diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
index 885752b89da6..7faeac7ff586 100644
--- a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
+++ b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
@@ -91,10 +91,10 @@ private function addFormSection(ArrayNodeDefinition $rootNode)
             ->children()
                 ->arrayNode('form')
                     ->info('form configuration')
-                    ->canBeDisabled()
+                    ->canBeEnabled()
                 ->end()
                 ->arrayNode('csrf_protection')
-                    ->canBeDisabled()
+                    ->canBeEnabled()
                     ->children()
                         ->scalarNode('field_name')->defaultValue('_token')->end()
                     ->end()
@@ -109,7 +109,7 @@ private function addEsiSection(ArrayNodeDefinition $rootNode)
             ->children()
                 ->arrayNode('esi')
                     ->info('esi configuration')
-                    ->canBeDisabled()
+                    ->canBeEnabled()
                 ->end()
             ->end()
         ;
@@ -121,7 +121,7 @@ private function addRouterProxySection(ArrayNodeDefinition $rootNode)
             ->children()
                 ->arrayNode('router_proxy')
                     ->info('proxy configuration for the HTTP content renderer')
-                    ->canBeDisabled()
+                    ->canBeEnabled()
                     ->children()
                         ->scalarNode('path')->defaultValue('/_proxy')->end()
                     ->end()
@@ -136,7 +136,7 @@ private function addProfilerSection(ArrayNodeDefinition $rootNode)
             ->children()
                 ->arrayNode('profiler')
                     ->info('profiler configuration')
-                    ->canBeDisabled()
+                    ->canBeEnabled()
                     ->children()
                         ->booleanNode('only_exceptions')->defaultFalse()->end()
                         ->booleanNode('only_master_requests')->defaultFalse()->end()
@@ -176,8 +176,10 @@ private function addRouterSection(ArrayNodeDefinition $rootNode)
                         ->scalarNode('https_port')->defaultValue(443)->end()
                         ->scalarNode('strict_requirements')
                             ->info(
-                                'set to false to disable exceptions when a route is '.
-                                'generated with invalid parameters (and return null instead)'
+                                "set to true to throw an exception when a parameter does not match the requirements\n".
+                                "set to false to disable exceptions when a parameter does not match the requirements (and return null instead)\n".
+                                "set to null to disable parameter checks against requirements\n".
+                                "'true' is the preferred configuration in development mode, while 'false' or 'null' might be preferred in production"
                             )
                             ->defaultTrue()
                         ->end()
@@ -367,7 +369,7 @@ private function addTranslatorSection(ArrayNodeDefinition $rootNode)
             ->children()
                 ->arrayNode('translator')
                     ->info('translator configuration')
-                    ->canBeDisabled()
+                    ->canBeEnabled()
                     ->children()
                         ->scalarNode('fallback')->defaultValue('en')->end()
                     ->end()
@@ -382,7 +384,7 @@ private function addValidationSection(ArrayNodeDefinition $rootNode)
             ->children()
                 ->arrayNode('validation')
                     ->info('validation configuration')
-                    ->canBeDisabled()
+                    ->canBeEnabled()
                     ->children()
                         ->scalarNode('cache')->end()
                         ->booleanNode('enable_annotations')->defaultFalse()->end()
diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php
index 958c2ce35065..9c04a3b284e5 100644
--- a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php
+++ b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php
@@ -81,39 +81,25 @@ public function load(array $configs, ContainerBuilder $container)
             $this->registerSessionConfiguration($config['session'], $container, $loader);
         }
 
-        if (isset($config['form']) && !empty($config['form']['enabled'])) {
+        if ($this->isConfigEnabled($container, $config['form'])) {
             $this->registerFormConfiguration($config, $container, $loader);
             $config['validation']['enabled'] = true;
         }
 
-        if (!empty($config['validation']['enabled'])) {
-            $this->registerValidationConfiguration($config['validation'], $container, $loader);
-        }
-
-        if (isset($config['esi'])) {
-            $this->registerEsiConfiguration($config['esi'], $loader);
-        }
-
-        if (isset($config['router_proxy'])) {
-            $this->registerRouterProxyConfiguration($config['router_proxy'], $container, $loader);
+        if (isset($config['templating'])) {
+            $this->registerTemplatingConfiguration($config['templating'], $config['ide'], $container, $loader);
         }
 
