anchor.diff:        contents = deleteMapKey(_contents, _yamlMap, key);
       }
     }
  +
     VersionConstraint get sdkConstraint {
       var env = _yamlMap['environment'];
       if (env == null) return VersionConstraint.any;
  
positive.code:     }
      return _versionConstraints;
    }
    Map<String, VersionConstraint> _versionConstraints;
  
    Pubspec(
  
negative.code:       contents = setMapKey(_contents, env, 'sdk', "'$constraint'", false);
      }
    }
  
    Map<String, dynamic> get dependencies =>
        _yamlMap.containsKey('dependencies') ?
            _yamlMap['dependencies'] : const {};
  
    Map<String, dynamic> get devDependencies =>
        _yamlMap.containsKey('dev_dependencies') ?
            _yamlMap['dev_dependencies'] : const {};
  
    Map<String, dynamic> get dependencyOverrides =>
        _yamlMap.containsKey('dependency_overrides') ?
            _yamlMap['dependency_overrides'] : const {};
  
    List<String> get immediateDependencyNames => []
        ..addAll(dependencies.keys)
        ..addAll(devDependencies.keys);
  