Kotlin Multiplatform: a Java call to a Kotlin object links the commonMain expect instead of the platform actual #3033

What happens

When a Java file calls into a Kotlin Multiplatform object, the call now links to the expect declaration in commonMain instead of the actual in the platform source set. An expect declaration doesn't exist in JVM bytecode, so a Java caller can only ever reach the actual.

// lib/src/commonMain/kotlin/a/Util.kt
package a
expect object Util {
    fun go()
}

// lib/src/androidMain/kotlin/a/Util.kt
package a
actual object Util {
    @JvmStatic
    actual fun go() { println("android") }
}

// app/src/main/java/b/App.java
package b;
import a.Util;
class App { void run() { Util.go(); } }

• Expected: App.run calls lib/src/androidMain/kotlin/a/Util.kt: Util::go.
• Actual on main (60b0d7a): App.run calls lib/src/commonMain/kotlin/a/Util.kt: Util::go.

Regression

This changed with #3023, which made a Java call through an import reach the Kotlin class it names. Before that (01e0ac3), the same call linked to the androidMain actual. In a real project, JakeWharton/timber, Timber.plant(...) and Timber.tag(...) from the Java sample app moved from androidMain/.../Timber.kt to the commonMain expect class Timber. So did extends Timber.Tree.

Possible direction: when an import names a class that has both expect and actual declarations, a Java caller (and a platform source set's Kotlin caller) should prefer the actual in a source set that caller can see.

Found by indexing the same repos with the builds before and after the recent JVM resolution fixes and diffing the edges.

Edited 2026-10-29: added the environment, the native-kernel check and the related issues. The repro and the expected and actual results are unchanged.

Environment: Linux (WSL2), Node 22.23.2. Reproduced on main at 60b0d7a both with CODEGRAPH_KERNEL=0 and with the native kernel.

Related: this changed with #3023, which made a Java call through an import reach the Kotlin class it names. #1676 is a separate feature request for a Kotlin Multiplatform bridge.