made a performance optimization

To benefit from the optimization, you need to change this line from your
autoload.php:

require_once $vendorDir.'/symfony/src/Symfony/Component/HttpFoundation/UniversalClassLoader.php';

to this one:

require_once $vendorDir.'/symfony/src/Symfony/Component/HttpKernel/bootstrap.php';

Notice that if you don't do this change, your app will in fact be slower than before.

src/Symfony/Component/HttpKernel/Kernel.php

@@ -120,8 +120,6 @@ abstract class Kernel implements HttpKernelInterface, \Serializable
             return;
         }
 
-        require_once __DIR__.'/bootstrap.php';
-
         // init bundles
         $this->initializeBundles();
 

src/Symfony/Component/HttpKernel/Resources/bin/packager.php

@@ -23,15 +23,26 @@ if (file_exists(__DIR__.'/../../bootstrap.php')) {
 }
 
 ClassCollectionLoader::load(array(
-    'Symfony\\Component\\HttpKernel\\Bundle\\Bundle',
-    'Symfony\\Component\\HttpKernel\\Bundle\\BundleInterface',
-    'Symfony\\Component\\HttpKernel\\Debug\\ErrorHandler',
-    'Symfony\\Component\\HttpKernel\\ClassCollectionLoader',
-
+    'Symfony\\Component\\DependencyInjection\\ContainerInterface',
     'Symfony\\Component\\DependencyInjection\\Container',
     'Symfony\\Component\\DependencyInjection\\ContainerAwareInterface',
-    'Symfony\\Component\\DependencyInjection\\ContainerInterface',
-    'Symfony\\Component\\DependencyInjection\\ParameterBag\\FrozenParameterBag',
+    'Symfony\\Component\\DependencyInjection\\ContainerAware',
     'Symfony\\Component\\DependencyInjection\\ParameterBag\\ParameterBagInterface',
+    'Symfony\\Component\\DependencyInjection\\ParameterBag\\ParameterBag',
+    'Symfony\\Component\\DependencyInjection\\ParameterBag\\FrozenParameterBag',
+
+    'Symfony\\Component\\HttpKernel\\Bundle\\BundleInterface',
+    'Symfony\\Component\\HttpKernel\\Bundle\\Bundle',
+    'Symfony\\Component\\HttpKernel\\Debug\\ErrorHandler',
+    'Symfony\\Component\\HttpKernel\\ClassCollectionLoader',
+    'Symfony\\Component\\HttpKernel\\HttpKernelInterface',
+    'Symfony\\Component\\HttpKernel\\Kernel',
+
+    'Symfony\\Component\\HttpFoundation\\ParameterBag',
+    'Symfony\\Component\\HttpFoundation\\FileBag',
+    'Symfony\\Component\\HttpFoundation\\ServerBag',
+    'Symfony\\Component\\HttpFoundation\\HeaderBag',
+    'Symfony\\Component\\HttpFoundation\\Request',
+    'Symfony\\Component\\HttpFoundation\\UniversalClassLoader',
 
 ), __DIR__.'/../..', 'bootstrap', false);