class Bundler::Definition

def validate_ruby!
  return unless ruby_version
  if diff = ruby_version.diff(Bundler::RubyVersion.system)
    problem, expected, actual = diff
    msg = case problem
          when :engine
            "Your Ruby engine is #{actual}, but your Gemfile specified #{expected}"
          when :version
            "Your Ruby version is #{actual}, but your Gemfile specified #{expected}"
          when :engine_version
            "Your #{Bundler::RubyVersion.system.engine} version is #{actual}, but your Gemfile specified #{ruby_version.engine} #{expected}"
          when :patchlevel
            if !expected.is_a?(String)
              "The Ruby patchlevel in your Gemfile must be a string"
            else
              "Your Ruby patchlevel is #{actual}, but your Gemfile specified #{expected}"
            end
    end
    raise RubyVersionMismatch, msg
  end
end