Incompatible with Kotlin 2.4.0: ClassCastException in StructuredCoroutinesCompilerPluginRegistrar (ProjectExtensionDescriptor removed, KT-83341)

[kdroidFilter]

Summary

The compiler plugin (latest 1.0.0) is incompatible with Kotlin 2.4.0. Any compilation with the plugin applied fails during FIR extension registration.

Stacktrace

java.lang.ClassCastException: class org.jetbrains.kotlin.fir.extensions.FirExtensionRegistrarAdapter$Companion cannot be cast to class org.jetbrains.kotlin.extensions.ProjectExtensionDescriptor
    at io.github.santimattius.structured.compiler.StructuredCoroutinesCompilerPluginRegistrar.registerExtensions(StructuredCoroutinesCompilerPluginRegistrar.kt:101)
    at org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment$Companion.registerExtensionsFromPlugins$org_jetbrains_kotlin_cli_base(KotlinCoreEnvironment.kt:758)
    ...

Cause

Kotlin 2.4.0 removed/changed the ProjectExtensionDescriptor-based FIR extension registration mechanism (see KT-83341). FirExtensionRegistrarAdapter.Companion no longer extends ProjectExtensionDescriptor, so the cast in registerExtensions throws.

The published structured-coroutines-compiler:1.0.0 POM still declares org.jetbrains.kotlin:kotlin-stdlib:2.3.20, confirming it builds against Kotlin 2.3.x.

Environment

• structured-coroutines: 1.0.0
• Kotlin: 2.4.0

Request

Please publish a release built against Kotlin 2.4.0 with the FIR extension registration migrated to the new API. For reference, skydoves/compose-stability-analyzer hit the identical issue and fixed it in its 0.9.0 release.