Issue #2926771: PHP notice when destination file doesn't have an extension

    // name. Preserves the mime type in different stream wrapper

    // implementations.

    $parts = pathinfo($destination);

    $extension = '.' . $parts['extension'];

    $extension = isset($parts['extension']) ? '.' . $parts['extension'] : '';

    if ($extension === '.gz') {

      $parts = pathinfo($parts['filename']);

      $extension = '.' . $parts['extension'] . $extension;