From cabae397c61ed18b2eae9c84811028857f1a72a8 Mon Sep 17 00:00:00 2001
From: Samuel Susla <samuelsusla@meta.com>
Date: Fri, 5 Jan 2024 15:13:53 -0800
Subject: [PATCH] add nullptr check to avoid crash in
 RCTScrollViewComponentView (#42156)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/42156

changelog: [internal]

Add a missing nullptr check to prevent crash if called after component was reused

Reviewed By: fkgozali

Differential Revision: D52572807

fbshipit-source-id: 1b5b26996e562abbcb986865299e02df20b58043
---
 .../ComponentViews/ScrollView/RCTScrollViewComponentView.mm   | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/packages/react-native/React/Fabric/Mounting/ComponentViews/ScrollView/RCTScrollViewComponentView.mm b/packages/react-native/React/Fabric/Mounting/ComponentViews/ScrollView/RCTScrollViewComponentView.mm
index b164cc3d6acd12..7bc047c740ab33 100644
--- a/packages/react-native/React/Fabric/Mounting/ComponentViews/ScrollView/RCTScrollViewComponentView.mm
+++ b/packages/react-native/React/Fabric/Mounting/ComponentViews/ScrollView/RCTScrollViewComponentView.mm
@@ -471,6 +471,10 @@ - (BOOL)scrollViewShouldScrollToTop:(UIScrollView *)scrollView
 
 - (void)scrollViewDidScrollToTop:(UIScrollView *)scrollView
 {
+  if (!_eventEmitter) {
+    return;
+  }
+
   _isUserTriggeredScrolling = NO;
   static_cast<const ScrollViewEventEmitter &>(*_eventEmitter).onScrollToTop([self _scrollViewMetrics]);
   [self _updateStateWithContentOffset];