MSC4311: invites and knocks should contain the create event

changelog.d/19722.feature

@@ -0,0 +1 @@
+Partial [MSC4311](https://github.com/matrix-org/matrix-spec-proposals/pull/4311) implementation: `m.room.create` is now a required part of stripped `invite_state`/`knock_state` . Contributed by @FrenchGithubUser @Famedly.

synapse/config/api.py

@@ -48,6 +48,9 @@ def _get_prejoin_state_entries(
         self, config: JsonDict
     ) -> Iterable[tuple[str, str | None]]:
         """Get the event types and state keys to include in the prejoin state."""
+        # MSC4311: the create event must always be included in invite/knock state.
+        yield EventTypes.Create, ""
+
         room_prejoin_state_config = config.get("room_prejoin_state") or {}
 
         # backwards-compatibility support for room_invite_state_types

tests/config/test_api.py

@@ -5,7 +5,6 @@
 from synapse.config import ConfigError
 from synapse.config._base import RootConfig
 from synapse.config.api import ApiConfig
-from synapse.types.state import StateFilter
 
 DEFAULT_PREJOIN_STATE_PAIRS = {
     ("m.room.join_rules", ""),
@@ -38,7 +37,11 @@ def test_disable_default_event_types(self) -> None:
     disable_default_event_types: true
         """
         )
-        self.assertEqual(config.room_prejoin_state, StateFilter.none())
+        # MSC4311: m.room.create is always included even when defaults are disabled
+        self.assertEqual(
+            set(config.room_prejoin_state.concrete_types()),
+            {("m.room.create", "")},
+        )
 
     def test_event_without_state_key(self) -> None:
         config = self.read_config(
@@ -50,7 +53,11 @@ def test_event_without_state_key(self) -> None:
         """
         )
         self.assertEqual(config.room_prejoin_state.wildcard_types(), ["foo"])
-        self.assertEqual(config.room_prejoin_state.concrete_types(), [])
+        # MSC4311: m.room.create is always included
+        self.assertEqual(
+            set(config.room_prejoin_state.concrete_types()),
+            {("m.room.create", "")},
+        )
 
     def test_event_with_specific_state_key(self) -> None:
         config = self.read_config(
@@ -62,9 +69,10 @@ def test_event_with_specific_state_key(self) -> None:
         """
         )
         self.assertFalse(config.room_prejoin_state.has_wildcards())
+        # MSC4311: m.room.create is always included
         self.assertEqual(
             set(config.room_prejoin_state.concrete_types()),
-            {("foo", "bar")},
+            {("foo", "bar"), ("m.room.create", "")},
         )
 
     def test_repeated_event_with_specific_state_key(self) -> None:
@@ -78,9 +86,10 @@ def test_repeated_event_with_specific_state_key(self) -> None:
         """
         )
         self.assertFalse(config.room_prejoin_state.has_wildcards())
+        # MSC4311: m.room.create is always included
         self.assertEqual(
             set(config.room_prejoin_state.concrete_types()),
-            {("foo", "bar"), ("foo", "baz")},
+            {("foo", "bar"), ("foo", "baz"), ("m.room.create", "")},
         )
 
     def test_no_specific_state_key_overrides_specific_state_key(self) -> None:
@@ -94,7 +103,11 @@ def test_no_specific_state_key_overrides_specific_state_key(self) -> None:
         """
         )
         self.assertEqual(config.room_prejoin_state.wildcard_types(), ["foo"])
-        self.assertEqual(config.room_prejoin_state.concrete_types(), [])
+        # MSC4311: m.room.create is always included
+        self.assertEqual(
+            set(config.room_prejoin_state.concrete_types()),
+            {("m.room.create", "")},
+        )
 
         config = self.read_config(
             """
@@ -106,7 +119,11 @@ def test_no_specific_state_key_overrides_specific_state_key(self) -> None:
         """
         )
         self.assertEqual(config.room_prejoin_state.wildcard_types(), ["foo"])
-        self.assertEqual(config.room_prejoin_state.concrete_types(), [])
+        # MSC4311: m.room.create is always included
+        self.assertEqual(
+            set(config.room_prejoin_state.concrete_types()),
+            {("m.room.create", "")},
+        )
 
     def test_bad_event_type_entry_raises(self) -> None:
         with self.assertRaises(ConfigError):

tests/rest/client/test_sync.py

@@ -29,6 +29,7 @@
 from synapse.api.constants import (
     EventContentFields,
     EventTypes,
+    JoinRules,
     ReceiptTypes,
     RelationTypes,
 )
@@ -394,6 +395,69 @@ def test_knock_room_state(self) -> None:
         )
 
 
+class SyncCreateEventInPrejoinStateTestCase(unittest.HomeserverTestCase):
+    """MSC4311: Tests that m.room.create is present in invite_state and knock_state"""
+
+    servlets = [
+        synapse.rest.admin.register_servlets,
+        login.register_servlets,
+        room.register_servlets,
+        sync.register_servlets,
+        knock.register_servlets,
+    ]
+
+    def default_config(self) -> JsonDict:
+        config = super().default_config()
+        return config
+
+    def test_create_event_present_in_invite_state(self) -> None:
+        """m.room.create must appear in invite_state."""
+        inviter = self.register_user("inviter", "pass")
+        inviter_tok = self.login("inviter", "pass")
+        invitee = self.register_user("invitee", "pass")
+        invitee_tok = self.login("invitee", "pass")
+
+        room_id = self.helper.create_room_as(inviter, tok=inviter_tok)
+        self.helper.invite(room=room_id, src=inviter, targ=invitee, tok=inviter_tok)
+
+        channel = self.make_request("GET", "/sync", access_token=invitee_tok)
+        self.assertEqual(channel.code, 200, channel.json_body)
+
+        invite_state_events = channel.json_body["rooms"]["invite"][room_id][
+            "invite_state"
+        ]["events"]
+        event_types = {stripped_event["type"] for stripped_event in invite_state_events}
+        self.assertIn(EventTypes.Create, event_types)
+
+    def test_create_event_present_in_knock_state(self) -> None:
+        """m.room.create must appear in knock_state."""
+        host = self.register_user("host", "pass")
+        host_tok = self.login("host", "pass")
+        knocker = self.register_user("knocker", "pass")
+        knocker_tok = self.login("knocker", "pass")
+
+        room_id = self.helper.create_room_as(
+            host, is_public=False, room_version="7", tok=host_tok
+        )
+        self.helper.send_state(
+            room_id,
+            EventTypes.JoinRules,
+            {"join_rule": JoinRules.KNOCK},
+            tok=host_tok,
+        )
+
+        self.helper.knock(room_id, knocker, tok=knocker_tok)
+
+        channel = self.make_request("GET", "/sync", access_token=knocker_tok)
+        self.assertEqual(channel.code, 200, channel.json_body)
+
+        knock_state_events = channel.json_body["rooms"]["knock"][room_id][
+            "knock_state"
+        ]["events"]
+        event_types = {stripped_event["type"] for stripped_event in knock_state_events}
+        self.assertIn(EventTypes.Create, event_types)
+
+
 class UnreadMessagesTestCase(unittest.HomeserverTestCase):
     servlets = [
         synapse.rest.admin.register_servlets,