Quarkus ArC complains about a split package when the package combines Java and Kotlin in quarkusDev

[rodcheater]

Describe the bug

I’m using quarkus.index-dependency to add the beans from a library dependency to the Jandex index. Some of the packages contain both Java and Kotlin code. Running the application in dev mode emits a build warning about split packages; for example:

2025-06-20 15:16:16,605 WARN  [io.qua.arc.dep.SplitPackageProcessor] (build-11) Detected a split package usage which is considered a bad practice and should be avoided. Following packages were detected in multiple archives: 
- "org.acme.lib" found in [org.acme.lib:lib:1.0.0-SNAPSHOT]

Expected behavior

Packages containing both Java and Kotlin code are not considered split packages.

Actual behavior

A warning about split packages is emitted.

How to Reproduce?

Reproducer: quarkus-reproducer.zip

Steps to reproduce

1. ./gradlew quarkusDev

Expected result

No warning about split packages are emitted.

Actual result

A warning about split packages is emitted.

Output of uname -a or ver

Darwin Rods-MacBook-Pro.local 24.5.0 Darwin Kernel Version 24.5.0: Tue Apr 22 19:52:00 PDT 2025; root:xnu-11417.121.6~2/RELEASE_ARM64_T6031 arm64

Output of java -version

openjdk version "21.0.7" 2025-04-15 OpenJDK Runtime Environment Homebrew (build 21.0.7) OpenJDK 64-Bit Server VM Homebrew (build 21.0.7, mixed mode, sharing)

Quarkus version or git rev

3.23.4

Build tool (ie. output of mvnw --version or gradlew --version)

Gradle 8.9

Additional information

No response

[quarkus-bot]

/cc @Ladicek (arc), @geoand (kotlin), @manovotn (arc), @mkouba (arc)

[Ladicek]

This is an effect of how Gradle compiles Java and Kotlin code separately. I added an extra debug print to SplitPackageProcessor and here's what I got:

2025-06-20 09:41:48,221 WARN  [io.qua.arc.dep.SplitPackageProcessor] (build-38) org.acme.lib:
2025-06-20 09:41:48,221 WARN  [io.qua.arc.dep.SplitPackageProcessor] (build-38) - [paths: /home/lthon/tmp/quarkus-reproducer/lib/build/classes/java/main;]
2025-06-20 09:41:48,221 WARN  [io.qua.arc.dep.SplitPackageProcessor] (build-38) - [paths: /home/lthon/tmp/quarkus-reproducer/lib/build/classes/kotlin/main;]

[rodcheater]

Sure is. 🙂

[geoand]

I know it's hacky, but wouldn't it make sense to check for this specific scenario, as it's terribly uncommon?

[Ladicek]

I personally think that in Kotlin projects, a decent chunk of them are in fact mixed Java/Kotlin projects, so this probably isn't totally uncommon. I don't remember exactly how the check works, but I recall we figure out there's a split package because there's multiple sources, and proceed to fill the set of artifacts. We should be able to check that if the set of artifacts in fact only has 1 element and not print the warning in that case.

[geoand]

Sorry, I meant it's NOT terribly uncommon :)

[geoand]

@rodcheater in your reproducer how would I configure Gradle to use Quarkus built from main (version 999-SNAPSHOT)? I tried the usual ways I know of, but due to some Gradle specific thing I am not aware of, I couldn't get it to work.

[rodcheater]

@geoand In settings.gradle set the Quarkus version to 999-SNAPSHOT and add mavenLocal() before mavenCentral() in the set of repositories in dependencyResolutionManagement. (I’ve already got Maven local in the plugin repositories for some reason.)

[geoand]

I tried that and it didn't work, but I'll give it another shot

[geoand]

I am getting

* What went wrong:
A problem occurred configuring project ':app'.
> Failed to notify project evaluation listener.
   > 'java.lang.String org.gradle.api.artifacts.ProjectDependency.getPath()'

I any case if you want to try what I have in mind, here is a draft