-        if (isset($config['profiler'])) {
-            $this->registerProfilerConfiguration($config['profiler'], $container, $loader);
-        }
+        $this->registerValidationConfiguration($config['validation'], $container, $loader);
+        $this->registerEsiConfiguration($config['esi'], $container, $loader);
+        $this->registerRouterProxyConfiguration($config['router_proxy'], $container, $loader);
+        $this->registerProfilerConfiguration($config['profiler'], $container, $loader);
+        $this->registerTranslatorConfiguration($config['translator'], $container);
 
         if (isset($config['router'])) {
             $this->registerRouterConfiguration($config['router'], $container, $loader);
         }
 
-        if (isset($config['templating'])) {
-            $this->registerTemplatingConfiguration($config['templating'], $config['ide'], $container, $loader);
-        }
-
-        if (isset($config['translator'])) {
-            $this->registerTranslatorConfiguration($config['translator'], $container);
-        }
-
         $this->registerAnnotationsConfiguration($config['annotations'], $container, $loader);
 
         $this->addClassesToCompile(array(
@@ -161,7 +147,7 @@ public function load(array $configs, ContainerBuilder $container)
     private function registerFormConfiguration($config, ContainerBuilder $container, XmlFileLoader $loader)
     {
         $loader->load('form.xml');
-        if (isset($config['csrf_protection'])) {
+        if ($this->isConfigEnabled($container, $config['csrf_protection'])) {
             if (!isset($config['session'])) {
                 throw new \LogicException('CSRF protection needs that sessions are enabled.');
             }
@@ -170,36 +156,44 @@ private function registerFormConfiguration($config, ContainerBuilder $container,
             }
             $loader->load('form_csrf.xml');
 
-            $container->setParameter('form.type_extension.csrf.enabled', $config['csrf_protection']['enabled']);
+            $container->setParameter('form.type_extension.csrf.enabled', true);
             $container->setParameter('form.type_extension.csrf.field_name', $config['csrf_protection']['field_name']);
+        } else {
+            $container->setParameter('form.type_extension.csrf.enabled', false);
         }
     }
 
     /**
      * Loads the ESI configuration.
      *
-     * @param array         $config An ESI configuration array
-     * @param XmlFileLoader $loader An XmlFileLoader instance
+     * @param array            $config A proxy configuration array
+     * @param ContainerBuilder $container A ContainerBuilder instance
+     * @param XmlFileLoader    $loader An XmlFileLoader instance
      */
-    private function registerEsiConfiguration(array $config, XmlFileLoader $loader)
+    private function registerEsiConfiguration(array $config, ContainerBuilder $container, XmlFileLoader $loader)
     {
-        if (!empty($config['enabled'])) {
-            $loader->load('esi.xml');
+        if (!$this->isConfigEnabled($container, $config)) {
+            return;
         }
+
+        $loader->load('esi.xml');
     }
 
     /**
      * Loads the router proxy configuration.
      *
-     * @param array         $config A proxy configuration array
-     * @param XmlFileLoader $loader An XmlFileLoader instance
+     * @param array            $config A proxy configuration array
+     * @param ContainerBuilder $container A ContainerBuilder instance
+     * @param XmlFileLoader    $loader An XmlFileLoader instance
      */
     private function registerRouterProxyConfiguration(array $config, ContainerBuilder $container, XmlFileLoader $loader)
     {
-        if (!empty($config['enabled'])) {
-            $loader->load('proxy.xml');
-            $container->setParameter('http_content_renderer.proxy_path', $config['path']);
+        if (!$this->isConfigEnabled($container, $config)) {
+            return;
         }
+
+        $loader->load('proxy.xml');
+        $container->setParameter('http_content_renderer.proxy_path', $config['path']);
     }
 
     /**
@@ -258,7 +252,7 @@ private function registerProfilerConfiguration(array $config, ContainerBuilder $
             }
         }
 
-        if (!$config['enabled']) {
+        if (!$this->isConfigEnabled($container, $config)) {
             $container->getDefinition('profiler')->addMethodCall('disable', array());
         }
     }
@@ -530,61 +524,63 @@ private function createPackageDefinition(ContainerBuilder $container, array $htt
      */
     private function registerTranslatorConfiguration(array $config, ContainerBuilder $container)
     {
-        if (!empty($config['enabled'])) {
-            // Use the "real" translator instead of the identity default
-            $container->setAlias('translator', 'translator.default');
-            $translator = $container->findDefinition('translator.default');
-            $translator->addMethodCall('setFallbackLocale', array($config['fallback']));
-
-            // Discover translation directories
-            $dirs = array();
-            if (class_exists('Symfony\Component\Validator\Validator')) {
-                $r = new \ReflectionClass('Symfony\Component\Validator\Validator');
-
-                $dirs[] = dirname($r->getFilename()).'/Resources/translations';
-            }
-            if (class_exists('Symfony\Component\Form\Form')) {
-                $r = new \ReflectionClass('Symfony\Component\Form\Form');
+        if (!$this->isConfigEnabled($container, $config)) {
+            return;
+        }
 
