Package interactive and scaladoc into compiler jar.

Ant build puts class files for interactive and scaladoc into compiler jar.
We mirror that behavior by disabling docs and publishing tasks in
interactive and scaladoc subprojects. We include class files generated by
those two projects in compiler by merging `mappings` tasks. Mappings is
what package tasks uses to determine which class files should end up in
a jar file.

Author: gkossakowski

build.sbt

@@ -84,6 +84,17 @@ lazy val commonSettings = Seq[Setting[_]](
   cleanFiles += (classDirectory in Compile).value
 )
 
+// disable various tasks that are not needed for projects that are used
+// only for compiling code and not publishing it as a standalone artifact
+// we disable those tasks by overriding them and returning bogus files when
+// needed. This is a bit sketchy but I haven't found any better way.
+val disableDocsAndPublishingTasks = Seq[Setting[_]](
+  (doc := file("!!! NO DOCS !!!")),
+  (publishLocal := {}),
+  (publish := {}),
+  (packageBin in Compile := file("!!! NO PACKAGING !!!"))
+)
+
 lazy val scalaSubprojectSettings = commonSettings ++ Seq[Setting[_]](
   artifactPath in packageBin in Compile := {
     // two lines below are copied over from sbt's sources:
@@ -121,16 +132,26 @@ lazy val reflect = configureAsSubproject(project).
   dependsOn(library)
 
 lazy val compiler = configureAsSubproject(project).
-  settings(libraryDependencies += "org.apache.ant" % "ant" % "1.9.4").
+  settings(libraryDependencies += "org.apache.ant" % "ant" % "1.9.4",
+    // this a way to make sure that classes from interactive and scaladoc projects
+    // end up in compiler jar (that's what Ant build does)
+    // we need to use LocalProject references (with strings) to deal with mutual recursion
+    mappings in Compile in packageBin :=
+      (mappings in Compile in packageBin).value ++
+      (mappings in Compile in packageBin in LocalProject("interactive")).value ++
+      (mappings in Compile in packageBin in LocalProject("scaladoc")).value
+    ).
   dependsOn(library, reflect, asm)
 
 lazy val interactive = configureAsSubproject(project).
+  settings(disableDocsAndPublishingTasks: _*).
   dependsOn(compiler)
 
 lazy val repl = configureAsSubproject(project).
   // TODO: in Ant build def, this version is defined in versions.properties
   // figure out whether we also want to externalize jline's version
   settings(libraryDependencies += "jline" % "jline" % "2.12").
+  settings(disableDocsAndPublishingTasks: _*).
   dependsOn(compiler)
 
 lazy val scaladoc = configureAsSubproject(project).
@@ -141,6 +162,7 @@ lazy val scaladoc = configureAsSubproject(project).
       "org.scala-lang.modules" %% "scala-partest" % "1.0.5"
     )
   ).
+  settings(disableDocsAndPublishingTasks: _*).
   dependsOn(compiler)
 
 lazy val scalap = configureAsSubproject(project).
@@ -192,18 +214,9 @@ def configureAsSubproject(project: Project): Project = {
  */
 def configureAsForkOfJavaProject(project: Project): Project = {
   val base = file(".") / "src" / project.id
-  // disable various tasks that do not make sense for forks of Java projects
-  // we disable those task by overriding them and returning bogus files when
-  // needed. This is a bit sketchy but I haven't found any better way.
-  val disableTasks = Seq[Setting[_]](
-    (doc := file("!!! NO DOCS !!!")),
-    (publishLocal := {}),
-    (publish := {}),
-    (packageBin in Compile := file("!!! NO PACKAGING !!!"))
-  )
   (project in base).
     settings(commonSettings: _*).
-    settings(disableTasks: _*).
+    settings(disableDocsAndPublishingTasks: _*).
     settings(
       sourceDirectory in Compile := baseDirectory.value,
       javaSource in Compile := (sourceDirectory in Compile).value,