Trust the server start function to report the port the service started on

Author: ash211

core/src/main/scala/org/apache/spark/HttpServer.scala

@@ -48,7 +48,7 @@ private[spark] class HttpServer(resourceBase: File,
   private var server: Server = null
   private var port: Int = localPort
 
-  private def startOnPort(startPort: Int): Server = {
+  private def startOnPort(startPort: Int): (Server, Int) = {
     val server = new Server()
     val connector = new SocketConnector
     connector.setMaxIdleTime(60*1000)
@@ -79,7 +79,7 @@ private[spark] class HttpServer(resourceBase: File,
     server.start()
     val actualPort = server.getConnectors()(0).getLocalPort()
 
-    server
+    (server, actualPort)
   }
 
   def start() {

core/src/main/scala/org/apache/spark/network/ConnectionManager.scala

@@ -104,7 +104,7 @@ private[spark] class ConnectionManager(port: Int, conf: SparkConf,
 
   private def startService(port: Int) = {
     serverChannel.socket.bind(new InetSocketAddress(port))
-    serverChannel
+    (serverChannel, port)
   }
   PortManager.startWithIncrements(port, 3, startService)
   serverChannel.register(selector, SelectionKey.OP_ACCEPT)

core/src/main/scala/org/apache/spark/network/PortManager.scala

@@ -38,13 +38,12 @@ private[spark] object PortManager extends Logging
    * @throws SparkException When unable to start service in the given number of attempts
    * @return
    */
-  def startWithIncrements[T](startPort: Int, maxRetries: Int, startService: Int => T):
+  def startWithIncrements[T](startPort: Int, maxRetries: Int, startService: Int => (T, Int)):
       (T, Int) = {
     for( offset <- 0 to maxRetries) {
       val tryPort = startPort + offset
       try {
-        val service: T = startService(tryPort)
-        return (service, tryPort)
+        return startService(tryPort)
       } catch {
         case e: java.net.BindException => {
           if (!e.getMessage.contains("Address already in use") ||