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iOS: negative min value and 0 as maximum value turns maximum to 1 #780
Description
Environment
- react-native info output:
System:
OS: macOS 26.3
CPU: (12) arm64 Apple M2 Pro
Memory: 109.70 MB / 16.00 GB
Shell:
version: "5.9"
path: /bin/zsh
Binaries:
Node:
version: 20.19.5 // also tried node 24
path: /Users/.../.nvm/versions/node/v20.19.5/bin/node
npm:
version: 10.9.4
path: /Users/.../node_modules/.bin/npm
Watchman: Not Found
Managers:
CocoaPods:
version: 1.16.2
path: /opt/homebrew/bin/pod
SDKs:
iOS SDK:
Platforms:
- DriverKit 25.2
- iOS 26.2
- macOS 26.2
- tvOS 26.2
- visionOS 26.2
- watchOS 26.2
Android SDK: Not Found
IDEs:
Android Studio: 2025.1 AI-251.26094.121.2513.14007798
Xcode:
version: 26.3/17C529
path: /usr/bin/xcodebuild
Languages:
Java:
version: 17.0.17
path: /Users/.../Library/Java/JavaVirtualMachines/corretto-17.0.17/Contents/Home/bin/javac
Ruby:
version: 2.6.10
path: /usr/bin/ruby
npmPackages:
"@react-native-community/cli":
installed: 15.1.3
wanted: 15.1.3
react:
installed: 19.1.0
wanted: 19.1.0
react-native:
installed: 0.81.5
wanted: 0.81.5
react-native-macos: Not Found
npmGlobalPackages:
"*react-native*": Not Found
Android:
hermesEnabled: true
newArchEnabled: true
iOS:
hermesEnabled: true
newArchEnabled: true
Description
When creating a slider with minimumValue = -10 and maximumValue = 0, the application in android works as expected, but on iOS the maximumValue gets overwritten to 1.
Reproducible Demo
<Slider
value={-5}
minimumValue={-10}
maximumValue={0}
step={0.5}
onValueChange={(value) => {console.log('CURENTLY AT: ', value)}}
onSlidingComplete=={(value) => {console.log('COMPLETE AT: ', value)}}
tapToSeek={false}
/>
Using this slider the logs will show CURRENTLY AT 1 when sliding fully to the right on iOS and 0 on Android
My current workaround
I set maximum to 0.1 and for my business logic in onSlidingComplete I do Math.min(value, 0)
Activity
huytdps13400 commentedon Aug 26, 2026
I traced this on current
main, and the issue is specific to the Fabric prop-update boundary rather thanRNCSlider.setMaximumValueitself.Slider.tsxcorrectly forwards an explicitmaximumValue={0}. However,RNCSliderNativeComponent.tsdeclaresmaximumValue?: Double, so the generatedRNCSliderPropsdefault is0.RNCSliderComponentViewinitializes_propsfrom those default props, while UIKit'sUISliderstarts withmaximumValue == 1. On the first update for an explicit zero,oldScreenProps.maximumValueandnewScreenProps.maximumValueare both0, so the equality guard skips[slider setMaximumValue:0]and UIKit keeps1. A negative minimum does differ from the generated default, so it is applied, producing exactly the reported-10...1range. Android does not use this UIKit/default-props mismatch.There are two narrow fixes:
maximumValue?: WithDefault<Double, 1>, with the other numeric defaults made explicit as appropriate), orupdatePropscompareslider.maximumValuewithnewScreenProps.maximumValueso an initial native/default mismatch is corrected.I prefer the first because it aligns generated defaults across platforms and keeps old/new-prop diffing valid. The repository currently has JS tests but no native iOS unit-test target; a JS renderer test would pass before the fix because the zero is already forwarded correctly. Would maintainers prefer a codegen-schema regression for option 1, or an iOS fixture/manual regression for option 2? Once the expected test surface is confirmed, I can send the focused fix without adding a test that proves only the JS half.