anchor.diff:      // Resolve the branch.
       if (branch == null) {
         // Default to the latest stable.
  -      branch = null;
  +      branch = 'master';
       } else {
         if (_PACKAGE_BRANCH_SIMPLE_REGEXP.matchAsPrefix(branch) == null) {
           // This is an extended semver version or version range.
           if (SparkFlags.bowerMapComplexVerToLatestStable) {
             resolution = _Resolved.COMPLEX_VERSION_DEFAULTED;
  -          branch = null;
  +          branch = 'master';
           } else {
             // TODO(ussuri): Add full support for semver versions and ranges.
             resolution = _Unresolved.COMPLEX_VERSION;
  
positive.code:   static const STAR_PATH_MAPPED = const _Resolved._(
        '"*" path resolved using mappings from config files');
    static const NORMAL_PATH_OVERRIDDEN = const _Resolved._(
        'regular path overridden using mappings from config files');
    static const COMPLEX_VERSION_DEFAULTED = const _Resolved._(
        'unsupported complex version defaulted to latest stable');
  }
  
  class _Unresolved extends _Resolution {
  
negative.code: 
    Map<String, _Package> _allDeps = {};
  
    final _alteredDepsComments = new Set<String>();
    final _unresolvedDepsComments = new Set<String>();
    final _ignoredDepsComments = new Set<String>();
  
    BowerFetcher(this._packagesDir, this._packageSpecFileName);
  
  