Fixed thread-visibility issues causing scala-ni...

Fixed thread-visibility issues causing scala-nightly-args 387 to fail.

3 files changed, 9 insertions, 0 deletions

diff --git a/src/actors/scala/actors/Actor.scala b/src/actors/scala/actors/Actor.scala
index 26b4661170..057436a514 100644
--- a/src/actors/scala/actors/Actor.scala
+++ b/src/actors/scala/actors/Actor.scala
@@ -390,6 +390,7 @@ trait Actor extends AbstractActor with ReplyReactor with ReplyableActor {
    * the invocation of send to the place where the thread of
    * the receiving actor resumes inside receive/receiveWithin.
    */
+  @volatile
   private var received: Option[Any] = None
 
   /* This option holds a TimerTask when the actor waits in a
diff --git a/src/actors/scala/actors/Reactor.scala b/src/actors/scala/actors/Reactor.scala
index 63c9ff32bd..a3e44d4d2c 100644
--- a/src/actors/scala/actors/Reactor.scala
+++ b/src/actors/scala/actors/Reactor.scala
@@ -27,6 +27,7 @@ trait Reactor extends OutputChannel[Any] {
   /* If the actor waits in a react, continuation holds the
    * message handler that react was called with.
    */
+  @volatile
   private[actors] var continuation: PartialFunction[Any, Unit] = null
 
   /* Whenever this Actor executes on some thread, waitingFor is
@@ -37,6 +38,8 @@ trait Reactor extends OutputChannel[Any] {
    * thread.
    */
   private[actors] val waitingForNone = (m: Any) => false
+
+  // guarded by lock of this
   private[actors] var waitingFor: Any => Boolean = waitingForNone
 
   /**
@@ -82,6 +85,9 @@ trait Reactor extends OutputChannel[Any] {
   private[actors] def makeReaction(fun: () => Unit): Runnable =
     new ReactorTask(this, fun)
 
+  /* Note that this method is called without holding a lock.
+   * Therefore, to read an up-to-date continuation, it must be @volatile.
+   */
   private[actors] def resumeReceiver(item: (Any, OutputChannel[Any]), onSameThread: Boolean) {
     // assert continuation != null
     if (onSameThread)
@@ -166,6 +172,7 @@ trait Reactor extends OutputChannel[Any] {
    * built on top of `seq`. Note that the only invocation of
    * `kill` is supposed to be inside `Reaction.run`.
    */
+  @volatile
   private[actors] var kill: () => Unit =
     () => { exit() }
 
diff --git a/src/actors/scala/actors/ReplyReactor.scala b/src/actors/scala/actors/ReplyReactor.scala
index 9e59c4956d..db7a74aba5 100644
--- a/src/actors/scala/actors/ReplyReactor.scala
+++ b/src/actors/scala/actors/ReplyReactor.scala
@@ -24,6 +24,7 @@ trait ReplyReactor extends Reactor {
   /* A list of the current senders. The head of the list is
    * the sender of the message that was received last.
    */
+  @volatile
   private[actors] var senders: List[OutputChannel[Any]] =
     Nil