fix: color scheme in appearance state after setting it to unspecified

[ismarbesic]

Summary:

Fixed the value of the color scheme in the appearance state after setting it to unspecified when state updates. The issue is described here #54959. This is a regression from #53397 and should be reproducible from 0.82 and higher. The useColorScheme() hook will return "unspecified" when you change the appearance from system color (dark or light) to system which breaks many apps using the value to determine whether to use dark/light mode colors.

Changelog:

[GENERAL] [FIXED] - Fix color scheme in appearance state after setting it to unspecified

Test Plan:

1. Run the reproducer app in the issue - use dark mode when launching the app, press "change to dark" and then "change to system". The hook will return "unspecified" although the correct behavior should be dark.
2. Apply the changes in this PR.
3. The correct behavior should be seen.

[oleksandr-dziuban]

Hello @facebook-github-bot

Can this be merged as RN v0.83.2 patch fix?

Seems like a huge regression issue which blocks teams to migrate to RN 0.83

Thanks a lot

[astrahov]

// 0.83.1
Appearance.setColorScheme('unspecified')

// iOS Log:
Invalid UIUserInterfaceStyle 'unspecified'. should be one of: (
    dark,
    light
)

[meta-codesync]

@cortinico has imported this pull request. If you are a Meta employee, you can view this in D92391594.

[cortinico]

/rebase

[react-native-bot]

This pull request was successfully merged by @ismarbesic in 08d1764

^{When will my fix make it into a release? | How to file a pick request?}

[danielma]

The official CHANGELOG says that this change was included in 0.83.2, but the npmjs tarball doesn't actually include it.

Repro

curl -O https://registry.npmjs.org/react-native/-/react-native-0.83.2.tgz
tar -xzf react-native-0.83.2.tgz -C .
sed -n 96,105p package/Libraries/Utilities/Appearance.js

Will output

export function setColorScheme(colorScheme: ColorSchemeName): void {
  const state = getState();
  const {NativeAppearance} = state;
  if (NativeAppearance != null) {
    NativeAppearance.setColorScheme(colorScheme);
    state.appearance = {
      colorScheme,
    };
  }
}

Which is the code from before this fix was merged

[JustJoostNL]

Yup, I also installed v0.83.2 specifically for this fix, but I discovered it wasn't actually included weirdly.

[julian-dueck]

The official CHANGELOG says that this change was included in 0.83.2, but the npmjs tarball doesn't actually include it.

Repro

curl -O https://registry.npmjs.org/react-native/-/react-native-0.83.2.tgz
tar -xzf react-native-0.83.2.tgz -C .
sed -n 96,105p package/Libraries/Utilities/Appearance.js

Will output

export function setColorScheme(colorScheme: ColorSchemeName): void {
  const state = getState();
  const {NativeAppearance} = state;
  if (NativeAppearance != null) {
    NativeAppearance.setColorScheme(colorScheme);
    state.appearance = {
      colorScheme,
    };
  }
}

Which is the code from before this fix was merged

@cortinico

[react-native-bot]

This pull request was successfully merged by @ismarbesic in c338d19

^{When will my fix make it into a release? | How to file a pick request?}