traverse_parents

# File lib/rubygems/util.rb, line 112
  def self.traverse_parents directory
    return enum_for __method__, directory unless block_given?

    here = File.expand_path directory
    start = here

    Dir.chdir start

    begin
      loop do
        yield here

        Dir.chdir '..'

        return if Dir.pwd == here # toplevel

        here = Dir.pwd
      end
    ensure
      Dir.chdir start
    end
  end