Symfony\Component\DependencyInjection\ContainerBuilder::removeAlias PHP Method

    public function removeAlias($alias)
    {
        unset($this->aliasDefinitions[strtolower($alias)]);
    }

 public function loadInternal(array $config, ContainerBuilder $container)
 {
     $loader = new XmlFileLoader($container, new FileLocator(array(__DIR__ . '/../Resources/config/')));
     $loader->load('services.xml');
     // Built-in handlers.
     $container->getDefinition('jms_serializer.datetime_handler')->addArgument($config['handlers']['datetime']['default_format'])->addArgument($config['handlers']['datetime']['default_timezone']);
     // property naming
     $container->getDefinition('jms_serializer.camel_case_naming_strategy')->addArgument($config['property_naming']['separator'])->addArgument($config['property_naming']['lower_case']);
     if ($config['property_naming']['enable_cache']) {
         $container->getDefinition('jms_serializer.cache_naming_strategy')->addArgument(new Reference((string) $container->getAlias('jms_serializer.naming_strategy')));
         $container->setAlias('jms_serializer.naming_strategy', 'jms_serializer.cache_naming_strategy');
     }
     $bundles = $container->getParameter('kernel.bundles');
     // metadata
     if ('none' === $config['metadata']['cache']) {
         $container->removeAlias('jms_serializer.metadata.cache');
     } elseif ('file' === $config['metadata']['cache']) {
         $container->getDefinition('jms_serializer.metadata.cache.file_cache')->replaceArgument(0, $config['metadata']['file_cache']['dir']);
         $dir = $container->getParameterBag()->resolveValue($config['metadata']['file_cache']['dir']);
         if (!file_exists($dir)) {
             if (!($rs = @mkdir($dir, 0777, true))) {
                 throw new RuntimeException(sprintf('Could not create cache directory "%s".', $dir));
             }
         }
     } else {
         $container->setAlias('jms_serializer.metadata.cache', new Alias($config['metadata']['cache'], false));
     }
     if ($config['metadata']['infer_types_from_doctrine_metadata'] && isset($bundles['DoctrineBundle'])) {
         $container->setAlias('jms_serializer.metadata_driver', 'jms_serializer.metadata.doctrine_type_driver');
     }
     $container->getDefinition('jms_serializer.metadata_factory')->replaceArgument(2, $config['metadata']['debug']);
     // directories
     $directories = array();
     if ($config['metadata']['auto_detection']) {
         foreach ($bundles as $name => $class) {
             $ref = new \ReflectionClass($class);
             $directories[$ref->getNamespaceName()] = dirname($ref->getFileName()) . '/Resources/config/serializer';
         }
     }
     foreach ($config['metadata']['directories'] as $directory) {
         $directory['path'] = rtrim(str_replace('\\', '/', $directory['path']), '/');
         if ('@' === $directory['path'][0]) {
             $bundleName = substr($directory['path'], 1, strpos($directory['path'], '/') - 1);
             if (!isset($bundles[$bundleName])) {
                 throw new RuntimeException(sprintf('The bundle "%s" has not been registered with AppKernel. Available bundles: %s', $bundleName, implode(', ', array_keys($bundles))));
             }
             $ref = new \ReflectionClass($bundles[$bundleName]);
             $directory['path'] = dirname($ref->getFileName()) . substr($directory['path'], strlen('@' . $bundleName));
         }
         $directories[rtrim($directory['namespace_prefix'], '\\')] = rtrim($directory['path'], '\\/');
     }
     $container->getDefinition('jms_serializer.metadata.file_locator')->replaceArgument(0, $directories);
     $container->setParameter('jms_serializer.xml_deserialization_visitor.doctype_whitelist', $config['visitors']['xml']['doctype_whitelist']);
     $container->setParameter('jms_serializer.json_serialization_visitor.options', $config['visitors']['json']['options']);
     if (!$config['enable_short_alias']) {
         $container->removeAlias('serializer');
     }
 }