-                $dirs[] = dirname($r->getFilename()).'/Resources/translations';
-            }
-            if (class_exists('Symfony\Component\Security\Core\Exception\AuthenticationException')) {
-                $r = new \ReflectionClass('Symfony\Component\Security\Core\Exception\AuthenticationException');
+        // Use the "real" translator instead of the identity default
+        $container->setAlias('translator', 'translator.default');
+        $translator = $container->findDefinition('translator.default');
+        $translator->addMethodCall('setFallbackLocale', array($config['fallback']));
 
-                $dirs[] = dirname($r->getFilename()).'/../../Resources/translations';
-            }
-            $overridePath = $container->getParameter('kernel.root_dir').'/Resources/%s/translations';
-            foreach ($container->getParameter('kernel.bundles') as $bundle => $class) {
-                $reflection = new \ReflectionClass($class);
-                if (is_dir($dir = dirname($reflection->getFilename()).'/Resources/translations')) {
-                    $dirs[] = $dir;
-                }
-                if (is_dir($dir = sprintf($overridePath, $bundle))) {
-                    $dirs[] = $dir;
-                }
+        // Discover translation directories
+        $dirs = array();
+        if (class_exists('Symfony\Component\Validator\Validator')) {
+            $r = new \ReflectionClass('Symfony\Component\Validator\Validator');
+
+            $dirs[] = dirname($r->getFilename()).'/Resources/translations';
+        }
+        if (class_exists('Symfony\Component\Form\Form')) {
+            $r = new \ReflectionClass('Symfony\Component\Form\Form');
+
+            $dirs[] = dirname($r->getFilename()).'/Resources/translations';
+        }
+        if (class_exists('Symfony\Component\Security\Core\Exception\AuthenticationException')) {
+            $r = new \ReflectionClass('Symfony\Component\Security\Core\Exception\AuthenticationException');
+
+            $dirs[] = dirname($r->getFilename()).'/../../Resources/translations';
+        }
+        $overridePath = $container->getParameter('kernel.root_dir').'/Resources/%s/translations';
+        foreach ($container->getParameter('kernel.bundles') as $bundle => $class) {
+            $reflection = new \ReflectionClass($class);
+            if (is_dir($dir = dirname($reflection->getFilename()).'/Resources/translations')) {
+                $dirs[] = $dir;
             }
-            if (is_dir($dir = $container->getParameter('kernel.root_dir').'/Resources/translations')) {
+            if (is_dir($dir = sprintf($overridePath, $bundle))) {
                 $dirs[] = $dir;
             }
+        }
+        if (is_dir($dir = $container->getParameter('kernel.root_dir').'/Resources/translations')) {
+            $dirs[] = $dir;
+        }
 
-            // Register translation resources
-            if ($dirs) {
-                foreach ($dirs as $dir) {
-                    $container->addResource(new DirectoryResource($dir));
-                }
-                $finder = Finder::create()
-                    ->files()
-                    ->filter(function (\SplFileInfo $file) {
-                        return 2 === substr_count($file->getBasename(), '.') && preg_match('/\.\w+$/', $file->getBasename());
-                    })
-                    ->in($dirs)
-                ;
-
-                foreach ($finder as $file) {
-                    // filename is domain.locale.format
-                    list($domain, $locale, $format) = explode('.', $file->getBasename(), 3);
-                    $translator->addMethodCall('addResource', array($format, (string) $file, $locale, $domain));
-                }
+        // Register translation resources
+        if ($dirs) {
+            foreach ($dirs as $dir) {
+                $container->addResource(new DirectoryResource($dir));
+            }
+            $finder = Finder::create()
+                ->files()
+                ->filter(function (\SplFileInfo $file) {
+                    return 2 === substr_count($file->getBasename(), '.') && preg_match('/\.\w+$/', $file->getBasename());
+                })
+                ->in($dirs)
+            ;
+
+            foreach ($finder as $file) {
+                // filename is domain.locale.format
+                list($domain, $locale, $format) = explode('.', $file->getBasename(), 3);
+                $translator->addMethodCall('addResource', array($format, (string) $file, $locale, $domain));
             }
         }
     }
@@ -598,6 +594,10 @@ private function registerTranslatorConfiguration(array $config, ContainerBuilder
      */
     private function registerValidationConfiguration(array $config, ContainerBuilder $container, XmlFileLoader $loader)
     {
+        if (!$this->isConfigEnabled($container, $config)) {
+            return;
+        }
+
         $loader->load('validator.xml');
 
