Change TaskRunner to throw an exception instead of using Either

cache/Cache.scala

@@ -9,7 +9,7 @@ trait Cache[I,O]
 }
 trait SBinaryFormats extends CollectionTypes with JavaFormats with NotNull
 {
-	//TODO: add basic types minus FileFormat
+	//TODO: add basic types from SBinary minus FileFormat
 }
 object Cache extends BasicCacheImplicits with SBinaryFormats with HListCacheImplicits
 {

tasks/TaskRunner.scala

@@ -2,16 +2,17 @@ package xsbt
 
 object TaskRunner
 {
-	def apply[T](node: Task[T]): Either[ List[WorkFailure[Task[_]]] , T ] = apply(node, Runtime.getRuntime.availableProcessors)
+	def apply[T](node: Task[T]): T = apply(node, Runtime.getRuntime.availableProcessors)
 	/** Executes work for nodes in a directed acyclic graph with root node `node`.
 	* The maximum number of tasks to execute simultaneously is `maximumTasks`. */
-	def apply[T](node: Task[T], maximumTasks: Int): Either[ List[WorkFailure[Task[_]]] , T ] =
+	def apply[T](node: Task[T], maximumTasks: Int): T =
 	{
 		require(maximumTasks > 0)
 		val compute = new Compute[Work.Job, Result] { def apply[A](w: Work.Job[A]) = w.apply }
 		val strategy = new SimpleStrategy[Work[_,_]]
 		val scheduler = new TaskScheduler(node, strategy, new BasicTaskListener)
 		val distributor = new Distributor[ Either[ List[WorkFailure[Task[_]]], T ] , Work.Job, Result](scheduler, compute, maximumTasks)
-		distributor.run()
+		distributor.run().fold(failures => throw new TasksFailed(failures), identity[T])
 	}
-}
+}
+final case class TasksFailed(failures: List[WorkFailure[Task[_]]]) extends RuntimeException(failures.length + " failed")

tasks/src/test/scala/TaskRunnerCircular.scala

@@ -41,7 +41,8 @@ object TaskRunnerCircularTest extends Properties("TaskRunner Circular")
 				} named("it_" + i)
 			it
 		}
-		TaskRunner(top, workers).fold(_.exists(_.exception.isInstanceOf[CircularDependency]), x => false)
+		try { TaskRunner(top, workers); false }
+		catch { case TasksFailed(failures) => failures.exists(_.exception.isInstanceOf[CircularDependency]) }
 	}
 	final def checkRootComplete(intermediate: Int, workers: Int) =
 	{

tasks/src/test/scala/TestRunnerCall.scala

@@ -11,7 +11,7 @@ object TaskRunnerCallTest extends Properties("TaskRunner Call")
 			("Workers: " + workers) |: ("i: " + i) |: ("fib(i): " + f) |:
 			{
 				def result = TaskRunner( fibTask(i), workers)
-				("Result: " + result) |: (result == Right(f))
+				checkResult(result, f)
 			}
 		}
 	)

tasks/src/test/scala/TestRunnerSort.scala

@@ -12,7 +12,7 @@ object TaskRunnerSortTest extends Properties("TaskRunnerSort")
 			("Workers: " + workers) |: ("Array: " + a.toList) |:
 			{
 				def result = TaskRunner( sort(a.toArray), workers)
-				checkResult(result.right.map(_.toList), sorted.toList)
+				checkResult(result.toList, sorted.toList)
 			}
 		}
 	)

tasks/src/test/scala/checkResult.scala

@@ -4,23 +4,19 @@ import org.scalacheck.Prop._
 
 object checkResult
 {
-	def apply[T](run: => Either[List[WorkFailure[Task[_]]],T], expected: T) =
+	def apply[T](run: => T, expected: T) =
 	{
 		("Expected: " + expected) |:
 		(try
 		{
 			val actual = run
-			("Actual: " + actual) |:
+			("Actual: " + actual) |: (actual == expected)
-			(actual match
-			{
-				case Right(a) => a == expected
-				case Left(failures) =>
-					failures.foreach(f => f.exception.printStackTrace)
-					false
-			})
 		}
 		catch
 		{
+			case TasksFailed(failures) =>
+				failures.foreach(f => f.exception.printStackTrace)
+				"One or more tasks failed" |: false
 			case e =>
 				e.printStackTrace
 				"Error in framework" |: false