only create the routees once they can be looked-up, see #3406

- move the creation of the RoutedActorCell’s route into
  ActorCell.start(); it used to be done in the constructor
- this requires “val route” to turn into a volatile private var

Thanks to Patrik for finding it!

akka-actor-tests/src/test/scala/akka/routing/RouteeCreationSpec.scala

@@ -0,0 +1,51 @@
+/**
+ * Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package akka.routing
+
+import akka.testkit.AkkaSpec
+import akka.actor.Props
+import akka.actor.Actor
+import akka.actor.ActorRef
+import akka.actor.LocalActorRef
+import scala.concurrent.duration._
+
+class RouteeCreationSpec extends AkkaSpec {
+
+  "Creating Routees" must {
+
+    "result in visible routees" in {
+      val N = 100
+      system.actorOf(Props(new Actor {
+        testActor ! system.actorFor(self.path)
+        def receive = Actor.emptyBehavior
+      }).withRouter(RoundRobinRouter(N)))
+      for (i ← 1 to N) {
+        expectMsgType[ActorRef] match {
+          case _: LocalActorRef ⇒ // fine
+          case x                ⇒ fail(s"routee $i was a ${x.getClass}")
+        }
+      }
+    }
+
+    "allow sending to context.parent" in {
+      val N = 100
+      system.actorOf(Props(new Actor {
+        context.parent ! "one"
+        def receive = {
+          case "one" ⇒ testActor forward "two"
+        }
+      }).withRouter(RoundRobinRouter(N)))
+      val gotit = receiveWhile(messages = N) {
+        case "two" ⇒ lastSender.toString
+      }
+      expectNoMsg(100.millis)
+      if (gotit.size != N) {
+        fail(s"got only ${gotit.size} from \n${gotit mkString "\n"}")
+      }
+    }
+
+  }
+
+}

akka-actor/src/main/scala/akka/actor/dungeon/Dispatch.scala

@@ -74,7 +74,7 @@ private[akka] trait Dispatch { this: ActorCell ⇒
   /**
    * Start this cell, i.e. attach it to the dispatcher.
    */
-  final def start(): this.type = {
+  def start(): this.type = {
     // This call is expected to start off the actor by scheduling its mailbox.
     dispatcher.attach(this)
     this

akka-actor/src/main/scala/akka/routing/Routing.scala

@@ -46,7 +46,7 @@ private[akka] object RoutedActorCell {
   }
 }
 
-private[akka] class RoutedActorCell(_system: ActorSystemImpl, _ref: InternalActorRef, _props: Props, _supervisor: InternalActorRef)
+private[akka] final class RoutedActorCell(_system: ActorSystemImpl, _ref: InternalActorRef, _props: Props, _supervisor: InternalActorRef)
   extends ActorCell(
     _system,
     _ref,
@@ -67,7 +67,11 @@ private[akka] class RoutedActorCell(_system: ActorSystemImpl, _ref: InternalActo
   private var _routeeProvider: RouteeProvider = _
   def routeeProvider = _routeeProvider
 
-  val route = {
+  @volatile
+  private var _route: Route = _
+  def route = _route
+
+  private def startRoute() {
     val routeeProps = _props.withRouter(NoRouter)
     _routeeProvider = routerConfig.createRouteeProvider(this, routeeProps)
     val r = routerConfig.createRoute(routeeProvider)
@@ -76,7 +80,13 @@ private[akka] class RoutedActorCell(_system: ActorSystemImpl, _ref: InternalActo
       if (resizer.isTimeForResize(resizeCounter.getAndIncrement()))
         resizer.resize(routeeProvider)
     }
-    r
+    _route = r
+  }
+
+  override def start(): this.type = {
+    startRoute()
+    // create the routees before scheduling the Router actor
+    super.start()
   }
 
   /*