which_to_update

# File lib/rubygems/commands/update_command.rb, line 267
  def which_to_update(highest_installed_gems, gem_names, system = false)
    result = []

    highest_installed_gems.each do |l_name, l_spec|
      next if not gem_names.empty? and
              gem_names.none? { |name| name == l_spec.name }

      highest_remote_ver = highest_remote_version l_spec

      if system or (l_spec.version < highest_remote_ver)
        result << [l_spec.name, [l_spec.version, highest_remote_ver].max]
      end
    end

    result
  end