lockfile_version

# File lib/rubygems/bundler_version_finder.rb, line 64
  def self.lockfile_version
    return unless lockfile = lockfile_contents
    lockfile, contents = lockfile
    lockfile ||= "lockfile"
    regexp = /\n\nBUNDLED WITH\n\s{2,}(#{Gem::Version::VERSION_PATTERN})\n/
    return unless contents =~ regexp
    [$1, lockfile]
  end