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An infinite rem, em or vw length skips the px clamp and reaches React Native as null #537
Description
Before submitting a new issue
- I tested using the latest version of the library, as the bug might be already fixed.
- I tested using a supported version of react native.
- I checked for possible duplicate issues, with possible answers.
Bug summary
parseLength's px branch clamps an infinite or overflowing length to a safe integer; the rem branch (length.value * inlineRem) and the em and vw descriptors do not. calc(infinity * 1rem) therefore reaches the style as Infinity, which a device bundle carries as null, where calc(infinity * 1px) gives the clamped length. Tailwind's rounded-full is calc(infinity * 1px), so the px form is the common one; a theme that scales it with rem meets this.
The px case passes; the others fail:
calc(infinity * 1px): {"borderRadius":9007199254740991}
calc(infinity * 1rem): {"borderRadius":null}
calc(infinity * 1em): {"borderRadius":null}
calc(infinity * 1vw): {"borderRadius":null}
Library version
main at 2421ea7 (0.0.0-nightly.2421ea7)
Environment info
System:
OS: Windows 11 10.0.26300
CPU: "(32) x64 AMD Ryzen 9 9950X3D 16-Core Processor "
Memory: 155.26 GB / 255.67 GB
Binaries:
Node:
version: 26.12.1
path: C:\Program Files\nodejs\node.EXE
Yarn:
version: 4.9.2
path: C:\Users\<user>\AppData\Roaming\npm\yarn.CMD
npm:
version: 12.2.1
path: C:\Program Files\nodejs\npm.CMD
Watchman: Not Found
SDKs:
Android SDK:
API Levels:
- "33"
- "35"
- "35"
- "35"
- "36"
- "37"
Build Tools:
- 35.0.0
- 36.0.0
- 36.1.0
- 37.0.0
System Images:
- android-26 | Google APIs Intel x86_64 Atom
- android-28 | Google APIs Intel x86_64 Atom
- android-29 | Google APIs Intel x86_64 Atom
- android-30 | Google APIs Intel x86_64 Atom
- android-31 | Google APIs Intel x86_64 Atom
- android-32 | Google APIs Intel x86_64 Atom
- android-33 | Google APIs Intel x86_64 Atom
- android-34 | Google APIs Intel x86_64 Atom
- android-35 | Google APIs Intel x86_64 Atom
- android-36.1 | Google Play Intel x86_64 Atom
- android-36.1 | Pre-Release 16 KB Page Size Google Play Intel x86_64 Atom
- android-37.0 | Google APIs Intel x86_64 Atom
Android NDK: Not Found
Windows SDK: Not Found
IDEs:
Android Studio: AI-262.9437.185.2621.16467767
Visual Studio: Not Found
Languages:
Java:
version: 17.0.20.1
path: C:\Program Files\Microsoft\jdk-17.0.20.101-hotspot\bin\javac.EXE
Ruby: Not Found
npmPackages:
"@react-native-community/cli": Not Found
react:
installed: 19.2.3
wanted: 19.2.3
react-native:
installed: 0.86.3
wanted: 0.86.3
react-native-windows: Not Found
npmGlobalPackages:
"*react-native*": Not Found
Android:
hermesEnabled: Not found
newArchEnabled: Not found
iOS:
hermesEnabled: Not found
newArchEnabled: Not foundSteps to reproduce
- Clone the reproducer branch, which is
mainat 2421ea7 with one file added,src/__tests__/native/infinite-relative-length.test.tsx, and install:git clone --branch repro/537-relative-lengths-skip-the-px-clamp https://github.com/YevheniiKotyrlo/react-native-css cd react-native-css yarn install - Run
yarn jest src/__tests__/native/infinite-relative-length.test.tsx.
src/__tests__/native/infinite-relative-length.test.tsx:
import { render, screen } from "@testing-library/react-native";
import { View } from "react-native-css/components/View";
import { registerCSS, testID } from "react-native-css/jest";
test.each(["1px", "1rem", "1em", "1vw"])(
"border-radius: var(--r) over an inlined --r: calc(infinity * %s) is a finite length",
(unit) => {
registerCSS(`.a { --r: calc(infinity * ${unit}); border-radius: var(--r); }`);
render(<View testID={testID} className="a" />);
const { style } = screen.getByTestId(testID).props;
console.log(`calc(infinity * ${unit}): ${JSON.stringify(style)}`);
expect(Number.isFinite(style?.borderRadius)).toBe(true);
},
);Expected: an infinite rem, em or vw length is clamped, as an infinite px length is.
Actual: it reaches the style as Infinity, which a device bundle carries as null.
The run's output on main at 2421ea7, Windows 11, Node 26.12.1
console.log
calc(infinity * 1px): {"borderRadius":9007199254740991}
at log (src/__tests__/native/infinite-relative-length.test.tsx:11:13)
console.log
calc(infinity * 1rem): {"borderRadius":null}
at log (src/__tests__/native/infinite-relative-length.test.tsx:11:13)
console.log
calc(infinity * 1em): {"borderRadius":null}
at log (src/__tests__/native/infinite-relative-length.test.tsx:11:13)
console.log
calc(infinity * 1vw): {"borderRadius":null}
at log (src/__tests__/native/infinite-relative-length.test.tsx:11:13)
FAIL src/__tests__/native/infinite-relative-length.test.tsx
√ border-radius: var(--r) over an inlined --r: calc(infinity * 1px) is a finite length (26 ms)
× border-radius: var(--r) over an inlined --r: calc(infinity * 1rem) is a finite length (6 ms)
× border-radius: var(--r) over an inlined --r: calc(infinity * 1em) is a finite length (2 ms)
× border-radius: var(--r) over an inlined --r: calc(infinity * 1vw) is a finite length (2 ms)
● border-radius: var(--r) over an inlined --r: calc(infinity * 1rem) is a finite length
expect(received).toBe(expected) // Object.is equality
Expected: true
Received: false
10 | const { style } = screen.getByTestId(testID).props;
11 | console.log(`calc(infinity * ${unit}): ${JSON.stringify(style)}`);
> 12 | expect(Number.isFinite(style?.borderRadius)).toBe(true);
| ^
13 | },
14 | );
15 |
at toBe (src/__tests__/native/infinite-relative-length.test.tsx:12:50)
● border-radius: var(--r) over an inlined --r: calc(infinity * 1em) is a finite length
expect(received).toBe(expected) // Object.is equality
Expected: true
Received: false
10 | const { style } = screen.getByTestId(testID).props;
11 | console.log(`calc(infinity * ${unit}): ${JSON.stringify(style)}`);
> 12 | expect(Number.isFinite(style?.borderRadius)).toBe(true);
| ^
13 | },
14 | );
15 |
at toBe (src/__tests__/native/infinite-relative-length.test.tsx:12:50)
● border-radius: var(--r) over an inlined --r: calc(infinity * 1vw) is a finite length
expect(received).toBe(expected) // Object.is equality
Expected: true
Received: false
10 | const { style } = screen.getByTestId(testID).props;
11 | console.log(`calc(infinity * ${unit}): ${JSON.stringify(style)}`);
> 12 | expect(Number.isFinite(style?.borderRadius)).toBe(true);
| ^
13 | },
14 | );
15 |
at toBe (src/__tests__/native/infinite-relative-length.test.tsx:12:50)
Test Suites: 1 failed, 1 total
Tests: 3 failed, 1 passed, 4 total
Snapshots: 0 total
Time: 1.094 s, estimated 2 s
Ran all test suites matching /src\\__tests__\\native\\infinite-relative-length.test.tsx/i.
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