get the root reason when available

Author: Massimo Galbusera

CHANGELOG.md

@@ -11,6 +11,7 @@ All notable changes to this project will be documented in this file based on the
 
 ### Improvements
 - Set PHP 7.0 as default development version
+- Get the root reason from Elasticsearch's error JSON, when available [#1111](https://github.com/ruflin/Elastica/pull/1111)
 
 ## [3.2.1](https://github.com/ruflin/Elastica/compare/3.2.0...3.2.1)
 

lib/Elastica/Response.php

@@ -95,13 +95,18 @@ public function getError()
             return $error;
         }
 
+        $rootError = $error;
         if (isset($error['root_cause'][0])) {
-            $error = $error['root_cause'][0];
+            $rootError = $error['root_cause'][0];
         }
 
-        $message = $error['reason'];
-        if (isset($error['index'])) {
-            $message .= ' [index: '.$error['index'].']';
+        $message = $rootError['reason'];
+        if (isset($rootError['index'])) {
+            $message .= ' [index: '.$rootError['index'].']';
+        }
+
+        if (isset($error['reason']) && $rootError['reason'] != $error['reason']) {
+            $message .= ' [reason: '.$error['reason'].']';
         }
 
         return $message;