5 files changed, 44 insertions, 4 deletions

diff --git a/src/actors/scala/actors/Actor.scala b/src/actors/scala/actors/Actor.scala
index fb90cb9c46..907389b9f0 100644
--- a/src/actors/scala/actors/Actor.scala
+++ b/src/actors/scala/actors/Actor.scala
@@ -646,6 +646,7 @@ trait Actor extends AbstractActor with ReplyReactor with ReplyableActor {
   }
 
   // guarded by lock of this
+  // never throws SuspendActorException
   private[actors] override def scheduleActor(f: Any =>? Unit, msg: Any) =
     if ((f eq null) && (continuation eq null)) {
       // do nothing (timeout is handled instead)
@@ -825,6 +826,13 @@ trait Actor extends AbstractActor with ReplyReactor with ReplyableActor {
           resumeActor()
         else if (waitingFor ne waitingForNone) {
           scheduleActor(continuation, null)
+          /* Here we should not throw a SuspendActorException,
+             since the current method is called from an actor that
+             is in the process of exiting.
+
+             Therefore, the contract for scheduleActor is that
+             it never throws a SuspendActorException.
+           */
         }
       }
   }
diff --git a/src/actors/scala/actors/Debug.scala b/src/actors/scala/actors/Debug.scala
index 481b68d7f4..bad19b8aeb 100644
--- a/src/actors/scala/actors/Debug.scala
+++ b/src/actors/scala/actors/Debug.scala
@@ -27,6 +27,15 @@ object Debug {
 
   def error(s: String) =
     if (lev > 0) System.err.println("Error: " + s)
+
+  def doInfo(b: => Unit) =
+    if (lev > 2) b
+
+  def doWarning(b: => Unit) =
+    if (lev > 1) b
+
+  def doError(b: => Unit) =
+    if (lev > 0) b
 }
 
 class Debug(tag: String) {
diff --git a/src/actors/scala/actors/Reactor.scala b/src/actors/scala/actors/Reactor.scala
index d641f54eb6..8545b92d1e 100644
--- a/src/actors/scala/actors/Reactor.scala
+++ b/src/actors/scala/actors/Reactor.scala
@@ -108,8 +108,17 @@ trait Reactor extends OutputChannel[Any] {
     // assert continuation != null
     if (onSameThread)
       continuation(item._1)
-    else
+    else {
       scheduleActor(continuation, item._1)
+      /* Here, we throw a SuspendActorException to avoid
+         terminating this actor when the current ReactorTask
+         is finished.
+
+         The SuspendActorException skips the termination code
+         in ReactorTask.
+       */
+      throw Actor.suspendException
+    }
   }
 
   def !(msg: Any) {
@@ -149,7 +158,14 @@ trait Reactor extends OutputChannel[Any] {
             // keep going
           } else {
             waitingFor = handlesMessage
-            done = true
+            /* Here, we throw a SuspendActorException to avoid
+               terminating this actor when the current ReactorTask
+               is finished.
+
+               The SuspendActorException skips the termination code
+               in ReactorTask.
+             */
+            throw Actor.suspendException
           }
         }
       } else {
@@ -171,6 +187,8 @@ trait Reactor extends OutputChannel[Any] {
    * an actors act method.
    *
    * assume handler != null
+   *
+   * never throws SuspendActorException
    */
   private[actors] def scheduleActor(handler: Any =>? Unit, msg: Any) = {
     val fun = () => handler(msg)
diff --git a/src/actors/scala/actors/ReactorTask.scala b/src/actors/scala/actors/ReactorTask.scala
index 28e93bbbff..f6ec67e94c 100644
--- a/src/actors/scala/actors/ReactorTask.scala
+++ b/src/actors/scala/actors/ReactorTask.scala
@@ -46,6 +46,7 @@ private[actors] class ReactorTask[T >: Null <: Reactor](var reactor: T, var fun:
 
       case e: Exception =>
         Debug.info(reactor+": caught "+e)
+        Debug.doInfo { e.printStackTrace() }
         reactor.terminated()
         afterExecuting(e)
     } finally {
diff --git a/src/actors/scala/actors/ReplyReactor.scala b/src/actors/scala/actors/ReplyReactor.scala
index 4b31369db4..64860f4d38 100644
--- a/src/actors/scala/actors/ReplyReactor.scala
+++ b/src/actors/scala/actors/ReplyReactor.scala
@@ -57,8 +57,11 @@ trait ReplyReactor extends Reactor with ReplyableReactor {
     // assert continuation != null
     if (onSameThread)
       continuation(item._1)
-    else
+    else {
       scheduleActor(continuation, item._1)
+      // see Reactor.resumeReceiver
+      throw Actor.suspendException
+    }
   }
 
   // assume continuation != null
@@ -83,7 +86,8 @@ trait ReplyReactor extends Reactor with ReplyableReactor {
             // keep going
           } else {
             waitingFor = handlesMessage
-            done = true
+            // see Reactor.searchMailbox
+            throw Actor.suspendException
           }
         }
       } else {