Improved handling of uncaught exceptions in act...

Improved handling of uncaught exceptions in actors. See #711. Review by
community.

4 files changed, 25 insertions, 11 deletions

diff --git a/src/actors/scala/actors/ActorTask.scala b/src/actors/scala/actors/ActorTask.scala
index 2fa24f93af..6757a69a43 100644
--- a/src/actors/scala/actors/ActorTask.scala
+++ b/src/actors/scala/actors/ActorTask.scala
@@ -29,7 +29,7 @@ private[actors] class ActorTask(actor: Actor,
       actor.exit()
   }
 
-  protected override def terminateExecution(e: Exception) {
+  protected override def terminateExecution(e: Throwable) {
     val senderInfo = try { Some(actor.sender) } catch {
       case _: Exception => None
     }
diff --git a/src/actors/scala/actors/IScheduler.scala b/src/actors/scala/actors/IScheduler.scala
index 1718dab045..f65aa020f8 100644
--- a/src/actors/scala/actors/IScheduler.scala
+++ b/src/actors/scala/actors/IScheduler.scala
@@ -68,6 +68,25 @@ trait IScheduler {
 
   def managedBlock(blocker: scala.concurrent.ManagedBlocker): Unit
 
+  /** This method is called when an exception is not handled by
+   *  some reactor while processing a certain message.
+   *
+   *  @param t       the unhandled exception
+   *  @param reactor the reactor inside which the exception was thrown
+   *  @param msg     the message last removed from the reactor's mailbox
+   */
+  def handleUncaughtThrowable[Msg >: Null](t: Throwable, reactor: Reactor[Msg], msg: Msg) {
+    // print message on default error stream
+    val msgException = "Uncaught exception in "+reactor+"\n"
+    val msgMessage   = if (msg != null) "Message: "+msg+"\n" else ""
+    Debug.doWarning {
+      Console.err.print(msgException + msgMessage)
+      t.printStackTrace()
+    }
+    if (t.isInstanceOf[Error])
+      throw t
+  }
+
   @deprecated("this member is going to be removed in a future release")
   def tick(a: Actor) {}
 
diff --git a/src/actors/scala/actors/ReactorTask.scala b/src/actors/scala/actors/ReactorTask.scala
index 3f9ebb6fa7..2e25459c9d 100644
--- a/src/actors/scala/actors/ReactorTask.scala
+++ b/src/actors/scala/actors/ReactorTask.scala
@@ -49,14 +49,9 @@ private[actors] class ReactorTask[Msg >: Null](var reactor: Reactor[Msg],
       case _: SuspendActorControl =>
         // do nothing (continuation is already saved)
 
-      case e: Exception =>
-        // print message on default error stream
-        val msgException = "Uncaught exception in "+reactor+"\n"
-        val msgMessage   = if (msg != null) "Message: "+msg+"\n" else ""
-        Debug.doWarning {
-          Console.err.print(msgException + msgMessage)
-          e.printStackTrace()
-        }
+      case e: Throwable =>
+        // re-throws `Error`s by default
+        reactor.scheduler.handleUncaughtThrowable(e, reactor, msg)
 
         terminateExecution(e)
         reactor.terminated()
@@ -77,6 +72,6 @@ private[actors] class ReactorTask[Msg >: Null](var reactor: Reactor[Msg],
 
   protected def suspendExecution() {}
 
-  protected def terminateExecution(e: Exception) {}
+  protected def terminateExecution(e: Throwable) {}
 
 }
diff --git a/src/actors/scala/actors/UncaughtException.scala b/src/actors/scala/actors/UncaughtException.scala
index 54c28f66cf..1829d48606 100644
--- a/src/actors/scala/actors/UncaughtException.scala
+++ b/src/actors/scala/actors/UncaughtException.scala
@@ -23,7 +23,7 @@ class UncaughtException[Msg >: Null](val actor: Reactor[Msg],
                                      val message: Option[Msg],
                                      val sender: Option[OutputChannel[Any]],
                                      val thread: Thread,
-                                     cause: Exception)
+                                     cause: Throwable)
 extends Exception(cause) {
 
   override def toString() =