Resolving multiple artifacts

resolve.scala

def fetchPIDE(version: Version)(implicit ec: ExecutionContext): Future[List[Path]] = {
  val repositories = Seq(Repository.ivy2Local, Repository.mavenCentral, Repository.sonatypeReleases)

  val files = coursier.Files(
    Seq("https://" -> new File(sys.props("user.home") + "/.libisabelle/cache")),
    () => sys.error("impossible")
  )

  val cachePolicy = Repository.CachePolicy.Default

  def resolve(identifier: String) = {
    val dependency =
      Dependency(
        Module(BuildInfo.organization, s"pide-${identifier}_${BuildInfo.scalaBinaryVersion}"),
        BuildInfo.version
      )
    Resolution(Set(dependency)).process.run(repositories).toScalaFuture.map { res =>
      if (!res.isDone)
        sys.error("not converged")
      else if (!res.errors.isEmpty)
        sys.error(s"errors: ${res.errors}")
      else
        res.artifacts.toSet
    }
  }

  val pideInterface = resolve("interface")
  val pideVersion = resolve(version.identifier)

  for {
    i <- pideInterface
    v <- pideVersion
    artifacts = v -- i
    res <- Future.traverse(artifacts.toList)(files.file(_, cachePolicy).run.toScalaFuture)
  }
  yield
    res.map(_.fold(sys.error, _.toPath))
}