ruby

# File lib/rubygems/request_set/gem_dependency_api.rb, line 784
  def ruby version, options = {}
    engine         = options[:engine]
    engine_version = options[:engine_version]

    raise ArgumentError,
          'You must specify engine_version along with the Ruby engine' if
            engine and not engine_version

    return true if @installing

    unless RUBY_VERSION == version then
      message = "Your Ruby version is #{RUBY_VERSION}, " +
                "but your #{gem_deps_file} requires #{version}"

      raise Gem::RubyVersionMismatch, message
    end

    if engine and engine != Gem.ruby_engine then
      message = "Your Ruby engine is #{Gem.ruby_engine}, " +
                "but your #{gem_deps_file} requires #{engine}"

      raise Gem::RubyVersionMismatch, message
    end

    if engine_version then
      my_engine_version = Object.const_get "#{Gem.ruby_engine.upcase}_VERSION"

      if engine_version != my_engine_version then
        message =
          "Your Ruby engine version is #{Gem.ruby_engine} #{my_engine_version}, " +
          "but your #{gem_deps_file} requires #{engine} #{engine_version}"

        raise Gem::RubyVersionMismatch, message
      end
    end

    return true
  end