Gem::Util.traverse_parents

# File tmp/rubies/ruby-3.0.5/lib/rubygems/util.rb, line 82
def self.traverse_parents(directory, &block)
  return enum_for __method__, directory unless block_given?

  here = File.expand_path directory
  loop do
    Dir.chdir here, &block rescue Errno::EACCES

    new_here = File.expand_path('..', here)
    return if new_here == here # toplevel
    here = new_here
  end
end