From d83d65a312e9f7d45ecbfa50494b6bc6de6589fa Mon Sep 17 00:00:00 2001
From: Tobias Schultze <webmaster@tubo-world.de>
Date: Thu, 12 Jul 2012 18:43:06 +0300
Subject: [PATCH] fix another '0' problem

---
 src/Symfony/Component/HttpFoundation/JsonResponse.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Symfony/Component/HttpFoundation/JsonResponse.php b/src/Symfony/Component/HttpFoundation/JsonResponse.php
index 331ff400f7..43ade8ffaf 100644
--- a/src/Symfony/Component/HttpFoundation/JsonResponse.php
+++ b/src/Symfony/Component/HttpFoundation/JsonResponse.php
@@ -52,7 +52,7 @@ class JsonResponse extends Response
      */
     public function setCallback($callback = null)
     {
-        if ($callback) {
+        if (null !== $callback) {
             // taken from http://www.geekality.net/2011/08/03/valid-javascript-identifier/
             $pattern = '/^[$_\p{L}][$_\p{L}\p{Mn}\p{Mc}\p{Nd}\p{Pc}\x{200C}\x{200D}]*+$/u';
             $parts = explode('.', $callback);
@@ -95,7 +95,7 @@ class JsonResponse extends Response
      */
     protected function update()
     {
-        if ($this->callback) {
+        if (null !== $this->callback) {
             // Not using application/javascript for compatibility reasons with older browsers.
             $this->headers->set('Content-Type', 'text/javascript', true);