Merge branch '2.8' into 3.0

* 2.8:
  fixed test
  [Request] Ignore invalid IP addresses sent by proxies
  [EventDispatcher] TraceableEventDispatcher resets listener priorities
  Throw for missing container extensions
  [TwigBridge] add missing unit tests (AppVariable)
  Able to load big xml files with DomCrawler
  fixed typo
  [Form] Fix constraints could be null if not set
  [Finder] Check PHP version before applying a workaround for a PHP bug
  fixed CS
  add defaultNull to version
  sort bundles in config:dump-reference command
  Fixer findings.
  Profiler CSS position conflicts with JS detection
  [Translation][Writer] avoid calling setBackup if the dumper is not an instance of FileDumper.
  [FrameworkBundle] Compute the kernel root hash only one time

Author: fabpot

Command/AbstractConfigCommand.php

@@ -54,6 +54,10 @@ protected function findExtension($name)
         $bundles = $this->initializeBundles();
         foreach ($bundles as $bundle) {
             if ($name === $bundle->getName()) {
+                if (!$bundle->getContainerExtension()) {
+                    throw new \LogicException(sprintf('Bundle "%s" does not have a container extension.', $name));
+                }
+
                 return $bundle->getContainerExtension();
             }
 

DependencyInjection/Configuration.php

@@ -392,6 +392,7 @@ private function addAssetsSection(ArrayNodeDefinition $rootNode)
                                 ->fixXmlConfig('base_url')
                                 ->children()
                                     ->scalarNode('version')
+                                        ->defaultNull()
                                         ->beforeNormalization()
                                         ->ifTrue(function ($v) { return '' === $v; })
                                         ->then(function ($v) { return; })

DependencyInjection/FrameworkExtension.php

@@ -38,6 +38,11 @@ class FrameworkExtension extends Extension
     private $translationConfigEnabled = false;
     private $sessionConfigEnabled = false;
 
+    /**
+     * @var string|null
+     */
+    private $kernelRootHash;
+
     /**
      * Responds to the app.config configuration parameter.
      *
@@ -767,7 +772,7 @@ private function registerValidationConfiguration(array $config, ContainerBuilder
         if (isset($config['cache'])) {
             $container->setParameter(
                 'validator.mapping.cache.prefix',
-                'validator_'.hash('sha256', $container->getParameter('kernel.root_dir'))
+                'validator_'.$this->getKernelRootHash($container)
             );
 
             $validatorBuilder->addMethodCall('setMetadataCache', array(new Reference($config['cache'])));
@@ -943,7 +948,7 @@ private function registerSerializerConfiguration(array $config, ContainerBuilder
         if (isset($config['cache']) && $config['cache']) {
             $container->setParameter(
                 'serializer.mapping.cache.prefix',
-                'serializer_'.hash('sha256', $container->getParameter('kernel.root_dir'))
+                'serializer_'.$this->getKernelRootHash($container)
             );
 
             $container->getDefinition('serializer.mapping.class_metadata_factory')->replaceArgument(
@@ -978,6 +983,22 @@ private function registerPropertyInfoConfiguration(array $config, ContainerBuild
         }
     }
 
+    /**
+     * Gets a hash of the kernel root directory.
+     *
+     * @param ContainerBuilder $container
+     *
+     * @return string
+     */
+    private function getKernelRootHash(ContainerBuilder $container)
+    {
+        if (!$this->kernelRootHash) {
+            $this->kernelRootHash = hash('sha256', $container->getParameter('kernel.root_dir'));
+        }
+
+        return $this->kernelRootHash;
+    }
+
     /**
      * Returns the base path for the XSD files.
      *