FileUtils.cp_r using preserve fails if there are symlinks

gistfile1.rb

# FileUtils.cp_r using "preserve: true" fails if there's a symlink that points to a file that has not yet
# been copied over.  This is because "preserve" updates the metadata for the files (including symlink files)
# and the symlink will not be valid when it is saved (causing a failure).

require "fileutils"

base = "./fileutils_cp_r_base"
dest = "./fileutils_cp_r_dest"

{ "A" => "B", "B" => "A" }.each do |symlink, file|
  puts "Testing FileUtils.cp_r(preserve: true) with a symlink from #{symlink} pointing to a real file #{file}"

  `mkdir #{base}`
  `touch #{base}/#{file}`
  `ln -s #{base}/#{file} #{base}/#{symlink}`

  begin
    FileUtils.cp_r(base, dest, preserve: true)
    puts "We never get here.\n"
  rescue Errno::ENOENT => e
    puts "ERROR: #{e.to_s}\n"
  ensure
    `rm -rf #{base}`
    `rm -rf #{dest}`
  end
end