[ClassLoader] made DebugClassLoader idempotent

src/Symfony/Component/ClassLoader/DebugClassLoader.php

@@ -53,7 +53,7 @@ class DebugClassLoader
         }
 
         foreach ($functions as $function) {
-            if (is_array($function) && method_exists($function[0], 'findFile')) {
+            if (is_array($function) && !$function[0] instanceof self && method_exists($function[0], 'findFile')) {
                 $function = array(new static($function[0]), 'loadClass');
             }
 
@@ -104,4 +104,9 @@ class DebugClassLoader
             return true;
         }
     }
+
+    public function getClassFinder()
+    {
+        return $this->classFinder;
+    }
 }

src/Symfony/Component/ClassLoader/Tests/DebugClassLoaderTest.php

@@ -0,0 +1,47 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\ClassLoader\Tests;
+
+use Symfony\Component\ClassLoader\DebugClassLoader;
+use Symfony\Component\ClassLoader\UniversalClassLoader;
+
+class DebugClassLoaderTest extends \PHPUnit_Framework_TestCase
+{
+    private $loader;
+
+    protected function setUp()
+    {
+        $this->loader = new UniversalClassLoader();
+        spl_autoload_register(array($this->loader, 'loadClass'));
+    }
+
+    protected function tearDown()
+    {
+        spl_autoload_unregister(array($this->loader, 'loadClass'));
+    }
+
+    public function testIdempotence()
+    {
+        DebugClassLoader::enable();
+        DebugClassLoader::enable();
+
+        $functions = spl_autoload_functions();
+        foreach ($functions as $function) {
+            if (is_array($function) && $function[0] instanceof DebugClassLoader) {
+                $this->assertNotInstanceOf('Symfony\Component\ClassLoader\DebugClassLoader', $function[0]->getClassFinder());
+                return;
+            }
+        }
+
+        throw new \Exception('DebugClassLoader did not register');
+    }
+}