[cortinico]

Summary:

Update Kotlin from 2.3.21 to 2.4.21 in the Gradle plugin, ReactAndroid, and the HelloWorld Android sample. This updates build tooling only; no React Native runtime or public API is changed. Keep the Gradle plugin API target at Kotlin 2.1 for compatibility. Kotlin 2.4 reports a deprecation warning for that older API target. Suppress only DEPRECATED_LANGUAGE_VERSION for now, while keeping all other Kotlin warnings as errors; remove the suppression in RN 0.90. Remove two redundant Robolectric REALISTIC annotations (Robolectric documents that mode as the default) to avoid deprecated enum usage in Kotlin unit tests.

Changelog:

[ANDROID] [CHANGED] - Update the Kotlin compiler and Gradle plugin to 2.4.21

Test Plan:

• cd private/helloworld/android && REACT_NATIVE_DOWNLOADS_DIR=/Users/ncor/git/react-native/packages/react-native/ReactAndroid/build/downloads JAVA_TOOL_OPTIONS='-Djava.io.tmpdir=/private/tmp -Dhttps.proxyHost=localhost -Dhttps.proxyPort=10054 -Dhttp.proxyHost=localhost -Dhttp.proxyPort=10054' ./gradlew -p /Users/ncor/git/react-native/packages/react-native --include-build /Users/ncor/git/react-native/packages/gradle-plugin :packages:react-native:ReactAndroid:testDebugUnitTest --tests com.facebook.react.views.text.TextDecorationStyleTest --tests com.facebook.react.views.text.TextLayoutManagerPixelWidthTest -x :packages:react-native:ReactAndroid:hermes-engine:buildHermesC -PenableWarningsAsErrors=true --console plain -Dhttps.proxyHost=localhost -Dhttps.proxyPort=10054 -Dhttp.proxyHost=localhost -Dhttp.proxyPort=10054 — passed. The unrelated local Hermes CMake prerequisite was excluded; CI builds Hermes normally.
• cd packages/gradle-plugin && JAVA_TOOL_OPTIONS=-Djava.io.tmpdir=/private/tmp ./gradlew build --rerun-tasks -PenableWarningsAsErrors=true --warning-mode all --console plain -Dhttps.proxyHost=localhost -Dhttps.proxyPort=10054 -Dhttp.proxyHost=localhost -Dhttp.proxyPort=10054 — passed (22 tasks executed, no Kotlin compiler warnings).
• cd packages/gradle-plugin && JAVA_TOOL_OPTIONS=-Djava.io.tmpdir=/private/tmp ./gradlew build --rerun-tasks --warning-mode all --console plain -Dhttps.proxyHost=localhost -Dhttps.proxyPort=10054 -Dhttp.proxyHost=localhost -Dhttp.proxyPort=10054 — passed. Reports the expected Kotlin API 2.1 deprecation warning.
• cd private/helloworld/android && REACT_NATIVE_DOWNLOADS_DIR=/Users/ncor/git/react-native/packages/react-native/ReactAndroid/build/downloads JAVA_TOOL_OPTIONS=-Djava.io.tmpdir=/private/tmp ./gradlew -p /Users/ncor/git/react-native/packages/react-native --include-build /Users/ncor/git/react-native/packages/gradle-plugin :packages:react-native:ReactAndroid:assembleDebug --warning-mode all --console plain -Dhttps.proxyHost=localhost -Dhttps.proxyPort=10054 -Dhttp.proxyHost=localhost -Dhttp.proxyPort=10054 — passed. No Kotlin compiler deprecations; existing Java deprecated-API usage and an unrelated CMake warning remain.
• git diff --check — passed.

Library-specific Android tooling compatibility has not been exhaustively tested.

Matching template draft PR: react-native-community/template#262

[cortinico]

The Kotlin 2.1 API target stays unchanged for compatibility. This PR suppresses only DEPRECATED_LANGUAGE_VERSION to keep build_android warnings-as-errors enabled; the suppression should be removed in RN 0.90 when the API target is updated.

[github-actions]

Visual regression

1 visual difference(s) at 3879a12b34fa. Visual differences need maintainer approval. Review the report, then apply visual-change-approved.

ios button/default-styling/default: Changed, 38223 px (1.533%)

Expected and Captured

Expected	Captured

[cortinico]

Once this lands this other PR also needs merging:

• [Android] Bump Kotlin to 2.4.21 react-native-community/template#262