#22687 Undefer before terminate

akka-typed/src/main/scala/akka/typed/Behavior.scala

@@ -155,13 +155,9 @@ object Behavior {
     }
 
   @tailrec
-  def undefer[T](deferredBehavior: DeferredBehavior[T], ctx: ActorContext[T]): Behavior[T] = {
-    val behavior = deferredBehavior(ctx)
-
-    behavior match {
-      case innerDeferred: DeferredBehavior[T] @unchecked ⇒ undefer(innerDeferred, ctx)
-      case _ ⇒ behavior
-    }
+  def undefer[T](behavior: Behavior[T], ctx: ActorContext[T]): Behavior[T] = behavior match {
+    case innerDeferred: DeferredBehavior[T] @unchecked ⇒ undefer(innerDeferred(ctx), ctx)
+    case _ ⇒ behavior
   }
 
   /**
@@ -169,7 +165,7 @@ object Behavior {
    * notably the behavior can neither be `Same` nor `Unhandled`. Starting
    * out with a `Stopped` behavior is allowed, though.
    */
-  def validateAsInitial[T](behavior: Behavior[T]): Behavior[T] =
+  def validateAsInitial[T](behavior: BehaSo I get updates every day or so. Bleeding edge, but also works whenever I need it, which is quite rare as well. vior[T]): Behavior[T] =
     behavior match {
       case SameBehavior | UnhandledBehavior ⇒
         throw new IllegalArgumentException(s"cannot use $behavior as initial behavior")
@@ -179,12 +175,8 @@ object Behavior {
   /**
    * Validate the given behavior as initial, initialize it if it is deferred.
    */
-  def preStart[T](behavior: Behavior[T], ctx: ActorContext[T]): Behavior[T] = {
-    validateAsInitial(behavior) match {
-      case d: DeferredBehavior[T] @unchecked ⇒ validateAsInitial(undefer(d, ctx))
-      case x                                 ⇒ x
-    }
-  }
+  def preStart[T](behavior: Behavior[T], ctx: ActorContext[T]): Behavior[T] =
+    validateAsInitial(undefer(behavior, ctx))
 
   /**
    * Returns true if the given behavior is not stopped.
@@ -210,8 +202,8 @@ object Behavior {
 
   private def interpret[T](behavior: Behavior[T], ctx: ActorContext[T], msg: Any): Behavior[T] =
     behavior match {
-      case SameBehavior | UnhandledBehavior ⇒ throw new IllegalArgumentException(s"cannot execute with $behavior as behavior")
-      case _: DeferredBehavior[_]           ⇒ throw new IllegalArgumentException(s"deferred should not be passed to interpreter")
+      case SameBehavior | UnhandledBehavior ⇒ throw new IllegalArgumentException(s"cannot execute with [$behavior] as behavior")
+      case d: DeferredBehavior[_]           ⇒ throw new IllegalArgumentException(s"deferred [$d] should not be passed to interpreter")
       case IgnoreBehavior                   ⇒ SameBehavior.asInstanceOf[Behavior[T]]
       case StoppedBehavior                  ⇒ StoppedBehavior.asInstanceOf[Behavior[T]]
       case EmptyBehavior                    ⇒ UnhandledBehavior.asInstanceOf[Behavior[T]]
@@ -220,10 +212,7 @@ object Behavior {
           case signal: Signal ⇒ ext.management(ctx, signal)
           case msg            ⇒ ext.message(ctx, msg.asInstanceOf[T])
         }
-        possiblyDeferredResult match {
-          case d: DeferredBehavior[T] @unchecked ⇒ undefer(d, ctx)
-          case notDeferred                       ⇒ notDeferred
-        }
+        undefer(possiblyDeferredResult, ctx)
     }
 
 }

akka-typed/src/main/scala/akka/typed/internal/SupervisionMechanics.scala

@@ -4,9 +4,7 @@
 package akka.typed
 package internal
 
-import scala.annotation.{ switch, tailrec }
 import scala.util.control.NonFatal
-import scala.util.control.Exception.Catcher
 import akka.event.Logging
 import akka.typed.Behavior.DeferredBehavior
 
@@ -89,8 +87,10 @@ private[typed] trait SupervisionMechanics[T] {
     val a = behavior
     /*
      * The following order is crucial for things to work properly. Only change this if you're very confident and lucky.
+     *
+     * Do not undefer a DeferredBehavior as that may cause creation side-effects, which we do not want on termination.
      */
-    try if (a ne null) Behavior.canonicalize(Behavior.interpretSignal(a, ctx, PostStop), a, ctx)
+    try if ((a ne null) && !a.isInstanceOf[DeferredBehavior[_]]) Behavior.canonicalize(Behavior.interpretSignal(a, ctx, PostStop), a, ctx)
     catch { case NonFatal(ex) ⇒ publish(Logging.Error(ex, self.path.toString, clazz(a), "failure during PostStop")) }
     finally try tellWatchersWeDied()
     finally try parent.sendSystem(DeathWatchNotification(self, failed))

akka-typed/src/main/scala/akka/typed/patterns/Restarter.scala

@@ -32,15 +32,13 @@ final case class Restarter[T, Thr <: Throwable: ClassTag](initialBehavior: Behav
     else if (b eq behavior) Same
     else {
       b match {
-        case d: DeferredBehavior[_] ⇒ canonical(Behavior.undefer(d.asInstanceOf[DeferredBehavior[T]], ctx), ctx)
+        case d: DeferredBehavior[_] ⇒ canonical(Behavior.undefer(d, ctx), ctx)
         case b                      ⇒ Restarter[T, Thr](initialBehavior, resume)(b)
       }
     }
 
-  private def preStart(b: Behavior[T], ctx: ActorContext[T]): Behavior[T] = b match {
-    case d: DeferredBehavior[_] ⇒ Behavior.undefer(d.asInstanceOf[DeferredBehavior[T]], ctx)
-    case b                      ⇒ b
-  }
+  private def preStart(b: Behavior[T], ctx: ActorContext[T]): Behavior[T] =
+    Behavior.undefer(b, ctx)
 
   override def management(ctx: ActorContext[T], signal: Signal): Behavior[T] = {
     val startedBehavior = preStart(behavior, ctx)