multi-project sbt build definition, involving dependent compiler and sbt plugins

build.sbt

val integrationTest = taskKey[Unit]("Executes integration tests.")

lazy val root = (project in file(".")).aggregate(simpleGraph, compilerPluginUnitTestLib, compilerPluginn, canveSbtPlugin, sbtPluginTestLib).enablePlugins(CrossPerProjectPlugin).settings(
  scalaVersion := "2.11.7",
  crossScalaVersions := Seq("2.10.4", "2.11.7"),
  publishArtifact := false, // no artifact to publish for the virtual root project
  integrationTest := (run in Compile in sbtPluginTestLib).value // not working: need to bounty http://stackoverflow.com/questions/33291071/invoking-a-subprojects-main-with-a-custom-task
)

lazy val simpleGraph = (project in file("simpleGraph"))
lazy val compilerPluginUnitTestLib = (project in file("compiler-plugin-unit-test-lib"))
lazy val compilerPluginn = (project in file("compiler-plugin")).settings(
  name := "compiler-plugin",
  organization := "canve",
  version := "0.0.1",
  isSnapshot := true, // to enable overwriting the existing artifact version
  scalaVersion := "2.11.7",
  crossScalaVersions := Seq("2.10.4", "2.11.7"),
  resolvers += "Sonatype OSS Snapshots" at "https://oss.sonatype.org/content/repositories/snapshots",
  
  libraryDependencies ++= Seq(
    "org.scala-lang" % "scala-compiler" % scalaVersion.value % "provided",
    "org.scala-lang" % "scala-library" % scalaVersion.value % "provided",
    "com.github.tototoshi" %% "scala-csv" % "1.2.2",
    //"com.github.tototoshi" %% "scala-csv" % "1.3.0-SNAPSHOT", // snapshot version might be causing sbt/ivy going nuts
    //"org.apache.tinkerpop" % "tinkergraph-gremlin" % "3.0.1-incubating",
    //"canve" %% "simple-graph" % "0.0.1",
    //"canve" %% "compiler-plugin-unit-test-lib" % "0.0.1" % "test",
    "com.lihaoyi" %% "utest" % "0.3.1" % "test"
  ),
  
  testFrameworks += new TestFramework("utest.runner.Framework"),

  /*
   * take care of including all non scala core library dependencies in the build artifact 
   */
  test in assembly := {},
  jarName in assembly := name.value + "_" + scalaVersion.value + "-" + version.value + "-assembly.jar",
  assemblyOption in assembly ~= { _.copy(includeScala = false) },
  packagedArtifact in Compile in packageBin := {
    val temp = (packagedArtifact in Compile in packageBin).value
    println(temp)
    val (art, slimJar) = temp
    val fatJar = new File(crossTarget.value + "/" + (jarName in assembly).value)
    val _ = assembly.value
    IO.copy(List(fatJar -> slimJar), overwrite = true)
    println("Using sbt-assembly to package library dependencies into a fat jar for publication")
    (art, slimJar)
  }
).dependsOn(simpleGraph, compilerPluginUnitTestLib)

lazy val canveSbtPlugin = (project in file("sbt-plugin")).settings(
  organization := "canve",
  name := "sbt-plugin",
  isSnapshot := true, // to enable overwriting the existing artifact version
  scalaVersion := "2.10.4",
  crossScalaVersions := Seq("2.10.4"),
  sbtPlugin := true
  //resolvers += "Sonatype OSS Snapshots" at "https://oss.sonatype.org/content/repositories/snapshots",
  //libraryDependencies ++= Seq("com.github.tototoshi" %% "scala-csv" % "1.3.0-SNAPSHOT") 
).dependsOn(compilerPluginn)

lazy val sbtPluginTestLib = (project in file("sbt-plugin-test-lib")).settings(
  name := "sbt-plugin-test-lib",
  organization := "canve",
  version := "0.0.1",

  /*
   * this project is purely running sbt as an OS process, so it can use latest scala version not sbt's scala version,
   * and there is no need whatsoever to provided a cross-compilation of it for older scala.
   */
  scalaVersion := "2.11.7", 
  crossScalaVersions := Seq("2.11.7"),
  
  /*
   * The following resolver is added as a workaround: the `update task` of this subproject,
   * may oddly enough try to resolve scala-csv, which in turn may fail if the resolver for it is not in scope here.
   */
  resolvers += "Sonatype OSS Snapshots" at "https://oss.sonatype.org/content/repositories/snapshots",

  libraryDependencies ++= Seq(
    "org.scala-lang" % "scala-compiler" % scalaVersion.value % "provided", // otherwise cannot use scala.tools.nsc.io.File
    "org.fusesource.jansi" % "jansi" % "1.4"
  ),
  
  publishArtifact := false,

  (run in Compile) <<= (run in Compile).dependsOn(publishLocal in canveSbtPlugin)

).dependsOn(compilerPluginn)