anchor.diff:                  // We output data that matches the format that
                   // PubspecDependency.parse can handle. The data.suffix is any
                   // previously-specified trailing comment.
  +                assert(versions.contains(data.name));
                   output.add('  ${data.name}: ${versions.versionFor(data.name)}${data.suffix}');
                 } else {
                   // If it wasn't a regular dependency, then we output the line
  
positive.code:   result.writeln('dependencies:');
    overrides.writeln('dependency_overrides:');
    for (PubspecDependency dependency in dependencies)
      dependency.describeForFakePubspec(result, overrides);
    result.write(overrides.toString());
    return result.toString();
  }
  
negative.code:   /// excluding any listen in `seen`.
    Iterable<String> getTransitiveDependenciesFor(String package, { Set<String> seen }) sync* {
      seen ??= new Set<String>();
      if (!_dependencyTree.containsKey(package)) {
        // We have no transitive dependencies extracted for flutter_sdk packages
        // because they were omitted from pubspec.yaml used for 'pub upgrade' run.
        return;
      }
      for (String dependency in _dependencyTree[package]) {
        if (!seen.contains(dependency)) {
          yield dependency;
  