[0.77.1] minimumFontScale doesn't work in New Arch

Description

Text props minimumFontScale doesn't work

Steps to reproduce

Install default app (npx @react-native-community/cli@latest init AwesomeProject)
Wrap Text to small View (width:100, height:100)
Add large text into text component
Set text props ( adjustsFontSizeToFit={true}
minimumFontScale={0.9}
numberOfLines={1} )
See result, text are small

React Native Version

0.77.1

Affected Platforms

Runtime - Android, Runtime - iOS

Areas

Fabric - The New Renderer

Output of `npx @react-native-community/cli info`

System:
  OS: macOS 15.1.1
  CPU: (12) arm64 Apple M3 Pro
  Memory: 238.53 MB / 18.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 22.11.0
    path: ~/.nvm/versions/node/v22.11.0/bin/node
  Yarn: Not Found
  npm:
    version: 10.9.0
    path: ~/.nvm/versions/node/v22.11.0/bin/npm
  Watchman:
    version: 2024.12.02.00
    path: /opt/homebrew/bin/watchman
Managers:
  CocoaPods:
    version: 1.16.2
    path: /opt/homebrew/opt/ruby/bin/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 24.1
      - iOS 18.1
      - macOS 15.1
      - tvOS 18.1
      - visionOS 2.1
      - watchOS 11.1
  Android SDK:
    API Levels:
      - "33"
      - "34"
      - "35"
    Build Tools:
      - 30.0.3
      - 33.0.0
      - 33.0.1
      - 34.0.0
      - 35.0.0
    System Images:
      - android-27 | ARM 64 v8a
      - android-35 | Google Play ARM 64 v8a
    Android NDK: Not Found
IDEs:
  Android Studio: 2024.3 AI-243.22562.218.2431.13114758
  Xcode:
    version: 16.1/16B40
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.13
    path: /usr/bin/javac
  Ruby:
    version: 3.3.6
    path: /opt/homebrew/opt/ruby/bin/ruby
npmPackages:
  "@react-native-community/cli":
    installed: 15.1.3
    wanted: 15.1.3
  react:
    installed: 18.3.1
    wanted: 18.3.1
  react-native:
    installed: 0.77.1
    wanted: ^0.77.1
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: true
iOS:
  hermesEnabled: true
  newArchEnabled: true

Stacktrace or Logs

Reproducer

https://snack.expo.dev/t1eb6mkjQgY6fAFeXjhPK

Screenshots and Videos

import { Text, SafeAreaView, StyleSheet, View } from 'react-native';

export default function App() {
  return (
    <SafeAreaView style={styles.container}>
      <View style={styles.wrapper}>
        <Text style={styles.paragraph} 
        adjustsFontSizeToFit={true}
        minimumFontScale={0.9}
        numberOfLines={1} >
          Change code in the editor and watch it change on your phone! Save to get a shareable url.
        </Text>
      </View>
    </SafeAreaView>
  );
}

const styles = StyleSheet.create({
  wrapper:{
    width:100,
    height:100,
    backgroundColor:'yellow'
  },
  container: {
    flex: 1,
    justifyContent: 'center',
    backgroundColor: '#ecf0f1',
    padding: 8,
    alignItems:'center'
  },
  paragraph: {
    margin: 24,
    fontSize: 18,
    fontWeight: 'bold',
    textAlign: 'center',
  },
});

Patch for fix (based on #43543)
react-native+0.77.1.patch

@DarkShtir

@DarkShtir Thanks for the issue, the reproducer and the patch. Have you perhaps tested it also with 0.78 and 0.79?

@cipolleschi

@cipolleschi Not yet. But I'll try to test this on 0.78 and 0.79 this weekend.

0.78 - works only IOS

Android doesn't work

Patch file

react-native+0.78.1.patch

And thanks janicduplessis for PR.

RN-0.79.0-rc.3 the same as 0.78. IOS - works, Android - none.
Need improve Android implementation
Patch file

react-native+0.79.0-rc.3.patch

Any updates?

@janicduplessis

react-native+0.79.2.patch

This patch fixed problems on stable RN 0.79.2
@janicduplessis @cipolleschi FYI

android rn0.79.2 not working

Any update on this? It's been a couple months with no word and I've had to disable every instance of this in my app because of this bug.

