class Git::Lib

def revparse(string) 

def revparse(string)
  return string if string =~ /[A-Fa-f0-9]{40}/  # passing in a sha - just no-op it
  rev = ['head', 'remotes', 'tags'].map do |d|
    File.join(@git_dir, 'refs', d, string)
  end.find do |path|
    File.file?(path)
  end
  return File.read(rev).chomp if rev
  command('rev-parse', string)
end