fix: missing events not being processed properly

packages/federation-sdk/src/services/event.service.ts

@@ -154,10 +154,7 @@ export class EventService {
 		}
 	}
 
-	private async processIncomingPDUs(
-		origin: string,
-		pdus: Pdu[],
-	): Promise<void> {
+	async processIncomingPDUs(origin: string, pdus: Pdu[]): Promise<void> {
 		// organize events by room id
 		const eventsByRoomId = new Map<string, Pdu[]>();
 		for (const event of pdus) {
@@ -265,7 +262,17 @@ export class EventService {
 			throw new Error('M_MISSING_SIGNATURES_OR_HASHES');
 		}
 
-		await checkSignAndHashes(event, origin, getPublicKeyFromServer);
+		let originToValidateSignatures = origin;
+
+		// If the event does not have a signature for the origin server,
+		// but has a signature for our server, we validate using our server name.
+		// This happens on sendJoin process, where the join event is signed by our server,
+		// but the origin is the remote server since it just returns the event as we sent it.
+		if (!event.signatures[origin] && event.signatures[this.configService.serverName]) {
+			originToValidateSignatures = this.configService.serverName;
+		}
+
+		await checkSignAndHashes(event, originToValidateSignatures, getPublicKeyFromServer);
 	}
 
 	private async processIncomingEDUs(edus: BaseEDU[]): Promise<void> {

packages/federation-sdk/src/services/missing-event.service.ts

@@ -50,7 +50,7 @@ export class MissingEventService {
 				this.logger.debug(`Persisting fetched missing event ${eventId}`);
 
 				// TODO is there anything else we need to do with missing dependencies from received event?
-				await this.stateService.persistEvent(event);
+				await this.eventService.processIncomingPDUs(origin, [event]);
 			}
 		} catch (err: unknown) {
 			this.logger.error(

packages/federation-sdk/src/services/room.service.ts

@@ -987,7 +987,7 @@ export class RoomService {
 		);
 
 		// try to persist the join event now, should succeed with state in place
-		await stateService.persistStateEvent(joinEventFinal);
+		await this.eventService.processIncomingPDUs(residentServer || joinEventFinal.origin, [joinEventFinal.event]);
 
 		if (joinEventFinal.rejected) {
 			throw new Error(joinEventFinal.rejectedReason);