fix: depth calculation when add previous events (#275)

Author: debdutdeb

packages/room/src/manager/event-wrapper.spec.ts

@@ -1,6 +1,7 @@
 import { PersistentEventFactory } from './factory';
 
 import { describe, expect, it } from 'bun:test';
+import type { Pdu } from '../types/v3-11';
 import type { RoomVersion } from './type';
 
 function runTest(
@@ -366,4 +367,34 @@ describe('[EventWrapper] Redaction', () => {
 
 		// rest of the tests not yet part of normal standard
 	});
+
+	it('correctly calculate new depth', () => {
+		const e1 = PersistentEventFactory.createFromRawEvent(
+			{ depth: 1 } as Pdu,
+			'10',
+		);
+		const e2 = PersistentEventFactory.createFromRawEvent(
+			{ depth: 1 } as Pdu,
+			'10',
+		).addPrevEvents([e1]);
+		expect(e2.depth).toBe(2);
+		const e3 = PersistentEventFactory.createFromRawEvent(
+			{ depth: 5 } as Pdu,
+			'10',
+		);
+		e2.addPrevEvents([e3]);
+		expect(e2.depth).toBe(6);
+
+		const e4 = PersistentEventFactory.createFromRawEvent(
+			{ depth: 4 } as Pdu,
+			'10',
+		);
+		const e5 = PersistentEventFactory.createFromRawEvent(
+			{ depth: 7 } as Pdu,
+			'10',
+		);
+
+		e2.addPrevEvents([e5, e4]); // intentional out of order
+		expect(e2.depth).toBe(8);
+	});
 });

packages/room/src/manager/event-wrapper.ts

@@ -455,9 +455,12 @@ export abstract class PersistentEventBase<
 		for (const event of events) {
 			this.prevEventsIds.add(event.eventId);
 		}
-		if (this.rawEvent.depth <= events[events.length - 1].depth) {
-			this.rawEvent.depth = events[events.length - 1].depth + 1;
+		const deepestDepth =
+			events.sort((e1, e2) => e1.depth - e2.depth).pop()?.depth ?? 0;
+		if (this.rawEvent.depth <= deepestDepth) {
+			this.rawEvent.depth = deepestDepth + 1;
 		}
+
 		return this;
 	}