class ContainerBuilder

class ContainerBuilder extends SymfonyContainerBuilder implements ContainerInterface {
    
    /**
     * {@inheritdoc}
     */
    public function __construct(?ParameterBagInterface $parameterBag = NULL) {
        parent::__construct($parameterBag);
        $this->setResourceTracking(FALSE);
    }
    
    /**
     * Overrides Symfony\Component\DependencyInjection\ContainerBuilder::set().
     *
     * Drupal's container builder can be used at runtime after compilation, so we
     * override Symfony's ContainerBuilder's restriction on setting services in a
     * frozen builder.
     *
     * @todo Restrict this to synthetic services only. Ideally, the upstream
     *   ContainerBuilder class should be fixed to allow setting synthetic
     *   services in a frozen builder.
     */
    public function set($id, $service) : void {
        SymfonyContainer::set($id, $service);
    }
    
    /**
     * {@inheritdoc}
     */
    public function register($id, $class = NULL) : Definition {
        $definition = new Definition($class);
        // As of Symfony 5.2 all services are private by default, but in Drupal
        // services are still public by default.
        $definition->setPublic(TRUE);
        return $this->setDefinition($id, $definition);
    }
    
    /**
     * {@inheritdoc}
     */
    public function setAlias($alias, $id) : Alias {
        $alias = parent::setAlias($alias, $id);
        // As of Symfony 3.4 all aliases are private by default.
        $alias->setPublic(TRUE);
        return $alias;
    }
    
    /**
     * {@inheritdoc}
     */
    public function setParameter($name, $value) : void {
        if (strtolower($name) !== $name) {
            throw new \InvalidArgumentException("Parameter names must be lowercase: {$name}");
        }
        parent::setParameter($name, $value);
    }
    
    /**
     * {@inheritdoc}
     */
    public function __sleep() : array {
        assert(FALSE, 'The container was serialized.');
        return array_keys(get_object_vars($this));
    }

}