anchor.diff:      final args = withFlutter
           ? ['packages', 'pub', 'list-package-dirs']
           : ['list-package-dirs'];
  +
  +    _print(['list-package-dirs:', proc, ...args].join(' '));
  +    _print('  in path `$path`');
   
       final result = Process.runSync(
         proc,
  
positive.code:       return null;
      }
  
      final json = jsonDecode(response.body);
  
      assert(json['name'] == packageName);
  
      final versions = (json['versions'] as List)
          .map((str) => Version.parse(str as String))
          .toList();
  
      final primary = primaryVersion(versions, includePreRelease);
  
      return primary;
    }
  }
  
  
negative.code:     assert(Directory(directory).existsSync());
  
      final pubspecPath = p.join(directory, 'pubspec.yaml');
  
      _print('open pubspec: $pubspecPath');
  
      return Pubspec.parse(
        File(pubspecPath).readAsStringSync(),
  