anchor.diff:  
   Future<ExitResult> checkPackage(
       Logger logger, String packageName, bool performDryRun) async {
  -  logger.stdout('Checking package $packageName...');
  -
     String jsonData =
         await _uriDownload('https://pub.dartlang.org/api/packages/$packageName/');
     Map json = jsonDecode(jsonData);
  
positive.code:     return new ExitResult(1, 'No homepage definied for package $packageName.');
    }
  
    if (!homepage.startsWith('https://github.com/')) {
      return new ExitResult(
          1, "Homepage is '$homepage', but we require it to be a github repo.");
    }
  
    String fragment = homepage.substring('https://github.com/'.length);
    if (fragment.endsWith('/')) {
      fragment = fragment.substring(0, fragment.length - 1);
    }
  
    if (fragment.split('/').length > 2) {
      return new ExitResult(
          1,
          'Unsupported homepage reference: $homepage.\n'
  
negative.code:   return await dartFixInternal(logger, [dir], performDryRun);
  }
  
  Future gitClone(Uri uri, Directory dir) async {
    Process process = await Process.start('git', ['clone', uri.toString(), '.'],
        workingDirectory: dir.path);
    return process.exitCode;
  }
  