Dependency scope question

[Arthurm1]

Is there a Mill module dependency declaration equivalent to Gradle's implementation?

You can see in the link that implementation will include the dependency on the project's compile path but it will not be included transitively on any dependent project's compile path. It will be included on all the runtime paths.

An example of when I'd use this is if I'm writing a wrapper around a 3rd party library but don't want to expose any of the 3rd party library's API to any downstream project. This means any downstream project could only use my wrapper API.

[lefou]

Sound like implementation is a combination of compileOnly and runtimeOnly which would be equivalent to Mill's compileMvnDeps and runMvnDeps. To get a clue, you could look at how the dependencies are exported to a published pom.xml.

[Arthurm1]

I see - thanks. That's not too bad - only 1 additional declaration. I thought I might have to declare it as runtime on all downstream projects.

[lihaoyi]

Yes, using identical runMvnDeps and compileMvnDeps is the state of the art right now for "private" dependencies. We do this in the Mill codebase in a few places, e.g.

mill/libs/util/package.mill

Lines 20 to 21 in 11b3e88

	def compileMvnDeps = Seq(Deps.coursierJvm)
	def runMvnDeps = Seq(Deps.coursierJvm)

mill/libs/scalalib/package.mill

Lines 28 to 29 in 11b3e88

	def compileMvnDeps = Seq(Deps.sonatypeCentralClient)
	def runMvnDeps = Seq(Deps.sonatypeCentralClient)

mill/libs/javalib/package.mill

Lines 33 to 34 in 11b3e88

	def compileMvnDeps = Seq(Deps.sonatypeCentralClient)
	def runMvnDeps = Seq(Deps.sonatypeCentralClient)

[Arthurm1]

Thanks - that works for me for implementation.

Is there a way to mimic Gradle's compileOnlyApi? This is compile-only but is also transitive so downstream projects get it on their compile path but no projects get it on their runtime paths.

Also - are there moduleDeps equivalents for all of these? E.g. compileModuleDeps runModuleDeps?

Or can you refer to a module somehow under the various mvnDeps declarations? This is appealing to me - then there wouldn't be a need for the moduleDeps section. That's if module names were always distinct from maven dependency names

[lefou]

compileOnlyApi sounds like a mechanism that is only working when downstream projects also use Gradle. It can't be mapped to current Maven specs and is not portable.