Android: Kotlin 2.3 compile error in RNGestureHandlerModule (rootViewTag vs getRootViewTag) #4042

Summary

When compiling the Android library with Kotlin 2.3.x (e.g. as required by other dependencies such as Stripe Android SDK), RNGestureHandlerModule.kt fails to compile in findRootHelperForViewAncestor:

Function invocation 'getRootViewTag()' expected

at the expression using it.rootView.rootViewTag next to a local variable also named rootViewTag.

Environment

• react-native-gesture-handler 2.30.1 (also reproducible on current 2.30.x line)
• Kotlin 2.3.0+ (project/toolchain aligned with RN 0.83 + libraries compiled with Kotlin 2.3 metadata)
• Android Gradle Plugin 8.12 (typical RN 0.83 setup)

Root cause

Inside findRootHelperForViewAncestor, the local val rootViewTag = ... shadows the synthetic Kotlin property rootViewTag on ReactRootView. The compiler then fails to resolve the property access on the left-hand side of the comparison (Kotlin 2.3 is stricter here than 2.1.x).

ReactRootView exposes the tag via getRootViewTag() in Java; the fix is to use an explicit receiver and call getRootViewTag() (or rename the local variable).

Suggested fix

synchronized(roots) {
  return roots.firstOrNull {
    val rv = it.rootView
    rv is ReactRootView && rv.getRootViewTag() == rootViewTag
  }
}

Workaround

Consumers can apply the one-line change locally (e.g. patch-package) until an upstream release includes the fix.

Related downstream context: projects that bump Kotlin to 2.3 for Stripe or other SDKs hit this as a hard compile failure on :react-native-gesture-handler:compileDebugKotlin.