add ActorRefProvider.getDefaultAddress, see #2732

- use it in ConsistentHashingRouter instead of relying on
  provider.rootPath.address
- remove transport.address from RemoteActorRefProvider.rootPath

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

@@ -146,6 +146,11 @@ trait ActorRefProvider {
    * attempt is made to verify actual reachability).
    */
   def getExternalAddressFor(addr: Address): Option[Address]
+
+  /**
+   * Obtain the external address of the default transport.
+   */
+  def getDefaultAddress: Address
 }
 
 /**
@@ -597,4 +602,6 @@ class LocalActorRefProvider(
   }
 
   def getExternalAddressFor(addr: Address): Option[Address] = if (addr == rootPath.address) Some(addr) else None
+
+  def getDefaultAddress: Address = rootPath.address
 }

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

@@ -237,7 +237,7 @@ trait ConsistentHashingLike { this: RouterConfig ⇒
     }
 
     val log = Logging(routeeProvider.context.system, routeeProvider.context.self)
-    val selfAddress = routeeProvider.context.system.asInstanceOf[ExtendedActorSystem].provider.rootPath.address
+    val selfAddress = routeeProvider.context.system.asInstanceOf[ExtendedActorSystem].provider.getDefaultAddress
     val vnodes =
       if (virtualNodesFactor == 0) routeeProvider.context.system.settings.DefaultVirtualNodesFactor
       else virtualNodesFactor

akka-remote/src/main/scala/akka/remote/RemoteActorRefProvider.scala

@@ -32,9 +32,7 @@ class RemoteActorRefProvider(
   private var _log = local.log
   def log: LoggingAdapter = _log
 
-  @volatile
-  private var _rootPath = local.rootPath
-  override def rootPath: ActorPath = _rootPath
+  override def rootPath: ActorPath = local.rootPath
   override def deadLetters: InternalActorRef = local.deadLetters
 
   // these are only available after init()
@@ -63,7 +61,7 @@ class RemoteActorRefProvider(
   def init(system: ActorSystemImpl): Unit = {
     local.init(system)
 
-    _remoteDaemon = new RemoteSystemDaemon(system, local.rootPath / "remote", rootGuardian, log, untrustedMode = remoteSettings.UntrustedMode)
+    _remoteDaemon = new RemoteSystemDaemon(system, rootPath / "remote", rootGuardian, log, untrustedMode = remoteSettings.UntrustedMode)
     local.registerExtraNames(Map(("remote", remoteDaemon)))
 
     _serialization = SerializationExtension(system)
@@ -84,8 +82,6 @@ class RemoteActorRefProvider(
     // this enables reception of remote requests
     _transport.start()
 
-    _rootPath = RootActorPath(local.rootPath.address.copy(host = transport.address.host, port = transport.address.port))
-
     val remoteClientLifeCycleHandler = system.systemActorOf(Props(new Actor {
       def receive = {
         case RemoteClientError(cause, remote, address) ⇒ remote.shutdownClientConnection(address)
@@ -201,8 +197,10 @@ class RemoteActorRefProvider(
     }
   }
 
+  def getDefaultAddress: Address = transport.address
+
   private def isSelfAddress(address: Address): Boolean =
-    address == local.rootPath.address || address == rootPath.address || address == transport.address
+    address == rootPath.address || address == transport.address
 
 }