Gem::Ext::CargoBuilder#finalize_directory

# File tmp/rubies/ruby-3.2.0/lib/rubygems/ext/cargo_builder.rb, line 268
def finalize_directory(dest_path, lib_dir, extension_dir)
  require "fileutils"
  require "tempfile"

  ext_path = final_extension_path(dest_path)

  begin
    tmp_dest = Dir.mktmpdir(".gem.", extension_dir)

    # Some versions of `mktmpdir` return absolute paths, which will break make
    # if the paths contain spaces.
    #
    # As such, we convert to a relative path.
    tmp_dest_relative = get_relative_path(tmp_dest.clone, extension_dir)

    full_tmp_dest = File.join(extension_dir, tmp_dest_relative)

    # TODO: remove in RubyGems 4
    if Gem.install_extension_in_lib && lib_dir
      FileUtils.mkdir_p lib_dir
      FileUtils.cp_r ext_path, lib_dir, remove_destination: true
    end

    FileUtils::Entry_.new(full_tmp_dest).traverse do |ent|
      destent = ent.class.new(dest_path, ent.rel)
      destent.exist? || FileUtils.mv(ent.path, destent.path)
    end
  ensure
    FileUtils.rm_rf tmp_dest if tmp_dest
  end
end