Add a compile time only dependency in sbt

Question

I would like to add a dependency to an sbt project which is only used for compilation. Neither should it be on the runtime class path, nor should it be visible in any form i

Answer 1

You can create a custom dependency configuration for this (actually, this is getting so common when you use private macros in your project, I wish SBT provided one).

In build.sbt:

// a 'compileonly' configuation
ivyConfigurations += config("compileonly").hide

// some compileonly dependency
libraryDependencies += "commons-io" % "commons-io" % "2.4" % "compileonly"

// appending everything from 'compileonly' to unmanagedClasspath
unmanagedClasspath in Compile ++= 
  update.value.select(configurationFilter("compileonly"))

That dependency will not appear in the pom.xml generated by publish and friends.

There almost is such a configuration available: the provided configuration. Except that provided ends up in the pom.xml as a dependency with provided scope. Also, provided means "the runtime itself provides this at runtime", not "this is not needed at runtime".