A shorthand held in a variable overrides later longhands: `border: var(--v)` then `.b { border-color: red }` renders blue

Start in src/native/styles/calculate-props.ts, where delayed declarations are held and later resolved, and use the reproduction in src/__tests__/native/delayed-shorthand-cascade.test.tsx to trace the cascade. Run the supplied Jest test and check the kept-variable cases against the folded results. Done means later longhands retain precedence and the border and transition cases match the expected cascade.

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

A shorthand held in a variable the runtime keeps is resolved after every rule, so its longhands overwrite the ones a later rule writes: .a { --v: 1px solid blue; border: var(--v) } .b { border-color: red } on className="a b" renders borderColor: "blue", where CSS and the folded route give red.

border over 1px solid blue then .b { border-color: red; } (folded): {"borderWidth":1,"borderStyle":"solid","borderColor":"#f00"}
border over 1px solid blue then .b { border-color: red; } (kept): {"borderColor":"blue","borderWidth":1,"borderStyle":"solid"}
border over 1px solid blue then nothing (folded): {"borderWidth":1,"borderStyle":"solid","borderColor":"#00f"}
border over 1px solid blue then nothing (kept): {"borderWidth":1,"borderStyle":"solid","borderColor":"blue"}
transition over width 1s then .b { transition-property: opacity; } (folded): {"transitionProperty":["opacity"],"transitionDuration":[1000],"transitionDelay":[0],"transitionTimingFunction":"ease"}
transition over width 1s then .b { transition-property: opacity; } (kept): {"transitionProperty":["opacity"],"transition":["width",1000]}

Expected: the kept route renders borderColor red, as the folded one does. calculateProps (src/native/styles/calculate-props.ts) holds a delayed declaration's place with a placeholder at its own key, border, and resolves it only while that placeholder stands; a shorthand resolver returns other keys (ShortHandSymbol), which no placeholder guards, so the later rule's borderColor is overwritten when the delayed pass runs.

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 found

Steps to reproduce

1. Clone the reproducer branch, which is main at 2421ea7 with one file added, src/__tests__/native/delayed-shorthand-cascade.test.tsx, and install:

   git clone --branch repro/531-runtime-shorthand-overwrites-later-longhands https://github.com/YevheniiKotyrlo/react-native-css
   cd react-native-css
   yarn install
   

2. Run yarn jest src/__tests__/native/delayed-shorthand-cascade.test.tsx.

src/__tests__/native/delayed-shorthand-cascade.test.tsx:

// Run from a react-native-css checkout: copy to src/__tests__/native/delayed-shorthand-cascade.test.tsx, then `yarn jest` it.
import { StyleSheet } from "react-native";

import { render, screen } from "@testing-library/react-native";
import { View } from "react-native-css/components/View";
import { registerCSS, testID } from "react-native-css/jest";

jest.mock("../../native/reanimated", () => ({
  animatedComponentFamily: (component: unknown) => component,
}));

test.each([
  ["border", "1px solid blue", ".b { border-color: red; }"],
  ["border", "1px solid blue", ""],
  ["transition", "width 1s", ".b { transition-property: opacity; }"],
])("%s: var(--v) over %s, then %s", (property, value, later) => {
  for (const inlineVariables of [true, false]) {
    registerCSS(`.a { --v: ${value}; ${property}: var(--v); } ${later}`, inlineVariables ? {} : { inlineVariables: false });
    render(<View testID={testID} className="a b" />);
    console.log(`${property} over ${value} then ${later || "nothing"} (${inlineVariables ? "folded" : "kept"}): ${JSON.stringify(StyleSheet.flatten(screen.getByTestId(testID).props.style))}`);
    screen.unmount();
  }
});

Expected: the later longhand wins, as in CSS and on the folded route: borderColor: "red".

Actual: the shorthand held in the variable overrides it: borderColor: "blue".

  console.log
    border over 1px solid blue then .b { border-color: red; } (folded): {"borderWidth":1,"borderStyle":"solid","borderColor":"#f00"}
      at log (src/__tests__/native/delayed-shorthand-cascade.test.tsx:20:13)
  console.log
    border over 1px solid blue then .b { border-color: red; } (kept): {"borderColor":"blue","borderWidth":1,"borderStyle":"solid"}
      at log (src/__tests__/native/delayed-shorthand-cascade.test.tsx:20:13)
  console.log
    border over 1px solid blue then nothing (folded): {"borderWidth":1,"borderStyle":"solid","borderColor":"#00f"}
      at log (src/__tests__/native/delayed-shorthand-cascade.test.tsx:20:13)
  console.log
    border over 1px solid blue then nothing (kept): {"borderWidth":1,"borderStyle":"solid","borderColor":"blue"}
      at log (src/__tests__/native/delayed-shorthand-cascade.test.tsx:20:13)
  console.log
    transition over width 1s then .b { transition-property: opacity; } (folded): {"transitionProperty":["opacity"],"transitionDuration":[1000],"transitionDelay":[0],"transitionTimingFunction":"ease"}
      at log (src/__tests__/native/delayed-shorthand-cascade.test.tsx:20:13)
  console.log
    transition over width 1s then .b { transition-property: opacity; } (kept): {"transitionProperty":["opacity"],"transition":["width",1000]}
      at log (src/__tests__/native/delayed-shorthand-cascade.test.tsx:20:13)
PASS src/__tests__/native/delayed-shorthand-cascade.test.tsx
  √ border: var(--v) over 1px solid blue, then .b { border-color: red; } (36 ms)
  √ border: var(--v) over 1px solid blue, then  (5 ms)
  √ transition: var(--v) over width 1s, then .b { transition-property: opacity; } (3 ms)
Test Suites: 1 passed, 1 total
Tests:       3 passed, 3 total
Snapshots:   0 total
Time:        1.107 s, estimated 2 s
Ran all test suites matching /src\\__tests__\\native\\delayed-shorthand-cascade.test.tsx/i.

Reproducible example repository

https://github.com/YevheniiKotyrlo/react-native-css/tree/repro/531-runtime-shorthand-overwrites-later-longhands