anchor.diff:          assert(value != null);
           libs = value;
   
  -        return _getCommitMessageFuture(gitDir);
  +        return _getCommitMessageFuture(gitDir, isClean);
         })
         .then((String commitMessage) {
   
  
positive.code: 
    GitDir gitDir;
    List<String> libs;
  
    return GitDir.fromExisting(currentWorkingDir)
        .then((GitDir value) {
  
negative.code: 
          return gitDir.isWorkingTreeClean();
        })
        .then((bool value) {
          isClean = value;
          if(!allowDirty && !isClean) {
            ctx.fail('Working tree is dirty. Cannot generate docs.');
          }
  