From b3523c320bbe17f0bae66f2900a80a286ce14cd8 Mon Sep 17 00:00:00 2001
From: Mikhail Aheichyk <mikhail.aheichyk@nordeck.net>
Date: Mon, 26 Feb 2024 09:21:30 +0300
Subject: [PATCH] Add event with m.reference relation to unknown parent to the
 timeline.

Signed-off-by: Mikhail Aheichyk <mikhail.aheichyk@nordeck.net>
---
 spec/unit/room.spec.ts | 19 +++++++++++++++++++
 src/models/room.ts     |  2 +-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/spec/unit/room.spec.ts b/spec/unit/room.spec.ts
index 4d64e4df54d..8b25416f3f3 100644
--- a/spec/unit/room.spec.ts
+++ b/spec/unit/room.spec.ts
@@ -3199,6 +3199,25 @@ describe("Room", function () {
             expect(room.eventShouldLiveIn(reply).shouldLiveInRoom).toBeTruthy();
             expect(room.eventShouldLiveIn(reply).shouldLiveInThread).toBeFalsy();
         });
+
+        it("an event with m.reference relation to unknown parent event should live in the main timeline only", async () => {
+            const event = utils.mkEvent({
+                event: true,
+                type: "org.example.child",
+                user: "@alice:example.org",
+                content: {
+                    "key": "value",
+                    "m.relates_to": {
+                        event_id: "$unknown-parent",
+                        rel_type: "m.reference",
+                    },
+                },
+                room: roomId,
+            });
+
+            expect(room.eventShouldLiveIn(event).shouldLiveInRoom).toBeTruthy();
+            expect(room.eventShouldLiveIn(event).shouldLiveInThread).toBeFalsy();
+        });
     });
 
     describe("getEventReadUpTo()", () => {
diff --git a/src/models/room.ts b/src/models/room.ts
index 67aea690756..e65aab07724 100644
--- a/src/models/room.ts
+++ b/src/models/room.ts
@@ -2197,7 +2197,7 @@ export class Room extends ReadReceipt<RoomEmittedEvents, RoomEventHandlerMap> {
         // Due to replies not being typical relations and being used as fallbacks for threads relations
         // If we bypass the if case above then we know we are not a thread, so if we are still a reply
         // then we know that we must be in the main timeline. Same goes if we have no associated parent event.
-        if (!parentEventId || !!event.replyEventId) {
+        if (!parentEventId || !!event.replyEventId || event.getRelation()?.rel_type === "m.reference") {
             return {
                 shouldLiveInRoom: true,
                 shouldLiveInThread: false,