Merge pull request #17888 from akka/wip-17805-clearActorFields-patriknw

=act #17805 Don't change self on restart"

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

@@ -567,7 +567,7 @@ private[akka] class ActorCell(
   protected def create(failure: Option[ActorInitializationException]): Unit = {
     def clearOutActorIfNonNull(): Unit = {
       if (actor != null) {
-        clearActorFields(actor)
+        clearActorFields(actor, recreate = false)
         actor = null // ensure that we know that we failed during creation
       }
     }
@@ -640,8 +640,8 @@ private[akka] class ActorCell(
       throw new IllegalArgumentException("ActorCell has no props field")
   }
 
-  final protected def clearActorFields(actorInstance: Actor): Unit = {
-    setActorFields(actorInstance, context = null, self = system.deadLetters)
+  final protected def clearActorFields(actorInstance: Actor, recreate: Boolean): Unit = {
+    setActorFields(actorInstance, context = null, self = if (recreate) self else system.deadLetters)
     currentMessage = null
     behaviorStack = emptyBehaviorStack
   }

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

@@ -69,7 +69,7 @@ private[akka] trait FaultHandling { this: ActorCell ⇒
           val ex = new PreRestartException(self, e, cause, optionalMessage)
           publish(Error(ex, self.path.toString, clazz(failedActor), e.getMessage))
         } finally {
-          clearActorFields(failedActor)
+          clearActorFields(failedActor, recreate = true)
         }
       }
       assert(mailbox.isSuspended, "mailbox must be suspended during restart, status=" + mailbox.currentStatus)
@@ -217,7 +217,7 @@ private[akka] trait FaultHandling { this: ActorCell ⇒
       if (system.settings.DebugLifecycle)
         publish(Debug(self.path.toString, clazz(a), "stopped"))
 
-      clearActorFields(a)
+      clearActorFields(a, recreate = false)
       clearActorCellFields(this)
       actor = null
     }
@@ -245,7 +245,7 @@ private[akka] trait FaultHandling { this: ActorCell ⇒
           publish(Error(e, self.path.toString, clazz(freshActor), "restarting " + child))
         })
     } catch handleNonFatalOrInterruptedException { e ⇒
-      clearActorFields(actor) // in order to prevent preRestart() from happening again
+      clearActorFields(actor, recreate = false) // in order to prevent preRestart() from happening again
       handleInvokeFailure(survivors, new PostRestartException(self, e, cause))
     }
   }

project/MiMa.scala

@@ -537,7 +537,10 @@ object MiMa extends AutoPlugin {
       FilterAnyProblem("akka.remote.RemoteWatcher$Stats"),
 
       // toString is available on any object, mima is confused due to a generated toString appearing #17722
-      ProblemFilters.exclude[MissingMethodProblem]("akka.japi.Pair.toString")
+      ProblemFilters.exclude[MissingMethodProblem]("akka.japi.Pair.toString"),
+      
+      // #17805
+      ProblemFilters.exclude[MissingMethodProblem]("akka.actor.ActorCell.clearActorFields")
 
      )
   }