Micronaut-core: Project fails to compile with Java 11 module, micronaut 1.2.3 and gradle 5.6.2

[chrispoulsen]

Hi, I'm trying to create a simple application with Java 11 and modules (module-info.java present). I'm having a hard time getting things to compile, as soon as I add:

annotationProcessor(platform("io.micronaut:micronaut-bom:$micronautVersion"))
annotationProcessor("io.micronaut:micronaut-inject-java")

to my gradle project, then the build fails with:

> Task :app.runner:compileJava FAILED                              

FAILURE: Build failed with an exception.                           

* What went wrong:                                                 
Execution failed for task ':app.runner:compileJava'.               
> java.lang.IllegalArgumentException: Unexpected element app.runner

The environment is Java 11, Gradle 5.6.2 and Micronaut 1.2.3. The --stacktrace and --debug options does not tell me anything useful.

The module is named "app.runner" - and if I change the module name, the error changes accordingly. If I add the lombok annotation processor instead, the build also seems to work.

I asked on Gitter and Graeme Rocher pointed me to a working project (https://github.com/weiqigao/micronaut-test-modules-issue).

That sample project is running on my system after adding a gradle 5.6.2 wrapper and still using Java 11.
However when I bump the micronaut version in the sample project from 1.1.0 to 1.2.3 the compileJava task fails again with the same "unexpected element " error as I see in my project.

[graemerocher]

This seems to be a Gradle bug to me. The stack trace is coming from Gradle's incremental compilation APIs

[graemerocher]

Reported https://github.com/gradle/gradle/issues/11059

[graemerocher]

I recommend using Maven until this is resolved in the Gradle side

[bademux]

It is interesting that build works with micronaut 1.2.1, but broken with 1.2.2
tested with cli-app-modular-java
by changing version for micronaut-bom

dependencyManagement {
    imports {
        mavenBom 'io.micronaut:micronaut-bom:1.2.1'
    }
}

[graemerocher]

Yes the root cause is that we added support for Gradle incremental annotation processors in 1.2.2 to remove warnings that Kotlin emits when non-incremental annotation processors are present.

However Gradle's support for incremental annotation processors is broken with modules. Hence https://github.com/gradle/gradle/issues/11059

[bademux]

Thanks for clarification!
Will it help to disable incremental annotation processors and is there easy way to do it?

[graemerocher]

not that I am aware, but we should probably make it possible. Dagger allows you to disable it.

[graemerocher]

Alternative is to switch to Maven

[msgilligan]

Alternative is to switch to Maven

Or stick with earlier versions of Micronaut.

[msgilligan]

I tried it with Gradle 6.0 RC2 and the same problem occurs.

Update: Still occurs with 6.0 RC3, as well.

[msgilligan]

@graemerocher says the Gradle issue is fixed in Gradle 6.1: https://github.com/gradle/gradle/issues/11059#issuecomment-580358363

I just updated my project that was failing with Micronaut 1.2.2+ to Gradle 6.1.1 and Micronaut 1.2.10 and it builds and runs successfully.