From 8cc3c0dd93c9663d1583a6b6ea4bc1214caf713f Mon Sep 17 00:00:00 2001
From: Luca Cavanna <javanna@users.noreply.github.com>
Date: Wed, 31 Jul 2019 17:02:39 +0200
Subject: [PATCH] Remove task null check in TransportAction (#45014)

The task that TaskManager#register returns cannot be null. The method
enforces that it is not null after calling request#createTask. It is
then needless to check for null in the listener later. Also, added the
call to the delegate listener in a finally block, just to make sure.
---
 .../action/support/TransportAction.java       | 24 ++++++++++++-------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/server/src/main/java/org/elasticsearch/action/support/TransportAction.java b/server/src/main/java/org/elasticsearch/action/support/TransportAction.java
index fcb4905b959..a500df5c643 100644
--- a/server/src/main/java/org/elasticsearch/action/support/TransportAction.java
+++ b/server/src/main/java/org/elasticsearch/action/support/TransportAction.java
@@ -64,14 +64,20 @@ public abstract class TransportAction<Request extends ActionRequest, Response ex
         execute(task, request, new ActionListener<Response>() {
             @Override
             public void onResponse(Response response) {
-                taskManager.unregister(task);
-                listener.onResponse(response);
+                try {
+                    taskManager.unregister(task);
+                } finally {
+                    listener.onResponse(response);
+                }
             }
 
             @Override
             public void onFailure(Exception e) {
-                taskManager.unregister(task);
-                listener.onFailure(e);
+                try {
+                    taskManager.unregister(task);
+                } finally {
+                    listener.onFailure(e);
+                }
             }
         });
         return task;
@@ -86,18 +92,20 @@ public abstract class TransportAction<Request extends ActionRequest, Response ex
         execute(task, request, new ActionListener<Response>() {
             @Override
             public void onResponse(Response response) {
-                if (task != null) {
+                try {
                     taskManager.unregister(task);
+                } finally {
+                    listener.onResponse(task, response);
                 }
-                listener.onResponse(task, response);
             }
 
             @Override
             public void onFailure(Exception e) {
-                if (task != null) {
+                try {
                     taskManager.unregister(task);
+                } finally {
+                    listener.onFailure(task, e);
                 }
-                listener.onFailure(task, e);
             }
         });
         return task;