ScrollView snapToInterval/snapToOffsets not working when the scrollView width is a float number in IOS.

[hiyuki]

Description

ScrollView snapToInterval/snapToOffsets not working when the scrollView width is a float number in IOS, because isHorizontal method in RCTEnhancedScrollView return a unexpected result when the width is a float.

- (BOOL)isHorizontal:(UIScrollView *)scrollView
{
  return scrollView.contentSize.width > self.frame.size.width;
}

In my reproducer: https://snack.expo.dev/@hiyuki/scrollview-snaptointerval-bug, when i set scrollView's width with a integer, such as 100, snapToInterval/snapToOffsets works fine, but when i set the width with a float number, such as 100.3, snapToInterval/snapToOffsets does't work.

Steps to reproduce

1. open the reproducer link: https://snack.expo.dev/@hiyuki/scrollview-snaptointerval-bug
2. execute it with expo go in a IOS device
3. scroll the scrollView content vertically, snapToInterval/snapToOffsets does't work when touch up

React Native Version

0.76.5

Affected Platforms

Runtime - iOS

Output of npx react-native info

System:
  OS: macOS 14.3.1
  CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
  Memory: 1.77 GB / 16.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 18.17.1
    path: /usr/local/bin/node
  Yarn: Not Found
  npm:
    version: 9.8.1
    path: /usr/local/bin/npm
  Watchman:
    version: 2024.01.22.00
    path: /usr/local/bin/watchman
Managers:
  CocoaPods:
    version: 1.15.2
    path: /usr/local/bin/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 23.4
      - iOS 17.4
      - macOS 14.4
      - tvOS 17.4
      - visionOS 1.1
      - watchOS 10.4
  Android SDK:
    API Levels:
      - "34"
      - "35"
    Build Tools:
      - 33.0.1
      - 34.0.0
      - 35.0.0
    System Images:
      - android-34 | Intel x86_64 Atom
      - android-34 | Google APIs Intel x86_64 Atom
    Android NDK: Not Found
IDEs:
  Android Studio: 2024.1 AI-241.18034.62.2412.12266719
  Xcode:
    version: 15.3/15E204a
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.12
    path: /usr/bin/javac
  Ruby:
    version: 2.6.10
    path: /usr/bin/ruby
npmPackages:
  "@react-native-community/cli":
    installed: 15.0.0-alpha.2
    wanted: 15.0.0-alpha.2
  react:
    installed: 18.3.1
    wanted: 18.3.1
  react-native:
    installed: 0.76.5
    wanted: ^0.76.5
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: true
iOS:
  hermesEnabled: true
  newArchEnabled: true

Stacktrace or Logs

no crash

Reproducer

https://snack.expo.dev/@hiyuki/scrollview-snaptointerval-bug

Screenshots and Videos

set ScrollView's width with 100.3, snapToInterval/snapToOffsets does't work.

63_1735194854.mp4

set ScrollView's width with 100, snapToInterval/snapToOffsets works fine.

64_1735194855.mp4

[react-native-bot]

Tip

Newer version available: You are on a supported minor version, but it looks like there's a newer patch available - 0.76.5. Please upgrade to the highest patch for your minor or latest and verify if the issue persists (alternatively, create a new project and repro the issue in it). If it does not repro, please let us know so we can close out this issue. This helps us ensure we are looking at issues that still exist in the most recent releases.

[react-native-bot]

Tip

Newer version available: You are on a supported minor version, but it looks like there's a newer patch available - undefined. Please upgrade to the highest patch for your minor or latest and verify if the issue persists (alternatively, create a new project and repro the issue in it). If it does not repro, please let us know so we can close out this issue. This helps us ensure we are looking at issues that still exist in the most recent releases.

[princektripathi]

@shubhamguptadream11, I have validated the repro, please update the label.
This seems to behaving oddly in iOS when decimal width is provided for ScrollView.

[sbuggay]

I was not able to repro this locally in vanilla RN, but was in Expo.

[hiyuki]

I met this problem in the newest vanilla RN(0.76.5) too, providing repro with expo just for convenient.

[sbuggay]

Thanks @hiyuki , do you have a vanilla RN reproducer repo you can share? I'm unable to repro it.

[hiyuki]

Thanks @hiyuki , do you have a vanilla RN reproducer repo you can share? I'm unable to repro it.

Yes, here it is, same as expo repro:

1. git clone https://github.com/hiyuki/RN-ScrollView-Reproducer.git
2. npm install
3. cd ios & pod install
4. cd .. & npm run ios

Expected result, snapToInterval works :

Simulator.Screen.Recording.-.iPhone.15.Pro.-.2025-01-06.at.19.52.25.mp4

Unexpected result, snapToInterval does't work:

Simulator.Screen.Recording.-.iPhone.15.Pro.-.2025-01-06.at.19.52.52.mp4