class Bundler::Dsl

def validate_keys(command, opts, valid_keys)
  invalid_keys = opts.keys - valid_keys
  git_source = opts.keys & @git_sources.keys.map(&:to_s)
  if opts["branch"] && !(opts["git"] || opts["github"] || git_source.any?)
    raise GemfileError, %(The `branch` option for `#{command}` is not allowed. Only gems with a git source can specify a branch)
  end
  return true unless invalid_keys.any?
  message = String.new
  message << "You passed #{invalid_keys.map {|k| ":" + k }.join(", ")} "
  message << if invalid_keys.size > 1
    "as options for #{command}, but they are invalid."
  else
    "as an option for #{command}, but it is invalid."
  end
  message << " Valid options are: #{valid_keys.join(", ")}."
  message << " You may be able to resolve this by upgrading Bundler to the newest version."
  raise InvalidOption, message
end