Fix for a race condition when starting an Actor...

Fix for a race condition when starting an Actor while its
ForkJoinScheduler is shutting down.

3 files changed, 21 insertions, 6 deletions

diff --git a/src/actors/scala/actors/Actor.scala b/src/actors/scala/actors/Actor.scala
index 366141f33b..2adf3f5ffd 100644
--- a/src/actors/scala/actors/Actor.scala
+++ b/src/actors/scala/actors/Actor.scala
@@ -686,10 +686,8 @@ trait Actor extends AbstractActor with ReplyReactor with ReplyableActor {
     exiting = false
     shouldExit = false
 
-    scheduler execute {
-      scheduler.newActor(Actor.this)
-      (new Reaction(Actor.this)).run()
-    }
+    scheduler.newActor(this)
+    scheduler.execute(new Reaction(this))
 
     this
   }
diff --git a/src/actors/scala/actors/scheduler/DelegatingScheduler.scala b/src/actors/scala/actors/scheduler/DelegatingScheduler.scala
index b25e3d26f5..434911c48d 100644
--- a/src/actors/scala/actors/scheduler/DelegatingScheduler.scala
+++ b/src/actors/scala/actors/scheduler/DelegatingScheduler.scala
@@ -48,7 +48,22 @@ private[actors] trait DelegatingScheduler extends IScheduler {
     }
   }
 
-  def newActor(actor: Reactor) = impl.newActor(actor)
+  def newActor(actor: Reactor) = synchronized {
+    val createNew = if (sched eq null)
+      true
+    else sched.synchronized {
+      if (!sched.isActive)
+        true
+      else {
+        sched.newActor(actor)
+        false
+      }
+    }
+    if (createNew) {
+      sched = makeNewScheduler()
+      sched.newActor(actor)
+    }
+  }
 
   def terminated(actor: Reactor) = impl.terminated(actor)
 
diff --git a/src/actors/scala/actors/scheduler/ForkJoinScheduler.scala b/src/actors/scala/actors/scheduler/ForkJoinScheduler.scala
index 86fb14db50..b0198d4879 100644
--- a/src/actors/scala/actors/scheduler/ForkJoinScheduler.scala
+++ b/src/actors/scala/actors/scheduler/ForkJoinScheduler.scala
@@ -69,6 +69,7 @@ class ForkJoinScheduler(val initCoreSize: Int, val maxSize: Int, daemon: Boolean
 
           if (allTerminated) {
             Debug.info(this+": all actors terminated")
+            terminating = true
             throw new QuitException
           }
 
@@ -79,6 +80,7 @@ class ForkJoinScheduler(val initCoreSize: Int, val maxSize: Int, daemon: Boolean
             val num = pool.drainTasksTo(list)
             Debug.info(this+": drained "+num+" tasks")
             drainedTasks = list
+            terminating = true
             throw new QuitException
           }
         }
@@ -127,7 +129,7 @@ class ForkJoinScheduler(val initCoreSize: Int, val maxSize: Int, daemon: Boolean
   }
 
   def isActive = synchronized {
-    (pool ne null) && !pool.isShutdown()
+    !terminating && (pool ne null) && !pool.isShutdown()
   }
 
   override def managedBlock(blocker: scala.concurrent.ManagedBlocker) {