From 828c51467ffa6d3c9d713a326e3f46518403d1f1 Mon Sep 17 00:00:00 2001
From: Travis Ralston <travpc@gmail.com>
Date: Fri, 5 Apr 2019 11:36:01 -0600
Subject: [PATCH] Refuse to set forwards pagination token on live timeline

Should fix the error seen in https://github.com/matrix-org/riot-web-rageshakes/issues/1389 (https://github.com/vector-im/riot-web/issues/8593)
---
 src/models/event-timeline-set.js | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/models/event-timeline-set.js b/src/models/event-timeline-set.js
index 9675f7300ed..6025b7d774f 100644
--- a/src/models/event-timeline-set.js
+++ b/src/models/event-timeline-set.js
@@ -446,6 +446,14 @@ EventTimelineSet.prototype.addEventsToTimeline = function(events, toStartOfTimel
     // new information, we update the pagination token for whatever
     // timeline we ended up on.
     if (lastEventWasNew || !didUpdate) {
+        if (direction === EventTimeline.FORWARDS && timeline === this._liveTimeline) {
+            console.warn({lastEventWasNew, didUpdate}); // for debugging
+            console.warn(
+                `Refusing to set forwards pagination token of live timeline ` +
+                `${timeline} to ${paginationToken}`,
+            );
+            return;
+        }
         timeline.setPaginationToken(paginationToken, direction);
     }
 };