         $container->setParameter('validator.translation_domain', $config['translation_domain']);
diff --git a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/ConfigurationTest.php b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/ConfigurationTest.php
index 77670cc005c0..7f40dffd49be 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/ConfigurationTest.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/ConfigurationTest.php
@@ -16,46 +16,41 @@
 
 class ConfigurationTest extends \PHPUnit_Framework_TestCase
 {
-    /**
-     * @dataProvider getTestConfigTreeData
-     */
-    public function testConfigTree($options, $results)
+    public function testDefaultConfig()
     {
         $processor = new Processor();
-        $configuration = new Configuration(array());
-        $config = $processor->processConfiguration($configuration, array($options));
+        $config = $processor->processConfiguration(new Configuration(), array(array('secret' => 's3cr3t')));
 
-        $this->assertEquals($results, $config);
-    }
-
-    public function getTestConfigTreeData()
-    {
-        return array(
-            array(array('secret' => 's3cr3t'), array('secret' => 's3cr3t', 'trusted_proxies' => array(), 'trust_proxy_headers' => false, 'ide' => NULL, 'annotations' => array('cache' => 'file', 'file_cache_dir' => '%kernel.cache_dir%/annotations', 'debug' => '%kernel.debug%'), 'default_locale' => 'en', 'charset' => null)),
+        $this->assertEquals(
+            array_merge(array('secret' => 's3cr3t'), self::getBundleDefaultConfig()),
+            $config
         );
     }
 
     /**
      * @dataProvider getTestValidTrustedProxiesData
      */
-    public function testValidTrustedProxies($options, $results)
+    public function testValidTrustedProxies($trustedProxies, $processedProxies)
     {
         $processor = new Processor();
         $configuration = new Configuration(array());
-        $config = $processor->processConfiguration($configuration, array($options));
+        $config = $processor->processConfiguration($configuration, array(array(
+            'secret'          => 's3cr3t',
+            'trusted_proxies' => $trustedProxies
+        )));
 
-        $this->assertEquals($results, $config);
+        $this->assertEquals($processedProxies, $config['trusted_proxies']);
     }
 
     public function getTestValidTrustedProxiesData()
     {
         return array(
-            array(array('secret' => 's3cr3t', 'trusted_proxies' => array('127.0.0.1')), array('secret' => 's3cr3t', 'trusted_proxies' => array('127.0.0.1'), 'trust_proxy_headers' => false, 'ide' => NULL, 'annotations' => array('cache' => 'file', 'file_cache_dir' => '%kernel.cache_dir%/annotations', 'debug' => '%kernel.debug%'), 'default_locale' => 'en', 'charset' => null)),
-            array(array('secret' => 's3cr3t', 'trusted_proxies' => array('::1')), array('secret' => 's3cr3t', 'trusted_proxies' => array('::1'), 'trust_proxy_headers' => false, 'ide' => NULL, 'annotations' => array('cache' => 'file', 'file_cache_dir' => '%kernel.cache_dir%/annotations', 'debug' => '%kernel.debug%'), 'default_locale' => 'en', 'charset' => null)),
-            array(array('secret' => 's3cr3t', 'trusted_proxies' => array('127.0.0.1', '::1')), array('secret' => 's3cr3t', 'trusted_proxies' => array('127.0.0.1', '::1'), 'trust_proxy_headers' => false, 'ide' => NULL, 'annotations' => array('cache' => 'file', 'file_cache_dir' => '%kernel.cache_dir%/annotations', 'debug' => '%kernel.debug%'), 'default_locale' => 'en', 'charset' => null)),
-            array(array('secret' => 's3cr3t', 'trusted_proxies' => null), array('secret' => 's3cr3t', 'trusted_proxies' => array(), 'trust_proxy_headers' => false, 'ide' => NULL, 'annotations' => array('cache' => 'file', 'file_cache_dir' => '%kernel.cache_dir%/annotations', 'debug' => '%kernel.debug%'), 'default_locale' => 'en', 'charset' => null)),
-            array(array('secret' => 's3cr3t', 'trusted_proxies' => false), array('secret' => 's3cr3t', 'trusted_proxies' => array(), 'trust_proxy_headers' => false, 'ide' => NULL, 'annotations' => array('cache' => 'file', 'file_cache_dir' => '%kernel.cache_dir%/annotations', 'debug' => '%kernel.debug%'), 'default_locale' => 'en', 'charset' => null)),
-            array(array('secret' => 's3cr3t', 'trusted_proxies' => array()), array('secret' => 's3cr3t', 'trusted_proxies' => array(), 'trust_proxy_headers' => false, 'ide' => NULL, 'annotations' => array('cache' => 'file', 'file_cache_dir' => '%kernel.cache_dir%/annotations', 'debug' => '%kernel.debug%'), 'default_locale' => 'en', 'charset' => null)),
+            array(array('127.0.0.1'), array('127.0.0.1')),
+            array(array('::1'), array('::1')),
+            array(array('127.0.0.1', '::1'), array('127.0.0.1', '::1')),
+            array(null, array()),
+            array(false, array()),
+            array(array(), array()),
         );
     }
 
