Send the `m.room.create` stripped event with invites (support MSC1772). (#9966)

MSC1772 specifies the m.room.create event should be sent as part
of the invite_state. This was done optionally behind an experimental
flag, but is now done by default due to MSC1772 being approved.

5 files changed, 34 insertions, 5 deletions

diff --git a/UPGRADE.rst b/UPGRADE.rst
index e921e0c08a..606e357b6e 100644
--- a/UPGRADE.rst
+++ b/UPGRADE.rst
@@ -85,6 +85,35 @@ for example:
      wget https://packages.matrix.org/debian/pool/main/m/matrix-synapse-py3/matrix-synapse-py3_1.3.0+stretch1_amd64.deb
      dpkg -i matrix-synapse-py3_1.3.0+stretch1_amd64.deb
 
+Upgrading to v1.34.0
+====================
+
+`room_invite_state_types` configuration setting
+-----------------------------------------------
+
+The ``room_invite_state_types`` configuration setting has been deprecated and
+replaced with ``room_prejoin_state``. See the `sample configuration file <https://github.com/matrix-org/synapse/blob/v1.34.0/docs/sample_config.yaml#L1515>`_.
+
+If you have set ``room_invite_state_types`` to the default value you should simply
+remove it from your configuration file. The default value used to be:
+
+.. code:: yaml
+
+   room_invite_state_types:
+      - "m.room.join_rules"
+      - "m.room.canonical_alias"
+      - "m.room.avatar"
+      - "m.room.encryption"
+      - "m.room.name"
+
+If you have customised this value by adding addition state types, you should
+remove ``room_invite_state_types`` and configure ``additional_event_types`` with
+your customisations.
+
+If you have customised this value by removing state types, you should rename
+``room_invite_state_types`` to ``additional_event_types``, and set
+``disable_default_event_types`` to ``true``.
+
 Upgrading to v1.33.0
 ====================
 
diff --git a/changelog.d/9915.feature b/changelog.d/9915.feature
index 832916cb01..7b81faabea 100644
--- a/changelog.d/9915.feature
+++ b/changelog.d/9915.feature
@@ -1 +1 @@
-Support stable identifiers from [MSC1772](https://github.com/matrix-org/matrix-doc/pull/1772).
+Support stable identifiers for [MSC1772](https://github.com/matrix-org/matrix-doc/pull/1772) Spaces. `m.space.child` events will now be taken into account when populating the experimental spaces summary response. Please see `UPGRADE.rst` if you have customised `room_invite_state_types` in your configuration.
\ No newline at end of file
diff --git a/changelog.d/9966.feature b/changelog.d/9966.feature
new file mode 100644
index 0000000000..7b81faabea
--- /dev/null
+++ b/changelog.d/9966.feature
@@ -0,0 +1 @@
+Support stable identifiers for [MSC1772](https://github.com/matrix-org/matrix-doc/pull/1772) Spaces. `m.space.child` events will now be taken into account when populating the experimental spaces summary response. Please see `UPGRADE.rst` if you have customised `room_invite_state_types` in your configuration.
\ No newline at end of file
diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml
index 7cf222d356..67ad57b1aa 100644
--- a/docs/sample_config.yaml
+++ b/docs/sample_config.yaml
@@ -1521,6 +1521,7 @@ room_prejoin_state:
    # - m.room.avatar
    # - m.room.encryption
    # - m.room.name
+   # - m.room.create
    #
    # Uncomment the following to disable these defaults (so that only the event
    # types listed in 'additional_event_types' are shared). Defaults to 'false'.
diff --git a/synapse/config/api.py b/synapse/config/api.py
index 55c038c0c4..b18044f982 100644
--- a/synapse/config/api.py
+++ b/synapse/config/api.py
@@ -88,10 +88,6 @@ class ApiConfig(Config):
         if not room_prejoin_state_config.get("disable_default_event_types"):
             yield from _DEFAULT_PREJOIN_STATE_TYPES
 
-            if self.spaces_enabled:
-                # MSC1772 suggests adding m.room.create to the prejoin state
-                yield EventTypes.Create
-
         yield from room_prejoin_state_config.get("additional_event_types", [])
 
 
@@ -109,6 +105,8 @@ _DEFAULT_PREJOIN_STATE_TYPES = [
     EventTypes.RoomAvatar,
     EventTypes.RoomEncryption,
     EventTypes.Name,
+    # Per MSC1772.
+    EventTypes.Create,
 ]