Gradle Transitive Dependencies Question

This repository has been created as a reproduction case to support a Gradle forum question.

The crux of the question is:

Why doesn't Gradle download transitive dependencies when a file extension e.g. @jar is specified on a dependency?

This is demonstrated as follows:

1. Clone this repository.
2. Run ./gradlew test. The task will fail with a compilation error because javaposse.jobdsl.dsl.JobManagement is not available on the test compilation classpath.
3. Uncomment line 59 in build.gradle
4. Run ./gradlew test again. This time compilation will succeed and the BasicSpec test will pass.
5. Help me understand why this happens?

Hypothesis

1. javaposse.jobdsl.dsl.JobManagement resides in the org.jenkins-ci.plugins:job-dsl-core dependency, which is a transitive dependency of the org.jenkins-ci.plugins:job-dsl dependency.
2. The packaging element in the org.jenkins-ci.plugins:job-dsl pom.xml is set to hpi. If we declare this dependency as testImplementation "org.jenkins-ci.plugins:job-dsl:${jobDslVersion}" then Gradle will also download all of its transitive dependencies (which include job-dsl-core) and will add them to the relevant classpath.
3. However, I specifically want the jar artefact of job-dsl, as it contains classes that I want to use. When the hpi artefact gets pulled in those classes are unavailable to me.
4. I can obtain the jar artefact of job-dsl by specifying @jar as the extension. When I do this Gradle downloads the jar artefact, however it also then no longer downloads any of the transitive dependencies.
5. The only solution I can think of is to then explicitly depend on each of the, now absent, transitive dependencies. However this feels wrong and brittle.
6. Question: Is there a way I can tell Gradle to download the job-dsl jar artefact and to also download all of its transitive dependencies?

Very grateful for any help on this one!

Solution

• The initial problem is demonstrated in commit ec26bbfcee8b8deac1ffee55b743ce8813d5ad22.
• The solution that I came up with in the end is in commit 147cb86cd2487b642275ac1d66174782ad8568e8. This was inspired from help received on the Gradle forum here