Symfony\Component\DependencyInjection\Loader\YamlFileLoader::validate PHP Method

    private function validate($content, $file)
    {
        if (null === $content) {
            return $content;
        }

        if (!is_array($content)) {
            throw new InvalidArgumentException(sprintf('The service file "%s" is not valid. It should contain an array. Check your YAML syntax.', $file));
        }

        foreach ($content as $namespace => $data) {
            if (in_array($namespace, array('imports', 'parameters', 'services'))) {
                continue;
            }

            if (!$this->container->hasExtension($namespace)) {
                $extensionNamespaces = array_filter(array_map(function ($ext) { return $ext->getAlias(); }, $this->container->getExtensions()));
                throw new InvalidArgumentException(sprintf(
                    'There is no extension able to load the configuration for "%s" (in %s). Looked for namespace "%s", found %s',
                    $namespace,
                    $file,
                    $namespace,
                    $extensionNamespaces ? sprintf('"%s"', implode('", "', $extensionNamespaces)) : 'none'
                ));
            }
        }

        return $content;
    }