Gem.register_default_spec

# File tmp/rubies/ruby-4.1.0-preview1/lib/rubygems.rb, line 1312
def register_default_spec(spec)
  extended_require_paths = spec.require_paths.map {|f| f + "/" }
  new_format = extended_require_paths.any? {|path| spec.files.any? {|f| f.start_with? path } }

  if new_format
    prefix_group = extended_require_paths.join("|")
    prefix_pattern = /^(#{prefix_group})/
  end

  native_extension_suffixes = Gem.dynamic_library_suffixes.reject(&:empty?)

  spec.files.each do |file|
    if new_format
      file = file.sub(prefix_pattern, "")
      unless $~
        # Also register native extension files (e.g. date_core.bundle)
        # that are listed without require path prefix in the gemspec
        next if file.include?("/")
        next unless file.end_with?(*native_extension_suffixes)
      end
    end

    # RubyGems owns this namespace. Bundler lists copies of some of these
    # files, and mapping them here would make requiring RubyGems' own file
    # activate the default Bundler.
    next if file.start_with?("rubygems/")

    spec.activate if already_loaded?(file)

    @path_to_default_spec_map[file] = spec
    @path_to_default_spec_map[file.sub(suffix_regexp, "")] = spec
  end
end