Add a pending test for sbt/sbt#1142

Add a scripted test documents the current behavior of incremental
compiler when it comes to handling of inherited macros. A whitespace
change to a file that inherits a macro triggers recompilation of all files that
depend (by composition or inheritance) on that file.

sbt/src/sbt-test/source-dependencies/inherited-macros/changes/Client.scala

@@ -0,0 +1,7 @@
+package macro
+
+object Client {
+	object RealClient extends Provider {
+		// Some comment...
+	}
+}

sbt/src/sbt-test/source-dependencies/inherited-macros/macro-client/build.sbt

@@ -0,0 +1,9 @@
+// Check that a file has not been recompiled during last compilation
+InputKey[Unit]("check-not-recompiled") <<= inputTask { (argTask: TaskKey[Seq[String]]) =>
+    (argTask, compile in Compile) map { (args: Seq[String], a: sbt.inc.Analysis) =>
+        assert(args.size == 1)
+        val fileCompilation = a.apis.internal.collect { case (file, src) if file.name.endsWith(args(0)) => src.compilation }.head
+        val lastCompilation = a.compilations.allCompilations.last
+        assert(fileCompilation.startTime != lastCompilation.startTime, "File has been recompiled during last compilation.")
+    }
+}

sbt/src/sbt-test/source-dependencies/inherited-macros/macro-client/src/main/scala/Client.scala

@@ -0,0 +1,7 @@
+package macro
+
+object Client {
+	object RealClient extends Provider {
+
+	}
+}

sbt/src/sbt-test/source-dependencies/inherited-macros/macro-client/src/main/scala/Foo.scala

@@ -0,0 +1,5 @@
+package macro
+
+object Foo {
+	val c = Client.RealClient
+}

sbt/src/sbt-test/source-dependencies/inherited-macros/macro-provider/src/main/scala/Provider.scala

@@ -0,0 +1,7 @@
+package macro
+import scala.language.experimental.macros
+import scala.reflect.macros._
+
+abstract class Provider {
+	def notImplementedMacro = macro ???
+}

sbt/src/sbt-test/source-dependencies/inherited-macros/pending

@@ -0,0 +1,12 @@
+> macro-provider/compile
+
+> macro-client/compile
+
+# Introduce a comment in Client, which inherits a macro from Provider
+$ copy-file changes/Client.scala macro-client/src/main/scala/Client.scala
+
+> macro-client/compile
+
+# Object Foo depends on Client via composition, thus a whitespace change to
+# Client shouldn't trigger its recompilation
+> check-not-recompiled Foo.scala

sbt/src/sbt-test/source-dependencies/inherited-macros/project/build.scala

@@ -0,0 +1,29 @@
+import sbt._
+import Keys._
+
+object build extends Build {
+	val defaultSettings = Seq(
+		libraryDependencies <+= scalaVersion("org.scala-lang" % "scala-reflect" % _ )//,
+		//incOptions := incOptions.value.withNameHashing(true)
+	)
+
+	lazy val root = Project(
+	   base = file("."),
+	   id = "macro",
+	   aggregate = Seq(macroProvider, macroClient),
+	   settings = Defaults.defaultSettings ++ defaultSettings
+	)
+
+	lazy val macroProvider = Project(
+	   base = file("macro-provider"),
+	   id = "macro-provider",
+	   settings = Defaults.defaultSettings ++ defaultSettings
+	)
+
+	lazy val macroClient = Project(
+	   base = file("macro-client"),
+	   id = "macro-client",
+	   dependencies = Seq(macroProvider),
+	   settings = Defaults.defaultSettings ++ defaultSettings
+	)
+}