@@ -66,7 +61,12 @@ public function testInvalidTypeTrustedProxies()
     {
         $processor = new Processor();
         $configuration = new Configuration(array());
-        $config = $processor->processConfiguration($configuration, array(array('secret' => 's3cr3t', 'trusted_proxies' => 'Not an IP address')));
+        $processor->processConfiguration($configuration, array(
+            array(
+                'secret' => 's3cr3t',
+                'trusted_proxies' => 'Not an IP address'
+            )
+        ));
     }
 
     /**
@@ -76,6 +76,55 @@ public function testInvalidValueTrustedProxies()
     {
         $processor = new Processor();
         $configuration = new Configuration(array());
-        $config = $processor->processConfiguration($configuration, array(array('secret' => 's3cr3t', 'trusted_proxies' => array('Not an IP address'))));
+        $processor->processConfiguration($configuration, array(
+            array(
+                'secret' => 's3cr3t',
+                'trusted_proxies' => array('Not an IP address')
+            )
+        ));
+    }
+
+    protected static function getBundleDefaultConfig()
+    {
+        return array(
+            'charset'             => null,
+            'trust_proxy_headers' => false,
+            'trusted_proxies'     => array(),
+            'ide'                 => null,
+            'default_locale'      => 'en',
+            'form'                => array('enabled' => false),
+            'csrf_protection'     => array(
+                'enabled'    => false,
+                'field_name' => '_token',
+            ),
+            'esi'                 => array('enabled' => false),
+            'router_proxy'        => array(
+                'enabled' => false,
+                'path'    => '/_proxy',
+            ),
+            'profiler'            => array(
+                'enabled'              => false,
+                'only_exceptions'      => false,
+                'only_master_requests' => false,
+                'dsn'                  => 'file:%kernel.cache_dir%/profiler',
+                'username'             => '',
+                'password'             => '',
+                'lifetime'             => 86400,
+            ),
+            'translator'          => array(
+                'enabled'  => false,
+                'fallback' => 'en',
+            ),
+            'validation'          => array(
+                'enabled'            => false,
+                'enable_annotations' => false,
+                'translation_domain' => 'validators',
+            ),
+            'annotations'         => array(
+                'cache'          => 'file',
+                'file_cache_dir' => '%kernel.cache_dir%/annotations',
+                'debug'          => '%kernel.debug%',
+            ),
+        );
     }
 }
diff --git a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/php/validation_annotations.php b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/php/validation_annotations.php
index 75c8f48d49b5..d0c1fdab52d9 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/php/validation_annotations.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/php/validation_annotations.php
@@ -3,7 +3,7 @@
 $container->loadFromExtension('framework', array(
     'secret' => 's3cr3t',
     'validation' => array(
-        'enabled'     => true,
+        'enabled'            => true,
         'enable_annotations' => true,
     ),
 ));
diff --git a/src/Symfony/Component/Config/CHANGELOG.md b/src/Symfony/Component/Config/CHANGELOG.md
index 1478ca1403ef..59b30a3a7a6d 100644
--- a/src/Symfony/Component/Config/CHANGELOG.md
+++ b/src/Symfony/Component/Config/CHANGELOG.md
@@ -4,6 +4,9 @@ CHANGELOG
 2.2.0
 -----
 
