Set Dependencies / Plugins versions depending on scalaVersion-CodePudding

I am trying to set different versions for the dependencies and plugins on my build.sbt script, depending the value of the scalaVersion on a crossCompiled project.

Here is a reduced and simplified representation of what I have so far:

scalaVersion := "2.11.12"
crossScalaVersions := Seq("2.11.12", "2.12.14")


val currentDependencies = Def.setting {
  scalaVersion.value match {
    case "2.11.12" => new {
      val circe         = "0.12.0-M3"
      val kindProjector = "0.10.3"
    }

    case "2.12.14" => new {
      val circe         = "0.14.1"
      val kindProjector = "0.13.2"
    }
  }
}

libraryDependencies   = Seq (
  "io.circe" %% "circe-core" % currentDependencies.value.circe
)

addCompilerPlugin(
  "org.typelevel" %% "kind-projector" % currentDependencies.value.kindProjector
)

The libraryDependencies part is correct, even though it would have been cleaner to not be forced to add the .value part.

Ideally I would have simply declared a Map(scalaV1 -> { dep1 -> v1}, scalaV2 -> { dep1 -> v2} )

But the problem I have is with regards to addCompilerPlugin, as it's not happening within a task or setting, I get the following error:

error: `value` can only be used within a task or setting macro, such as :=,  =,   =, Def.task, or Def.setting.

Is there a cleaner way to achieve what I'm trying to do? And how can I get the right dependency version depending on the scalaVersion for non tasks?

CodePudding user response：

Regarding the libraries, an approach that I've often seen in projects is to do it like this:

libraryDependencies   = {
      CrossVersion.partialVersion(scalaVersion.value) match {
        case Some((2, 12)) =>
          List("groupA" %% "libA" % "x.y.z", "groupB" %% "libB" % "x.y.z")
        case Some((2, 11)) =>
          List("groupA" %% "libA" % "x.y.z", ...)
        case _ =>
          Nil
      }
    }

Which should be transformable to something like this to match your expectation (not tested):

val myVersions: Map[Int, Map[String, String]] = Map(
  11 -> Map("libA" -> "x.y.z", "libB" -> "x.y.z"),
  12 -> Map("libA" -> "x.y.z", "libB" -> "x.y.z")
)

libraryDependencies   = {
      CrossVersion.partialVersion(scalaVersion.value) match {
        case Some((2, n)) =>
          List("groupA" %% "libA" % myVersions(n)("libA"), "groupB" %% "libB" % myVersions(n)("libB"))
        case _ =>
          Nil
      }
    }

Obviously this is just a draft on which the reader can iterate.

Regarding compiler plugin, a similar approach can be used by using the following syntax as replacement for addCompilerPlugin(dependency):

libraryDependencies  = compilerPlugin(dependency)

(Source: https://github.com/sbt/sbt/blob/2dad7ea76385261aa542b5e7410d50d19e1a496a/main/src/main/scala/sbt/Defaults.scala#L4317)