anchor.diff:  
   /// Returns the name of the git command-line app, or `null` if Git could not be
   /// found on the user's PATH.
  -String get command {
  +String? get command {
     if (_commandCache != null) return _commandCache;
   
     if (_tryGitCommand('git')) {
  
positive.code: 
    log.muteProgress();
    try {
      var result = await runProcess(command, args,
          workingDir: workingDir,
          environment: {...?environment, 'LANG': 'en_GB'});
      if (!result.success) {
  
negative.code: 
  /// Like [run], but synchronous.
  List<String> runSync(List<String> args,
      {String? workingDir, Map<String, String>? environment}) {
    if (!isInstalled) {
      fail('Cannot find a Git executable.\n'
          'Please ensure Git is correctly installed.');
    }
  
    final result = runProcessSync(command!, args,
        workingDir: workingDir, environment: environment);
    if (!result.success) {
      throw GitException(args, result.stdout.join('\n'), result.stderr.join('\n'),
  