# File lib/bundler/source/rubygems.rb, line 257
      def double_check_for(unmet_dependency_names)
        return unless @allow_remote
        return unless api_fetchers.any?

        unmet_dependency_names = unmet_dependency_names.call
        unless unmet_dependency_names.nil?
          if api_fetchers.size <= 1
            # can't do this when there are multiple fetchers because then we might not fetch from _all_
            # of them
            unmet_dependency_names -= remote_specs.spec_names # avoid re-fetching things we've already gotten
          end
          return if unmet_dependency_names.empty?
        end

        Bundler.ui.debug "Double checking for #{unmet_dependency_names || "all specs (due to the size of the request)"} in #{self}"

        fetch_names(api_fetchers, unmet_dependency_names, specs, false)
      end