Ticket #39647: patch.39647

Index: wp-includes/functions.php
===================================================================
--- wp-includes/functions.php   (revision 45555)
+++ wp-includes/functions.php   (working copy)
@@ -3110,6 +3110,10 @@
                        header( 'Content-Type: text/html; charset=utf-8' );
                        status_header( $r['response'] );
                        nocache_headers();
+            
+            if( isset( $r['last_error_message'] ) && $r['last_error_message']) {
+                header( 'X-WP-lasterror-message: '.$r['last_error_message'] );
+            }
                }
 
                $text_direction = $r['text_direction'];
@@ -3509,6 +3513,12 @@
 
        $args = wp_parse_args( $args, $defaults );
 
+       
+    // Early
+    if( $message instanceof WP_Error && isset( $message->error_data['internal_server_error']['error']['message'] ) ) {
+        $args['last_error_message'] = $message->error_data['internal_server_error']['error']['message'];
+    }
+           
        if ( function_exists( 'is_wp_error' ) && is_wp_error( $message ) ) {
                if ( ! empty( $message->errors ) ) {
                        $errors = array();
@@ -3533,6 +3543,9 @@
                                $title = $errors[0]['data']['title'];
                        }
 
+            if( isset( $errors[0][0] ) ) {
+                $args['last_error'] = array_values( $errors[0][0] );
+            }
                        unset( $errors[0] );
                        $args['additional_errors'] = array_values( $errors );
                } else {