+ * added ArrayNodeDefinition::canBeEnabled() and ArrayNodeDefinition::canBeDisabled()
+   to ease configuration when some sections are respectively disabled / enabled
+   by default.
  * added a `normalizeKeys()` method for array nodes (to avoid key normalization)
  * added numerical type handling for config definitions
  * added convenience methods for optional configuration sections to ArrayNodeDefinition
diff --git a/src/Symfony/Component/Config/Definition/Builder/ArrayNodeDefinition.php b/src/Symfony/Component/Config/Definition/Builder/ArrayNodeDefinition.php
index f40a934d82b8..4db15480dc24 100644
--- a/src/Symfony/Component/Config/Definition/Builder/ArrayNodeDefinition.php
+++ b/src/Symfony/Component/Config/Definition/Builder/ArrayNodeDefinition.php
@@ -214,16 +214,32 @@ public function canBeUnset($allow = true)
     /**
      * Adds an "enabled" boolean to enable the current section.
      *
-     * By default, the section is disabled.
+     * By default, the section is disabled. If any configuration is specified then
+     * the node will be automatically enabled:
+     *
+     * enableableArrayNode: {enabled: true, ...}   # The config is enabled & default values get overridden
+     * enableableArrayNode: ~                      # The config is enabled & use the default values
+     * enableableArrayNode: true                   # The config is enabled & use the default values
+     * enableableArrayNode: {other: value, ...}    # The config is enabled & default values get overridden
+     * enableableArrayNode: {enabled: false, ...}  # The config is disabled
+     * enableableArrayNode: false                  # The config is disabled
      *
      * @return ArrayNodeDefinition
      */
     public function canBeEnabled()
     {
         $this
+            ->addDefaultsIfNotSet()
             ->treatFalseLike(array('enabled' => false))
             ->treatTrueLike(array('enabled' => true))
             ->treatNullLike(array('enabled' => true))
+            ->beforeNormalization()
+                ->ifArray()
+                ->then(function($v) {
+                    $v['enabled'] = isset($v['enabled']) ? $v['enabled'] : true;
+                    return $v;
+                })
+            ->end()
             ->children()
                 ->booleanNode('enabled')
                     ->defaultFalse()
@@ -242,6 +258,7 @@ public function canBeEnabled()
     public function canBeDisabled()
     {
         $this
+            ->addDefaultsIfNotSet()
             ->treatFalseLike(array('enabled' => false))
             ->treatTrueLike(array('enabled' => true))
             ->treatNullLike(array('enabled' => true))
diff --git a/src/Symfony/Component/Config/Definition/Processor.php b/src/Symfony/Component/Config/Definition/Processor.php
index 058c3bed34ec..025e69378f94 100644
--- a/src/Symfony/Component/Config/Definition/Processor.php
+++ b/src/Symfony/Component/Config/Definition/Processor.php
@@ -79,18 +79,19 @@ public static function normalizeConfig($config, $key, $plural = null)
             $plural = $key.'s';
         }
 
-        $values = array();
         if (isset($config[$plural])) {
-            $values = $config[$plural];
-        } elseif (isset($config[$key])) {
+            return $config[$plural];
+        }
+
+        if (isset($config[$key])) {
             if (is_string($config[$key]) || !is_int(key($config[$key]))) {
                 // only one
-                $values = array($config[$key]);
-            } else {
-                $values = $config[$key];
+                return  array($config[$key]);
             }
+
+            return  $config[$key];
         }
 
-        return $values;
+        return array();
     }
 }
diff --git a/src/Symfony/Component/Config/Tests/Definition/ArrayNodeTest.php b/src/Symfony/Component/Config/Tests/Definition/ArrayNodeTest.php
index 27445ea339f2..6d241cad5725 100644
--- a/src/Symfony/Component/Config/Tests/Definition/ArrayNodeTest.php
+++ b/src/Symfony/Component/Config/Tests/Definition/ArrayNodeTest.php
@@ -25,19 +25,13 @@ public function testNormalizeThrowsExceptionWhenFalseIsNotAllowed()
     }
 
     /**
-     * normalize() should protect against child values with no corresponding node
+     * @expectedException Symfony\Component\Config\Definition\Exception\InvalidConfigurationException
+     * @expectedExceptionMessage Unrecognized options "foo" under "root"
      */
     public function testExceptionThrownOnUnrecognizedChild()
     {
         $node = new ArrayNode('root');
-
-        try {
-            $node->normalize(array('foo' => 'bar'));
-            $this->fail('An exception should have been throw for a bad child node');
-        } catch (\Exception $e) {
-            $this->assertInstanceOf('Symfony\Component\Config\Definition\Exception\InvalidConfigurationException', $e);
-            $this->assertEquals('Unrecognized options "foo" under "root"', $e->getMessage());
-        }
+        $node->normalize(array('foo' => 'bar'));
     }
 
