class Bundler::LockfileParser

def warn_for_outdated_bundler_version
  return unless bundler_version
  prerelease_text = bundler_version.prerelease? ? " --pre" : ""
  current_version = Gem::Version.create(Bundler::VERSION)
  case current_version.segments.first <=> bundler_version.segments.first
  when -1
    raise LockfileError, "You must use Bundler #{bundler_version.segments.first} or greater with this lockfile."
  when 0
    if current_version < bundler_version
      Bundler.ui.warn "Warning: the running version of Bundler is older " \
           "than the version that created the lockfile. We suggest you " \
           "upgrade to the latest version of Bundler by running `gem " \
           "install bundler#{prerelease_text}`.\n"
    end
  end
end