class Bundler::RubyVersion

def self.system
  ruby_engine = if defined?(RUBY_ENGINE) && !RUBY_ENGINE.nil?
    RUBY_ENGINE.dup
  else
    # not defined in ruby 1.8.7
    "ruby"
  end
  # :sob: mocking RUBY_VERSION breaks stuff on 1.8.7
  ruby_version = ENV.fetch("BUNDLER_SPEC_RUBY_VERSION") { RUBY_VERSION }.dup
  ruby_engine_version = case ruby_engine
                        when "ruby"
                          ruby_version
                        when "rbx"
                          Rubinius::VERSION.dup
                        when "jruby"
                          JRUBY_VERSION.dup
                        else
                          raise BundlerError, "RUBY_ENGINE value #{RUBY_ENGINE} is not recognized"
  end
  patchlevel = RUBY_PATCHLEVEL.to_s
  @ruby_version ||= RubyVersion.new(ruby_version, patchlevel, ruby_engine, ruby_engine_version)
end