fix(federation): set room topic on creation of federated rooms

ee/packages/federation-matrix/src/FederationMatrix.ts

@@ -114,6 +114,10 @@ export class FederationMatrix extends ServiceClass implements IFederationMatrixS
 
 			this.logger.debug({ msg: 'Matrix room created', response: matrixRoomResult });
 
+			if (room.topic) {
+				await federationSDK.setRoomTopic(matrixRoomResult.room_id, matrixUserId, room.topic);
+			}
+
 			await Rooms.setAsFederated(room._id, { mrid: matrixRoomResult.room_id, origin: this.serverName });
 
 			// Members are NOT invited here - invites are sent via beforeAddUserToRoom callback.

ee/packages/federation-matrix/tests/end-to-end/room.spec.ts

@@ -1,4 +1,6 @@
 import type { IMessage, IUser } from '@rocket.chat/core-typings';
+import type { Room } from 'matrix-js-sdk';
+import { EventTimeline } from 'matrix-js-sdk';
 
 import {
 	createRoom,
@@ -713,6 +715,102 @@ import { SynapseClient } from '../helper/synapse-client';
 			});
 		});
 
+		describe('Create a room with a topic', () => {
+			describe('Create a federated room with a topic', () => {
+				let channelName: string;
+				let channelTopic: string;
+				let federatedChannel: any;
+
+				beforeAll(async () => {
+					channelName = `federated-channel-with-topic-${Date.now()}`;
+					channelTopic = 'This is a test topic for federation';
+
+					const createResponse = await createRoom({
+						type: 'p',
+						name: channelName,
+						members: [federationConfig.hs1.adminMatrixUserId],
+						extraData: {
+							federated: true,
+							topic: channelTopic,
+						},
+						config: rc1AdminRequestConfig,
+					});
+
+					federatedChannel = createResponse.body.group;
+
+					expect(federatedChannel).toHaveProperty('_id');
+					expect(federatedChannel).toHaveProperty('name', channelName);
+					expect(federatedChannel).toHaveProperty('t', 'p');
+					expect(federatedChannel).toHaveProperty('federated', true);
+
+					const acceptedRoomId = await hs1AdminApp.acceptInvitationForRoomName(channelName);
+					expect(acceptedRoomId).not.toBe('');
+				}, 10000);
+
+				it('should set the topic on the Rocket.Chat side', async () => {
+					// RC view: Verify the topic is set in Rocket.Chat
+					const roomInfo = await getRoomInfo(federatedChannel._id, rc1AdminRequestConfig);
+					expect(roomInfo.room).toHaveProperty('topic', channelTopic);
+				});
+
+				it('should set the topic on the Matrix side', async () => {
+					const hs1Room1 = (await hs1AdminApp.matrixClient.getRoom(federatedChannel.federation.mrid)) as Room;
+
+					expect(hs1Room1).toBeDefined();
+
+					const [topic] = hs1Room1.getLiveTimeline().getState(EventTimeline.FORWARDS)?.getStateEvents('m.room.topic') || [];
+
+					expect(topic.getContent().topic).toBe(channelTopic);
+				});
+			});
+
+			describe('Create a federated room without a topic', () => {
+				let channelName: string;
+				let federatedChannel: any;
+
+				beforeAll(async () => {
+					channelName = `federated-channel-no-topic-${Date.now()}`;
+
+					const createResponse = await createRoom({
+						type: 'p',
+						name: channelName,
+						members: [federationConfig.hs1.adminMatrixUserId],
+						extraData: {
+							federated: true,
+						},
+						config: rc1AdminRequestConfig,
+					});
+
+					federatedChannel = createResponse.body.group;
+
+					expect(federatedChannel).toHaveProperty('_id');
+					expect(federatedChannel).toHaveProperty('name', channelName);
+					expect(federatedChannel).toHaveProperty('t', 'p');
+					expect(federatedChannel).toHaveProperty('federated', true);
+					expect(federatedChannel).toHaveProperty('federation.mrid');
+
+					const acceptedRoomId = await hs1AdminApp.acceptInvitationForRoomName(channelName);
+					expect(acceptedRoomId).not.toBe('');
+				}, 10000);
+
+				it('should not set a topic on the Rocket.Chat side', async () => {
+					// RC view: Verify no topic is set in Rocket.Chat
+					const roomInfo = await getRoomInfo(federatedChannel._id, rc1AdminRequestConfig);
+					expect(roomInfo.room?.topic).toBeUndefined();
+				});
+
+				it('should not set a topic on the Matrix side', async () => {
+					const hs1Room1 = (await hs1AdminApp.matrixClient.getRoom(federatedChannel.federation.mrid)) as Room;
+
+					expect(hs1Room1).toBeDefined();
+
+					const [topic] = hs1Room1.getLiveTimeline().getState(EventTimeline.FORWARDS)?.getStateEvents('m.room.topic') || [];
+
+					expect(topic).toBeUndefined();
+				});
+			});
+		});
+
 		describe('Create a room on RC as private and federated, then invite users', () => {
 			describe('Go to the members list and', () => {
 				describe('Add a federated user', () => {