Project dependencies not possible in Gradle Plugin development


I created a multi module project

|-> common-utils (applies plugin ‘java-library’ and contains groovy classes)
|-> myPlugin (applies ‘java-gradle-plugin’ and depends on common-utils)

Obviously the dependency of common-utils in myPlugin I wanted to add as project dependency.
But during compilation of myPlugin the classes from common-utils are not visible (“unable to resolve class”).

If I publish common-utils to my local .m2 and add it as artifact dependencies in myPlugin everything works fine.

What do I miss?

There is a documented limitation when using the java-library plugin in combination with the groovy plugin.