class Bundler::RubyVersion

def diff(other)
  if engine != other.engine && @input_engine
    [ :engine, engine, other.engine ]
  elsif version != other.version
    [ :version, version, other.version ]
  elsif engine_version != other.engine_version && @input_engine
    [ :engine_version, engine_version, other.engine_version ]
  elsif patchlevel != other.patchlevel && @patchlevel
    [ :patchlevel, patchlevel, other.patchlevel ]
  else
    nil
  end
end