public function writeComposerJson($contents) {
    // Ensure that require and require-dev are objects and not arrays.
    if (array_key_exists('require', $contents) && is_array($contents['require'])) {
      ksort($contents['require']);
      $contents['require'] = (object) $contents['require'];
    }
    if (array_key_exists('require-dev', $contents)&& is_array($contents['require-dev'])) {
      ksort($contents['require-dev']);
      $contents['require-dev'] = (object) $contents['require-dev'];
    }
    file_put_contents($this->composerJsonFilepath, json_encode($contents, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES));
  }