I'm having this issue on RN 0.80.1 not working on iOS and Android

I'm having this issue on RN 0.80.1 not working on iOS and Android

Same for me on IOS with 0.80.2 (New Architecture).
Not tested on Android.

Hey, just a bit confused: minimumFontScale is claimed as iOS props only. How does it work on Android? Is it a typo in the RN document, or did I misunderstand something?

Same for me on IOS AND Android with 0.81.4 (New Architecture).

Has there been any follow-up resolution to this issue? I'm encountering a similar problem on iOS version 0.77.1.

Is there a particular reason on why the patch in this thread haven't been upstreamed? I'm interested in taking it into the upstream if the author agrees.

when this will get solved

The below is posted by AI:

We just hit this in RN 0.86.0 on Fabric (Expo SDK 57). Confirming the bug + adding deeper root-cause analysis in case it helps whoever picks up the patch.

The actual failure point is minimumFontSize, not minimumFontScale itself. The bug spans three layers:

JS bridge (Libraries/Text/TextNativeComponent.js, validAttributes at lines 32-51): whitelists adjustsFontSizeToFit: true and minimumFontScale: true, but minimumFontSize is NOT in the whitelist — silently stripped at the bridge before reaching native.
C++ prop parser (ReactCommon/react/renderer/components/text/BaseParagraphProps.cpp:99-110): accepts both minimumFontScale AND minimumFontSize correctly. Both are stored on paragraphAttributes. No issue here.
iOS Fabric renderer (ReactCommon/react/renderer/textlayoutmanager/platform/ios/react/renderer/textlayoutmanager/RCTTextLayoutManager.mm:246-250): reads ONLY paragraphAttributes.minimumFontSize:
```
if (paragraphAttributes.adjustsFontSizeToFit) {
  CGFloat minimumFontSize = !isnan(paragraphAttributes.minimumFontSize) ? paragraphAttributes.minimumFontSize : 4.0;
  ...
}
```
When minimumFontSize is NaN (its default per ParagraphAttributes.h:70), the floor falls back to 4.0pt — which is the "keeps shrinking and shrinking" behavior users observe.

Android has the same shape: ReactTextView.java:64,198 uses mMinimumFontSize, populated from PA_KEY_MINIMUM_FONT_SIZE at ReactTextViewManager.kt:166-168. Would honor minimumFontSize if it arrived, but the bridge strips it identically to iOS.

iOS Paper (legacy) at Libraries/Text/Text/RCTTextShadowView.mm:236 is the only renderer that ever consulted minimumFontScale (multiplies _minimumFontScale * pointSize to derive minimumFontSize). That is why the prop historically "worked" on Paper iOS and nowhere else.

Net effect on Fabric (iOS and Android both): minimumFontScale is sent across the bridge, stored in C++, but never read by the renderer. minimumFontSize would be read and would work, but is stripped at the bridge before reaching native.

Minimal fix appears to be: add minimumFontSize: true to the validAttributes whitelist in TextNativeComponent.js. Once whitelisted, both iOS Fabric and Android Fabric would honor it without further changes. iOS Paper would continue to ignore it (it only reads minimumFontScale), but Paper is legacy.

The attached patch in the OP presumably does something similar. Hope this trace helps whoever reviews/lands it.

@cipolleschi

This issue perssist after more then a year. Any update on this @cipolleschi ?

Opened #58492 to fix this on both iOS and Android.

Fix `minimumFontScale` with `adjustsFontSizeToFit` in the New Archite…

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[0.77.1] minimumFontScale doesn't work in New Arch #50248

Description

Steps to reproduce

React Native Version

Affected Platforms

Areas

Output of `npx @react-native-community/cli info`

Stacktrace or Logs

Reproducer

Screenshots and Videos

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[0.77.1] minimumFontScale doesn't work in New Arch #50248

Description

Description

Steps to reproduce

React Native Version

Affected Platforms

Areas

Output of npx @react-native-community/cli info

Stacktrace or Logs

Reproducer

Screenshots and Videos

Activity

cipolleschi commented on Mar 26, 2025

DarkShtir commented on Mar 27, 2025

DarkShtir commented on Mar 27, 2025

DarkShtir commented on Mar 27, 2025

DarkShtir commented on Mar 27, 2025

DarkShtir commented on May 15, 2025

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conner1reimers commented on Sep 11, 2026

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Output of `npx @react-native-community/cli info`