From 673e6c31625ded3f9215ec4cfbdefa09b1c97295 Mon Sep 17 00:00:00 2001
From: Travis Ralston <travpc@gmail.com>
Date: Wed, 27 Nov 2019 12:26:43 -0700
Subject: [PATCH] Don't assume that diffs will have an appropriate child node

Fixes https://github.com/vector-im/riot-web/issues/11497

This is a regression from react-sdk v1.5.0 where the diff feature was added in the first place. It only affects lists.
---
 src/utils/MessageDiffUtils.js | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/utils/MessageDiffUtils.js b/src/utils/MessageDiffUtils.js
index 78f3faa0c5..de0d8fdc89 100644
--- a/src/utils/MessageDiffUtils.js
+++ b/src/utils/MessageDiffUtils.js
@@ -77,6 +77,8 @@ function findRefNodes(root, route, isAddition) {
     const end = isAddition ? route.length - 1 : route.length;
     for (let i = 0; i < end; ++i) {
         refParentNode = refNode;
+        // Lists don't have appropriate child nodes we can use.
+        if (!refNode.childNodes[route[i]]) continue;
         refNode = refNode.childNodes[route[i]];
     }
     return {refNode, refParentNode};