Idiomatic way to run scapegoat on compile

[jjst]

What's the idiomatic way to run scapegoat automatically on compile? ie. I want sbt compile to run scapegoat.

I tried adding this in my build.sbt:

compile in Compile := (compile in Compile).dependsOn(scapegoat).value

This works, however, it compiles all classes twice - once in target/scala-2.11/scapegoat-classes and once in target/scala-2.11/classes. Is there a better way?

[morgen-peschke]

This is back-of-the-napkin converted from something similar we're using for another liner:

(compile in Compile) := Def.taskDyn {
  val c = (compile in Compile).value
  Def.task {
    (scapegoat in Compile).toTask("").value
    c
  }
}.value

(compile in Test) := Def.taskDyn {
  val c = (compile in Test).value
  Def.task {
    (scapegoat in Test).toTask("").value
    c
  }
}.value