Support for room v11 as the default room version (#858)

---------

Signed-off-by: Thomas Traineau t.traineau@famedly.com

Author: FrenchGithubUser

federation/server_room.go

@@ -333,15 +333,20 @@ func InitialRoomEvents(roomVer gomatrixserverlib.RoomVersion, creator string) []
 			Type:     "m.room.create",
 			StateKey: b.Ptr(""),
 			Sender:   creator,
-			Content: map[string]interface{}{
-				"creator":      creator,
-				"room_version": roomVer,
-				// We have to add randomness to the create event, else if you create 2x v12+ rooms in the same millisecond
-				// they will get the same room ID, clobbering internal data structures and causing extremely confusing
-				// behaviour. By adding this entropy, we ensure that even if rooms are created in the same millisecond, their
-				// hashes will not be the same.
-				"complement_entropy": util.RandomString(18),
-			},
+			Content: func() map[string]interface{} {
+				content := map[string]interface{}{
+					"room_version": roomVer,
+					// We have to add randomness to the create event, else if you create 2x v12+ rooms in the same millisecond
+					// they will get the same room ID, clobbering internal data structures and causing extremely confusing
+					// behaviour. By adding this entropy, we ensure that even if rooms are created in the same millisecond, their
+					// hashes will not be the same.
+					"complement_entropy": util.RandomString(18),
+				}
+				if gomatrixserverlib.MustGetRoomVersion(gomatrixserverlib.RoomVersion(roomVer)).CreatorInCreateEvent() {
+					content["creator"] = creator
+				}
+				return content
+			}(),
 		},
 		{
 			Type:     "m.room.member",

go.mod

@@ -7,7 +7,7 @@ require (
 	github.com/docker/go-connections v0.6.0
 	github.com/gorilla/mux v1.8.1
 	github.com/matrix-org/gomatrix v0.0.0-20220926102614-ceba4d9f7530
-	github.com/matrix-org/gomatrixserverlib v0.0.0-20250813150445-9f5070a65744
+	github.com/matrix-org/gomatrixserverlib v0.0.0-20260506075950-c9c468727353
 	github.com/matrix-org/util v0.0.0-20221111132719-399730281e66
 	github.com/sirupsen/logrus v1.9.4
 	github.com/tidwall/gjson v1.18.0

go.sum

@@ -73,6 +73,8 @@ github.com/matrix-org/gomatrix v0.0.0-20220926102614-ceba4d9f7530 h1:kHKxCOLcHH8
 github.com/matrix-org/gomatrix v0.0.0-20220926102614-ceba4d9f7530/go.mod h1:/gBX06Kw0exX1HrwmoBibFA98yBk/jxKpGVeyQbff+s=
 github.com/matrix-org/gomatrixserverlib v0.0.0-20250813150445-9f5070a65744 h1:5GvC2FD9O/PhuyY95iJQdNYHbDioEhMWdeMP9maDUL8=
 github.com/matrix-org/gomatrixserverlib v0.0.0-20250813150445-9f5070a65744/go.mod h1:b6KVfDjXjA5Q7vhpOaMqIhFYvu5BuFVZixlNeTV/CLc=
+github.com/matrix-org/gomatrixserverlib v0.0.0-20260506075950-c9c468727353 h1:BdGU/8sF4ZaqGhfYN+eFEzc/whU4LpKvEDdM6i0Oqqs=
+github.com/matrix-org/gomatrixserverlib v0.0.0-20260506075950-c9c468727353/go.mod h1:b6KVfDjXjA5Q7vhpOaMqIhFYvu5BuFVZixlNeTV/CLc=
 github.com/matrix-org/util v0.0.0-20221111132719-399730281e66 h1:6z4KxomXSIGWqhHcfzExgkH3Z3UkIXry4ibJS4Aqz2Y=
 github.com/matrix-org/util v0.0.0-20221111132719-399730281e66/go.mod h1:iBI1foelCqA09JJgPV0FYz4qA5dUXYOxMi57FxKBdd4=
 github.com/miekg/dns v1.1.66 h1:FeZXOS3VCVsKnEAd+wBkjMC3D2K+ww66Cq3VnCINuJE=

tests/csapi/rooms_state_test.go

@@ -15,6 +15,7 @@ import (
 	"github.com/matrix-org/complement/helpers"
 	"github.com/matrix-org/complement/match"
 	"github.com/matrix-org/complement/must"
+	"github.com/matrix-org/gomatrixserverlib"
 )
 
 func TestRoomCreationReportsEventsToMyself(t *testing.T) {
@@ -26,6 +27,7 @@ func TestRoomCreationReportsEventsToMyself(t *testing.T) {
 		LocalpartSuffix: "bob",
 		Password:        "bobpassword",
 	})
+	defaultVer := alice.GetDefaultRoomVersion(t)
 	roomID := alice.MustCreateRoom(t, map[string]interface{}{})
 
 	t.Run("parallel", func(t *testing.T) {
@@ -38,7 +40,10 @@ func TestRoomCreationReportsEventsToMyself(t *testing.T) {
 					return false
 				}
 				must.Equal(t, ev.Get("sender").Str, alice.UserID, "wrong sender")
-				must.Equal(t, ev.Get("content").Get("creator").Str, alice.UserID, "wrong content.creator")
+				// The creator field was removed in room version 11 (MSC4239).
+				if gomatrixserverlib.MustGetRoomVersion(defaultVer).CreatorInCreateEvent() {
+					must.Equal(t, ev.Get("content").Get("creator").Str, alice.UserID, "wrong content.creator")
+				}
 				return true
 			}))
 		})

tests/federation_room_get_missing_events_test.go

@@ -497,6 +497,16 @@ func TestOutboundFederationEventSizeGetMissingEvents(t *testing.T) {
 	}).Methods("POST")
 
 	ver := alice.GetDefaultRoomVersion(t)
+	// This test crafts a "bad" event which state_key is 280 bytes but only 70
+	// codepoints.
+	//
+	// Room version 11 in Synapse switched from using codepoints to using
+	// bytes. Which means the 280-byte state_key would be rejected immediately.
+	// Use room version 10 in that case so the codepoint-based limit is in effect.
+	//
+	if gomatrixserverlib.MustGetRoomVersion(ver).StrictEventByteLimits() {
+		ver = gomatrixserverlib.RoomVersion("10")
+	}
 	charlie := srv.UserID("charlie")
 	room := srv.MustMakeRoom(t, ver, federation.InitialRoomEvents(ver, charlie))
 	roomAlias := srv.MakeAliasMapping("flibble", room.RoomID)