Gradle jar modules that have no source code

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1

Hi,

I am using Gradle 8.2.1 and Java 17.

One of our project’s modules needs to rewrite a jar’s META-INF/MANIFEST.MF so that the rest of the project can use the modified jar artifact. However, the rest of the project refuses to compile against this module, and I strongly suspect it’s because the project is looking to compile against source files - which simply do not exist in this case.

The jar in question is kotlinx-coroutines-core-jvm, and we also need dependency substitution to work for the sake of any transitive dependencies:

configurations.configureEach {
    resolutionStrategy {
        dependencySubstitution {
            substitute module('org.jetbrains.kotlinx:kotlinx-coroutines-core-jvm') using project(':libs:kotlin-coroutines')
        }
    }
}

This therefore demands that project(':libs:kotlin-coroutines') provides the jar artifact instead of classes+resources.

Now it was my understanding that

project(':name')

was shorthand for

project(path: ':name', configuration: 'default')

And so I added this to libs/kotlin-coroutines/build.gradle:

configurations {
    'default' {
        attributes {
            attribute(LibraryElements.LIBRARY_ELEMENTS_ATTRIBUTE, objects.named(LibraryElements, LibraryElements.JAR))
        }
    }
}

However, projects that use

dependencies {
    implementation project(':libs:kotlin-coroutines')
}

are still failing to compile, although

dependencies {
   implementation project(path: ':libs:kotlin-coroutines', configuration: 'default')
}

does appear to work.

I’d be happy with this approach if it weren’t for the dependency substitution requirement :person_facepalming: Can anyone suggest a way to persuade project(':libs:kotlin-coroutines') to Do The Right Thing please?

Thanks,
Chris

P.S. This also seems to work:

dependencies {
    implementation(project(':libs:kotlin-coroutines')) {
        attributes {
            attribute(LibraryElements.LIBRARY_ELEMENTS_ATTRIBUTE, objects.named(LibraryElements, LibraryElements.JAR))
        }
    }
}

but is still incompatible with dependency substitution.

2

Hmm, am I along the right lines with:

resolutionStrategy {
    dependencySubstitution {
        substitute module('org.jetbrains.kotlinx:kotlinx-coroutines-core-jvm') using variant(project(':libs:kotlin-coroutines')) {
            attributes {
                attribute(LibraryElements.LIBRARY_ELEMENTS_ATTRIBUTE, objects.named(LibraryElements, LibraryElements.JAR))
            }
        }
    }
}

?