Move hotswap stack into Actor trait. See #1717

akka-actor/src/main/scala/Errtest.scala

@@ -0,0 +1,49 @@
+
+import akka.actor._
+import com.typesafe.config.ConfigFactory
+import akka.event.LoggingReceive
+import scala.annotation.tailrec
+
+object Errtest extends App {
+
+  val config = ConfigFactory.parseString("""
+    akka.loglevel = DEBUG
+    akka.actor.debug {
+      receive = on
+      lifecycle = on
+    }
+    """)
+
+  val sys = ActorSystem("ErrSys", config)
+  val top = sys.actorOf(Props[Top], name = "top")
+
+  for (n ← 1 to 100) {
+    top ! "run " + n
+    Thread.sleep(1000)
+  }
+}
+
+class Top extends Actor {
+  var c: ActorRef = _
+  def receive = LoggingReceive {
+    case x ⇒
+      c = context.actorOf(Props[Child]);
+      c ! "ok"
+  }
+}
+
+class Child extends Actor {
+
+  //throw new Error("Simulated ERR")
+  blowUp(0)
+
+  //not @tailrec
+  private final def blowUp(n: Long): Long = {
+    blowUp(n + 1) + 1
+  }
+
+  def receive = LoggingReceive {
+    case x ⇒
+    //context.system.shutdown();
+  }
+}

akka-actor/src/main/scala/akka/actor/Actor.scala

@@ -7,6 +7,7 @@ package akka.actor
 import akka.AkkaException
 import scala.reflect.BeanProperty
 import scala.util.control.NoStackTrace
+import scala.collection.immutable.Stack
 import java.util.regex.Pattern
 
 /**
@@ -112,6 +113,8 @@ object Actor {
     def isDefinedAt(x: Any) = false
     def apply(x: Any) = throw new UnsupportedOperationException("Empty behavior apply()")
   }
+
+  private final val emptyBehaviourStack: Stack[Actor.Receive] = Stack.empty
 }
 
 /**
@@ -172,7 +175,7 @@ trait Actor {
   type Receive = Actor.Receive
 
   /**
-   * Stores the context for this actor, including self, sender, and hotswap.
+   * Stores the context for this actor, including self, and sender.
    * It is implicit to support operations such as `forward`.
    *
    * [[akka.actor.ActorContext]] is the Scala API. `getContext` returns a
@@ -282,7 +285,6 @@ trait Actor {
   // =========================================
 
   private[akka] final def apply(msg: Any) = {
-    val behaviorStack = context.asInstanceOf[ActorCell].hotswap
     msg match {
       case msg if behaviorStack.nonEmpty && behaviorStack.head.isDefinedAt(msg) ⇒ behaviorStack.head.apply(msg)
       case msg if behaviorStack.isEmpty && processingBehavior.isDefinedAt(msg) ⇒ processingBehavior.apply(msg)
@@ -291,5 +293,18 @@ trait Actor {
   }
 
   private[this] val processingBehavior = receive //ProcessingBehavior is the original behavior
+
+  private[akka] def pushBehavior(behavior: Receive): Unit = {
+    behaviorStack = behaviorStack.push(behavior)
+  }
+
+  private[akka] def popBehavior(): Unit = {
+    val stack = behaviorStack
+    if (stack.nonEmpty) behaviorStack = stack.pop
+  }
+
+  private[akka] def clearBehaviorStack(): Unit = { behaviorStack = emptyBehaviourStack }
+
+  private var behaviorStack: Stack[PartialFunction[Any, Unit]] = emptyBehaviourStack
 }
 

akka-actor/src/main/scala/akka/actor/ActorCell.scala

@@ -174,8 +174,7 @@ private[akka] class ActorCell(
   val self: InternalActorRef,
   val props: Props,
   @volatile var parent: InternalActorRef,
-  /*no member*/ _receiveTimeout: Option[Duration],
-  var hotswap: Stack[PartialFunction[Any, Unit]]) extends UntypedActorContext {
+  /*no member*/ _receiveTimeout: Option[Duration]) extends UntypedActorContext {
 
   import ActorCell._
 
@@ -389,7 +388,6 @@ private[akka] class ActorCell(
         }
       }
       actor = freshActor // assign it here so if preStart fails, we can null out the sef-refs next call
-      hotswap = Props.noHotSwap // Reset the behavior
       freshActor.postRestart(cause)
       if (system.settings.DebugLifecycle) system.eventStream.publish(Debug(self.path.toString, clazz(freshActor), "restarted"))
 
