!clu #3920 Remove deprecated akka.cluster.auto-down

* replaced by akka.cluster.auto-down-unreachable-after

akka-cluster/src/main/resources/reference.conf

@@ -29,9 +29,6 @@ akka {
     # Disable with "off" or specify a duration to enable auto-down.
     auto-down-unreachable-after = off
     
-    # deprecated in 2.3, use 'auto-down-unreachable-after' instead
-    auto-down = off 
-
     # The roles of this member. List of strings, e.g. roles = ["A", "B"].
     # The roles are part of the membership information and can be used by
     # routers or other services to distribute work to certain member types,

akka-cluster/src/main/scala/akka/cluster/Cluster.scala

@@ -101,9 +101,6 @@ class Cluster(val system: ExtendedActorSystem) extends Extension {
 
   logInfo("Starting up...")
 
-  if (settings.AutoDown)
-    log.warning("[akka.cluster.auto-down] setting is replaced by [akka.cluster.auto-down-unreachable-after]")
-
   val failureDetector: FailureDetectorRegistry[Address] = {
     def createFailureDetector(): FailureDetector =
       FailureDetectorLoader.load(settings.FailureDetectorImplementationClass, settings.FailureDetectorConfig, system)

akka-cluster/src/main/scala/akka/cluster/ClusterDaemon.scala

@@ -218,7 +218,7 @@ private[cluster] class ClusterCoreDaemon(publisher: ActorRef) extends Actor with
 
   val cluster = Cluster(context.system)
   import cluster.{ selfAddress, scheduler, failureDetector }
-  import cluster.settings.{ AutoDown ⇒ _, _ }
+  import cluster.settings._
   import cluster.InfoLogger._
 
   protected def selfUniqueAddress = cluster.selfUniqueAddress

akka-cluster/src/main/scala/akka/cluster/ClusterSettings.scala

@@ -58,12 +58,10 @@ final class ClusterSettings(val config: Config, val systemName: String) {
     }
   }
 
-  @deprecated("akka.cluster.auto-down setting is replaced by akka.cluster.auto-down-unreachable-after", "2.3")
-  val AutoDown: Boolean = cc.getBoolean("auto-down")
   val AutoDownUnreachableAfter: Duration = {
     val key = "auto-down-unreachable-after"
     cc.getString(key).toLowerCase match {
-      case "off" ⇒ if (AutoDown) Duration.Zero else Duration.Undefined
+      case "off" ⇒ Duration.Undefined
       case _     ⇒ cc.getMillisDuration(key) requiring (_ >= Duration.Zero, key + " >= 0s, or off")
     }
   }

akka-docs/rst/project/migration-guide-2.3.x-2.4.x.rst

@@ -28,3 +28,4 @@ The following, previously deprecated, features have been removed:
 * akka-transactor
 * durable mailboxes (akka-mailboxes-common, akka-file-mailbox)
 * Cluster.publishCurrentClusterState
+* akka.cluster.auto-down, replaced by akka.cluster.auto-down-unreachable-after in Akka 2.3