JOIN,
            expect_code=expect_code,
+            expect_errcode=expect_errcode,
+            expect_additional_fields=expect_additional_fields,
        )

    def knock(
@ -263,6 +268,7 @@ class RestHelper:
        appservice_user_id: Optional[str] = None,
        expect_code: int = HTTPStatus.OK,
        expect_errcode: Optional[str] = None,
+        expect_additional_fields: Optional[dict] = None,
    ) -> None:
        """
        Send a membership state event into a room.
@ -323,6 +329,21 @@ class RestHelper:
                channel.result["body"],
            )

+        if expect_additional_fields is not None:
+            for expect_key, expect_value in expect_additional_fields.items():
+                assert expect_key in channel.json_body, "Expected field %s, got %s" % (
+                    expect_key,
+                    channel.json_body,
+                )
+                assert (
+                    channel.json_body[expect_key] == expect_value
+                ), "Expected: %s at %s, got: %s, resp: %s" % (
+                    expect_value,
+                    expect_key,
+                    channel.json_body[expect_key],
+                    channel.json_body,
+                )
+
        self.auth_user_id = temp_id

    def send(
--- a/tests/rest/media/v1/test_media_storage.py
+++ b/tests/rest/media/v1/test_media_storage.py
@ -23,11 +23,13 @@ from urllib import parse
 import attr
 from parameterized import parameterized, parameterized_class
 from PIL import Image as Image
+from typing_extensions import Literal

 from twisted.internet import defer
 from twisted.internet.defer import Deferred
 from twisted.test.proto_helpers import MemoryReactor

+from synapse.api.errors import Codes
 from synapse.events import EventBase
 from synapse.events.spamcheck import load_legacy_spam_checkers
 from synapse.logging.context import make_deferred_yieldable
@ -570,9 +572,11 @@ class MediaRepoTests(unittest.HomeserverTestCase):
        )


-class TestSpamChecker:
+class TestSpamCheckerLegacy:
    """A spam checker module that rejects all media that includes the bytes
    `evil`.
+
+    Uses the legacy Spam-Checker API.
    """

    def __init__(self, config: Dict[str, Any], api: ModuleApi) -> None:
@ -613,7 +617,7 @@ class TestSpamChecker:
        return b"evil" in buf.getvalue()


-class SpamCheckerTestCase(unittest.HomeserverTestCase):
+class SpamCheckerTestCaseLegacy(unittest.HomeserverTestCase):
    servlets = [
        login.register_servlets,
        admin.register_servlets,
@ -637,7 +641,8 @@ class SpamCheckerTestCase(unittest.HomeserverTestCase):
            {
                "spam_checker": [
                    {
-                        "module": TestSpamChecker.__module__ + ".TestSpamChecker",
+                        "module": TestSpamCheckerLegacy.__module__
+                        + ".TestSpamCheckerLegacy",
                        "config": {},
                    }
                ]
@ -662,3 +667,62 @@ class SpamCheckerTestCase(unittest.HomeserverTestCase):
        self.helper.upload_media(
            self.upload_resource, data, tok=self.tok, expect_code=400
        )
+
+
+EVIL_DATA = b"Some evil data"
+EVIL_DATA_EXPERIMENT = b"Some evil data to trigger the experimental tuple API"
+
+
+class SpamCheckerTestCase(unittest.HomeserverTestCase):
+    servlets = [
+        login.register_servlets,
+        admin.register_servlets,
+    ]
+
+    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
+        self.user = self.register_user("user", "pass")
+        self.tok = self.login("user", "pass")
+
+        # Allow for uploading and downloading to/from the media repo
+        self.media_repo = hs.get_media_repository_resource()
+        self.download_resource = self.media_repo.children[b"download"]
+        self.upload_resource = self.media_repo.children[b"upload"]
+
+        hs.get_module_api().register_spam_checker_callbacks(
+            check_media_file_for_spam=self.check_media_file_for_spam
+        )
+
+    async def check_media_file_for_spam(
+        self, file_wrapper: ReadableFileWrapper, file_info: FileInfo
+    ) -> Union[Codes, Literal["NOT_SPAM"]]:
+        buf = BytesIO()
+        await file_wrapper.write_chunks_to(buf.write)
+
+        if buf.getvalue() == EVIL_DATA:
+            return Codes.FORBIDDEN
+        elif buf.getvalue() == EVIL_DATA_EXPERIMENT:
+            return (Codes.FORBIDDEN, {})
+        else:
+            return "NOT_SPAM"
+
+    def test_upload_innocent(self) -> None:
+        """Attempt to upload some innocent data that should be allowed."""
+        self.helper.upload_media(
+            self.upload_resource, SMALL_PNG, tok=self.tok, expect_code=200
+        )
+
+    def test_upload_ban(self) -> None:
+        """Attempt to upload some data that includes bytes "evil", which should
+        get rejected by the spam checker.
+        """
+
+        self.helper.upload_media(
+            self.upload_resource, EVIL_DATA, tok=self.tok, expect_code=400
+        )
+
+        self.helper.upload_media(
+            self.upload_resource,
+            EVIL_DATA_EXPERIMENT,
+            tok=self.tok,
+            expect_code=400,
+        )
--- a/Show more
+++ b/Show more