From c061c30a9e50f0250b3e5e5e08d60484daa017b8 Mon Sep 17 00:00:00 2001
From: Tim Nagel <tim@nagel.com.au>
Date: Tue, 10 Jul 2012 14:22:39 +1000
Subject: [PATCH] Router#resolveString should return null instead of empty
 string when $value is null

Closes #4823
---
 src/Symfony/Bundle/FrameworkBundle/Routing/Router.php | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/Symfony/Bundle/FrameworkBundle/Routing/Router.php b/src/Symfony/Bundle/FrameworkBundle/Routing/Router.php
index 3f9b5cf75e..c69ec13066 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Routing/Router.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Routing/Router.php
@@ -114,6 +114,10 @@ class Router extends BaseRouter implements WarmableInterface
     {
         $container = $this->container;
 
+        if (null === $value) {
+            return null;
+        }
+
         $escapedValue = preg_replace_callback('/%%|%([^%\s]+)%/', function ($match) use ($container, $value) {
             // skip %%
             if (!isset($match[1])) {