From a28ede2f72c88f63d13979f8ec90b93b321dcdf3 Mon Sep 17 00:00:00 2001
From: Ajay Bura <32841439+ajbura@users.noreply.github.com>
Date: Sun, 14 Aug 2022 15:07:15 +0530
Subject: [PATCH] Fix undetectable race condition in open timeline

---
 src/matrix/room/BaseRoom.js | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/matrix/room/BaseRoom.js b/src/matrix/room/BaseRoom.js
index 21b8e93d..09e74d39 100644
--- a/src/matrix/room/BaseRoom.js
+++ b/src/matrix/room/BaseRoom.js
@@ -47,6 +47,7 @@ export class BaseRoom extends EventEmitter {
         this._fragmentIdComparer = new FragmentIdComparer([]);
         this._emitCollectionChange = emitCollectionChange;
         this._timeline = null;
+        this._openTimelinePromise = null;
         this._user = user;
         this._changedMembersDuringSync = null;
         this._memberList = null;
@@ -542,7 +543,8 @@ export class BaseRoom extends EventEmitter {
 
     /** @public */
     openTimeline(log = null) {
-        return this._platform.logger.wrapOrRun(log, "open timeline", async log => {
+        if (this._openTimelinePromise) return this._openTimelinePromise;
+        this._openTimelinePromise = this._platform.logger.wrapOrRun(log, "open timeline", async log => {
             log.set("id", this.id);
             if (this._timeline) {
                 throw new Error("not dealing with load race here for now");
@@ -554,6 +556,7 @@ export class BaseRoom extends EventEmitter {
                 pendingEvents: this._getPendingEvents(),
                 closeCallback: () => {
                     this._timeline = null;
+                    this._openTimelinePromise = null;
                     if (this._roomEncryption) {
                         this._roomEncryption.notifyTimelineClosed();
                     }
@@ -575,6 +578,7 @@ export class BaseRoom extends EventEmitter {
             }
             return this._timeline;
         });
+        return this._openTimelinePromise;
     }
 
     /* allow subclasses to provide an observable list with pending events when opening the timeline */