Pathname#mkpath

# File tmp/rubies/ruby-4.0.0/pathname_builtin.rb, line 334
def mkpath(mode: nil)
  path = @path == '/' ? @path : @path.chomp('/')

  stack = []
  until File.directory?(path) || File.dirname(path) == path
    stack.push path
    path = File.dirname(path)
  end

  stack.reverse_each do |dir|
    dir = dir == '/' ? dir : dir.chomp('/')
    if mode
      Dir.mkdir dir, mode
      File.chmod mode, dir
    else
      Dir.mkdir dir
    end
  rescue SystemCallError
    raise unless File.directory?(dir)
  end

  self
end