     /**
diff --git a/src/Symfony/Component/Config/Tests/Definition/Builder/ArrayNodeDefinitionTest.php b/src/Symfony/Component/Config/Tests/Definition/Builder/ArrayNodeDefinitionTest.php
index 4510da5df042..06dacf2ab8cb 100644
--- a/src/Symfony/Component/Config/Tests/Definition/Builder/ArrayNodeDefinitionTest.php
+++ b/src/Symfony/Component/Config/Tests/Definition/Builder/ArrayNodeDefinitionTest.php
@@ -12,6 +12,7 @@
 namespace Symfony\Component\Config\Tests\Definition\Builder;
 
 use Symfony\Component\Config\Definition\Builder\ArrayNodeDefinition;
+use Symfony\Component\Config\Definition\Processor;
 use Symfony\Component\Config\Definition\Builder\ScalarNodeDefinition;
 use Symfony\Component\Config\Definition\Exception\InvalidDefinitionException;
 
@@ -62,7 +63,10 @@ public function providePrototypeNodeSpecificCalls()
     public function testConcreteNodeSpecificOption()
     {
         $node = new ArrayNodeDefinition('root');
-        $node->addDefaultsIfNotSet()->prototype('array');
+        $node
+            ->addDefaultsIfNotSet()
+            ->prototype('array')
+        ;
         $node->getNode();
     }
 
@@ -149,6 +153,50 @@ public function testNestedPrototypedArrayNodes()
         $node->getNode();
     }
 
+    public function testEnabledNodeDefaults()
+    {
+        $node = new ArrayNodeDefinition('root');
+        $node
+            ->canBeEnabled()
+            ->children()
+                ->scalarNode('foo')->defaultValue('bar')->end()
+        ;
+
+        $this->assertEquals(array('enabled' => false, 'foo' => 'bar'), $node->getNode()->getDefaultValue());
+    }
+
+    /**
+     * @dataProvider getEnableableNodeFixtures
+     */
+    public function testTrueEnableEnabledNode($expected, $config, $message)
+    {
+        $processor = new Processor();
+        $node = new ArrayNodeDefinition('root');
+        $node
+            ->canBeEnabled()
+            ->children()
+                ->scalarNode('foo')->defaultValue('bar')->end()
+        ;
+
+        $this->assertEquals(
+            $expected,
+            $processor->process($node->getNode(), $config),
+            $message
+        );
+    }
+
+    public function getEnableableNodeFixtures()
+    {
+        return array(
+            array(array('enabled' => true, 'foo' => 'bar'), array(true), 'true enables an enableable node'),
+            array(array('enabled' => true, 'foo' => 'bar'), array(null), 'null enables an enableable node'),
+            array(array('enabled' => true, 'foo' => 'bar'), array(array('enabled' => true)), 'An enableable node can be enabled'),
+            array(array('enabled' => true, 'foo' => 'baz'), array(array('foo' => 'baz')), 'any configuration enables an enableable node'),
+            array(array('enabled' => false, 'foo' => 'baz'), array(array('foo' => 'baz', 'enabled' => false)), 'An enableable node can be disabled'),
+            array(array('enabled' => false, 'foo' => 'bar'), array(false), 'false disables an enableable node'),
+        );
+    }
+
     protected function getField($object, $field)
     {
         $reflection = new \ReflectionProperty($object, $field);
diff --git a/src/Symfony/Component/DependencyInjection/CHANGELOG.md b/src/Symfony/Component/DependencyInjection/CHANGELOG.md
index 686bd5656f86..4839bd8bee7b 100644
--- a/src/Symfony/Component/DependencyInjection/CHANGELOG.md
+++ b/src/Symfony/Component/DependencyInjection/CHANGELOG.md
@@ -4,6 +4,7 @@ CHANGELOG
 2.2.0
 -----
 
+ * added Extension::isConfigEnabled() to ease working with enableable configurations
  * added an Extension base class with sensible defaults to be used in conjunction
    with the Config component.
  * added PrependExtensionInterface (to be able to allow extensions to prepend
diff --git a/src/Symfony/Component/DependencyInjection/Extension/Extension.php b/src/Symfony/Component/DependencyInjection/Extension/Extension.php
index e5c51a7b5892..bc1eaa1ffac8 100644
--- a/src/Symfony/Component/DependencyInjection/Extension/Extension.php
+++ b/src/Symfony/Component/DependencyInjection/Extension/Extension.php
@@ -12,6 +12,8 @@
 namespace Symfony\Component\DependencyInjection\Extension;
 
