Test for inheritance and member references.

Add a test-case that documents current behavior of incremental
compiler when it comes to invalidating dependencies that arise
from inheritance and member references.

sbt/src/sbt-test/source-dependencies/transitive-memberRef/build.sbt

@@ -0,0 +1,36 @@
+logLevel := Level.Debug
+
+// disable sbt's heauristic which recompiles everything in case
+// some fraction (e.g. 50%) of files is scheduled to be recompiled
+// in this test we want precise information about recompiled files
+// which that heuristic would distort
+incOptions := incOptions.value.copy(recompileAllFraction = 1.0)
+
+/* Performs checks related to compilations:
+ *  a) checks in which compilation given set of files was recompiled
+ *  b) checks overall number of compilations performed
+ */
+TaskKey[Unit]("check-compilations") <<= (compile in Compile, scalaSource in Compile) map { (a: sbt.inc.Analysis, src: java.io.File) =>
+  def relative(f: java.io.File): java.io.File =  f.relativeTo(src) getOrElse f
+  val allCompilations = a.compilations.allCompilations
+  val recompiledFiles: Seq[Set[java.io.File]] = allCompilations map { c =>
+    val recompiledFiles = a.apis.internal.collect {
+      case (file, api) if api.compilation.startTime == c.startTime => relative(file)
+    }
+    recompiledFiles.toSet
+  }
+  def recompiledFilesInIteration(iteration: Int, fileNames: Set[String]) = {
+    val files = fileNames.map(new java.io.File(_))
+    assert(recompiledFiles(iteration) == files, "%s != %s".format(recompiledFiles(iteration), files))
+  }
+  // Y.scala is compiled only at the beginning as changes to A.scala do not affect it
+  recompiledFilesInIteration(0, Set("Y.scala"))
+  // A.scala is changed and recompiled
+  recompiledFilesInIteration(1, Set("A.scala"))
+  // change in A.scala causes recompilation of B.scala, C.scala, D.scala which depend on transtiviely
+  // and by inheritance on A.scala
+  // X.scala is also recompiled because it depends by member reference on B.scala
+  // Note that Y.scala is not recompiled because it depends just on X through member reference dependency
+  recompiledFilesInIteration(2, Set("B.scala", "C.scala", "D.scala", "X.scala"))
+  assert(allCompilations.size == 3)
+}

sbt/src/sbt-test/source-dependencies/transitive-memberRef/changes/A1.scala

@@ -0,0 +1,5 @@
+package test
+
+class A {
+	def foo: Int = 23
+}

sbt/src/sbt-test/source-dependencies/transitive-memberRef/src/main/scala/A.scala

@@ -0,0 +1,3 @@
+package test
+
+class A

sbt/src/sbt-test/source-dependencies/transitive-memberRef/src/main/scala/B.scala

@@ -0,0 +1,3 @@
+package test
+
+class B extends A

sbt/src/sbt-test/source-dependencies/transitive-memberRef/src/main/scala/C.scala

@@ -0,0 +1,3 @@
+package test
+
+class C extends B

sbt/src/sbt-test/source-dependencies/transitive-memberRef/src/main/scala/D.scala

@@ -0,0 +1,3 @@
+package test
+
+class D extends C

sbt/src/sbt-test/source-dependencies/transitive-memberRef/src/main/scala/X.scala

@@ -0,0 +1,5 @@
+package test
+
+class X {
+	def bar(b: B) = b
+}

sbt/src/sbt-test/source-dependencies/transitive-memberRef/src/main/scala/Y.scala

@@ -0,0 +1,5 @@
+package test
+
+class Y {
+	def baz(x: X) = x
+}

sbt/src/sbt-test/source-dependencies/transitive-memberRef/test

@@ -0,0 +1,11 @@
+# introduces first compile iteration
+> compile
+# adds a new method to A which will cause transitive invalidation
+# of all source files that inherit from it
+# also, all direct dependencies of files that inherit from A will
+# be invalidated (in our case that's X.scala)
+$ copy-file changes/A1.scala src/main/scala/A.scala
+# second iteration
+> compile
+# check in which compile iteration given source file got recompiled
+> check-compilations