JMSSerializerBundle/Metadata/Driver/PhpDriver.php

<?php

namespace JMS\SerializerBundle\Metadata\Driver;

use JMS\SerializerBundle\Metadata\ClassMetadata;
use Metadata\Driver\AbstractFileDriver;

class PhpDriver extends AbstractFileDriver
{
    protected function loadMetadataFromFile(\ReflectionClass $class, $file)
    {
        $metadata = require $file;

        if (!$metadata instanceof ClassMetadata) {
            throw new \RuntimeException(sprintf('The file %s was expected to return an instance of ClassMetadata, but returned %s.', $file, json_encode($metadata)));
        }
        if ($metadata->name !== $class->getName()) {
            throw new \RuntimeException(sprintf('The file %s was expected to return metadata for class %s, but instead returned metadata for class %s.', $class->getName(), $metadata->name));
        }

        return $metadata;
    }

    protected function getExtension()
    {
        return 'php';
    }
}