 use Symfony\Component\DependencyInjection\Container;
+use Symfony\Component\DependencyInjection\Exception\BadMethodCallException;
+use Symfony\Component\DependencyInjection\Exception\InvalidArgumentException;
 use Symfony\Component\Config\Resource\FileResource;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\Config\Definition\Processor;
@@ -62,26 +64,19 @@ public function getNamespace()
      *
      * @return string The alias
      *
-     * @throws \BadMethodCallException When the extension name does not follow conventions
+     * @throws BadMethodCallException When the extension name does not follow conventions
      */
     public function getAlias()
     {
         $className = get_class($this);
         if (substr($className, -9) != 'Extension') {
-            throw new \BadMethodCallException('This extension does not follow the naming convention; you must overwrite the getAlias() method.');
+            throw new BadMethodCallException('This extension does not follow the naming convention; you must overwrite the getAlias() method.');
         }
         $classBaseName = substr(strrchr($className, '\\'), 1, -9);
 
         return Container::underscore($classBaseName);
     }
 
-    final protected function processConfiguration(ConfigurationInterface $configuration, array $configs)
-    {
-        $processor = new Processor();
-
-        return $processor->processConfiguration($configuration, $configs);
-    }
-
     /**
      * {@inheritDoc}
      */
@@ -104,4 +99,28 @@ public function getConfiguration(array $config, ContainerBuilder $container)
 
         return null;
     }
+
+    final protected function processConfiguration(ConfigurationInterface $configuration, array $configs)
+    {
+        $processor = new Processor();
+
+        return $processor->processConfiguration($configuration, $configs);
+    }
+
+    /**
+     * @param ContainerBuilder $container
+     * @param array            $config
+     *
+     * @return Boolean Whether the configuration is enabled
+     *
+     * @throws InvalidArgumentException When the config is not enableable
+     */
+    protected function isConfigEnabled(ContainerBuilder $container, array $config)
+    {
+        if (!array_key_exists('enabled', $config)) {
+            throw new InvalidArgumentException("The config array has no 'enabled' key.");
+        }
+
+        return (Boolean) $container->getParameterBag()->resolveValue($config['enabled']);
+    }
 }
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Extension/ExtensionTest.php b/src/Symfony/Component/DependencyInjection/Tests/Extension/ExtensionTest.php
new file mode 100644
index 000000000000..e35bbd5d3c8a
--- /dev/null
+++ b/src/Symfony/Component/DependencyInjection/Tests/Extension/ExtensionTest.php
@@ -0,0 +1,81 @@
+<?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\DependencyInjection\Tests\Extension;
+
+class ExtensionTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @dataProvider getResolvedEnabledFixtures
+     */
+    public function testIsConfigEnabledReturnsTheResolvedValue($enabled)
+    {
+        $pb = $this->getMockBuilder('Symfony\Component\DependencyInjection\ParameterBag\ParameterBag')
+            ->setMethods(array('resolveValue'))
+            ->getMock()
+        ;
+
+        $container = $this->getMockBuilder('Symfony\Component\DependencyInjection\ContainerBuilder')
+            ->setMethods(array('getParameterBag'))
+            ->getMock()
+        ;
+
+        $pb->expects($this->once())
+            ->method('resolveValue')
+            ->with($this->equalTo($enabled))
+            ->will($this->returnValue($enabled))
+        ;
+
+        $container->expects($this->once())
+            ->method('getParameterBag')
+            ->will($this->returnValue($pb))
+        ;
+
+        $extension = $this->getMockBuilder('Symfony\Component\DependencyInjection\Extension\Extension')
+            ->setMethods(array())
+            ->getMockForAbstractClass()
+        ;
+
+        $r = new \ReflectionMethod('Symfony\Component\DependencyInjection\Extension\Extension', 'isConfigEnabled');
+        $r->setAccessible(true);
+
+        $r->invoke($extension, $container, array('enabled' => $enabled));
+    }
+
+    public function getResolvedEnabledFixtures()
+    {
+        return array(
+            array(true),
+            array(false)
+        );
+    }
+
+    /**
+     * @expectedException \Symfony\Component\DependencyInjection\Exception\InvalidArgumentException
+     * @expectedExceptionMessage The config array has no 'enabled' key.
+     */
+    public function testIsConfigEnabledOnNonEnableableConfig()
+    {
+        $container = $this->getMockBuilder('Symfony\Component\DependencyInjection\ContainerBuilder')
+            ->getMock()
+        ;
+
+        $extension = $this->getMockBuilder('Symfony\Component\DependencyInjection\Extension\Extension')
+            ->setMethods(array())
+            ->getMockForAbstractClass()
+        ;
+
+        $r = new \ReflectionMethod('Symfony\Component\DependencyInjection\Extension\Extension', 'isConfigEnabled');
+        $r->setAccessible(true);
+
+        $r->invoke($extension, $container, array());
+    }
+}