@@ -509,9 +507,9 @@ private[akka] class ActorCell(
     }
   }
 
-  def become(behavior: Actor.Receive, discardOld: Boolean = true) {
+  def become(behavior: Actor.Receive, discardOld: Boolean = true): Unit = {
     if (discardOld) unbecome()
-    hotswap = hotswap.push(behavior)
+    actor.pushBehavior(behavior)
   }
 
   /**
@@ -527,10 +525,7 @@ private[akka] class ActorCell(
     become(newReceive, discardOld)
   }
 
-  def unbecome() {
-    val h = hotswap
-    if (h.nonEmpty) hotswap = h.pop
-  }
+  def unbecome(): Unit = actor.popBehavior()
 
   def autoReceiveMessage(msg: Envelope) {
     if (system.settings.DebugAutoReceive)
@@ -547,9 +542,9 @@ private[akka] class ActorCell(
   }
 
   private def doTerminate() {
-    try {
-      try {
     val a = actor
+    try {
+      try {
         if (a ne null) a.postStop()
       } finally {
         dispatcher.detach(this)
@@ -563,7 +558,7 @@ private[akka] class ActorCell(
       } finally {
         currentMessage = null
         clearActorFields()
-        hotswap = Props.noHotSwap
+        if (a ne null) a.clearBehaviorStack()
       }
     }
   }

akka-actor/src/main/scala/akka/actor/ActorRef.scala

@@ -224,8 +224,7 @@ private[akka] class LocalActorRef private[akka] (
   _supervisor: InternalActorRef,
   val path: ActorPath,
   val systemService: Boolean = false,
-  _receiveTimeout: Option[Duration] = None,
-  _hotswap: Stack[PartialFunction[Any, Unit]] = Props.noHotSwap)
+  _receiveTimeout: Option[Duration] = None)
   extends InternalActorRef with LocalRef {
 
   /*
@@ -238,7 +237,7 @@ private[akka] class LocalActorRef private[akka] (
    * us to use purely factory methods for creating LocalActorRefs.
    */
   @volatile
-  private var actorCell = newActorCell(_system, this, _props, _supervisor, _receiveTimeout, _hotswap)
+  private var actorCell = newActorCell(_system, this, _props, _supervisor, _receiveTimeout)
   actorCell.start()
 
   protected def newActorCell(
@@ -246,9 +245,8 @@ private[akka] class LocalActorRef private[akka] (
     ref: InternalActorRef,
     props: Props,
     supervisor: InternalActorRef,
-    receiveTimeout: Option[Duration],
-    hotswap: Stack[PartialFunction[Any, Unit]]): ActorCell =
-    new ActorCell(system, ref, props, supervisor, receiveTimeout, hotswap)
+    receiveTimeout: Option[Duration]): ActorCell =
+    new ActorCell(system, ref, props, supervisor, receiveTimeout)
 
   protected def actorContext: ActorContext = actorCell
 

akka-actor/src/main/scala/akka/actor/Props.scala

@@ -22,7 +22,6 @@ object Props {
 
   final val defaultRoutedProps: RouterConfig = NoRouter
 
-  final val noHotSwap: Stack[Actor.Receive] = Stack.empty
   final val empty = new Props(() ⇒ new Actor { def receive = Actor.emptyBehavior })
 
   /**

akka-testkit/src/main/scala/akka/testkit/TestActorRef.scala

@@ -41,9 +41,8 @@ class TestActorRef[T <: Actor](
     ref: InternalActorRef,
     props: Props,
     supervisor: InternalActorRef,
-    receiveTimeout: Option[Duration],
-    hotswap: Stack[PartialFunction[Any, Unit]]): ActorCell =
-    new ActorCell(system, ref, props, supervisor, receiveTimeout, hotswap) {
+    receiveTimeout: Option[Duration]): ActorCell =
+    new ActorCell(system, ref, props, supervisor, receiveTimeout) {
       override def autoReceiveMessage(msg: Envelope) {
         msg.message match {
           case InternalGetActor ⇒ sender ! actor