From ab8f3ff3e9e6445fa9961467e965792908d4c2bd Mon Sep 17 00:00:00 2001
From: Dawid <dawid.malecki21@gmail.com>
Date: Thu, 10 Oct 2024 06:37:28 -0700
Subject: [PATCH] fix: vertical scroll views are detected as horizontals
 (#46836)

Summary:
There is a numerical issue that causes vertical scroll view to be considered as the horizontal one and leads to problems described [here](https://github.com/facebook/react-native/issues/46592). The problem is no longer visible after checking if the scroll view is horizontal with float equality.

~~I am not sure if it also happens on Android, so I am leaving it as a draft for now.~~

Fixes https://github.com/facebook/react-native/issues/46592

## Changelog:

[IOS] [FIXED] - check if scroll view is horizontal with float equality.

<!-- Help reviewers and the release process by writing your own changelog entry.

Pick one each for the category and type tags:

[IOS] [FIXED] - fixed scroll view

For more details, see:
https://reactnative.dev/contributing/changelogs-in-pull-requests

Pull Request resolved: https://github.com/facebook/react-native/pull/46836

Test Plan: Tested on the repro provided in the above issue.

Reviewed By: rshest

Differential Revision: D64114476

Pulled By: cortinico

fbshipit-source-id: a5048e1403c4bb675d32928937d6411cfb12fd51
---
 .../ComponentViews/ScrollView/RCTEnhancedScrollView.mm        | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/react-native/React/Fabric/Mounting/ComponentViews/ScrollView/RCTEnhancedScrollView.mm b/packages/react-native/React/Fabric/Mounting/ComponentViews/ScrollView/RCTEnhancedScrollView.mm
index 93af874f451c58..2d884a73641683 100644
--- a/packages/react-native/React/Fabric/Mounting/ComponentViews/ScrollView/RCTEnhancedScrollView.mm
+++ b/packages/react-native/React/Fabric/Mounting/ComponentViews/ScrollView/RCTEnhancedScrollView.mm
@@ -7,6 +7,7 @@
 
 #import "RCTEnhancedScrollView.h"
 #import <React/RCTUtils.h>
+#import <react/utils/FloatComparison.h>
 
 @interface RCTEnhancedScrollView () <UIScrollViewDelegate>
 @end
@@ -261,7 +262,8 @@ - (void)scrollViewWillEndDragging:(UIScrollView *)scrollView
 
 - (BOOL)isHorizontal:(UIScrollView *)scrollView
 {
-  return scrollView.contentSize.width > self.frame.size.width;
+  return !facebook::react::floatEquality(scrollView.contentSize.width, self.frame.size.width) &&
+      scrollView.contentSize.width > self.frame.size.width;
 }
 
 @end