# File lib/bundler/source/rubygems.rb, line 385
      def remote_specs
        @remote_specs ||= Index.build do |idx|
          index_fetchers = fetchers - api_fetchers

          # gather lists from non-api sites
          fetch_names(index_fetchers, nil, idx, false)

          # because ensuring we have all the gems we need involves downloading
          # the gemspecs of those gems, if the non-api sites contain more than
          # about 500 gems, we treat all sites as non-api for speed.
          allow_api = idx.size < API_REQUEST_LIMIT && dependency_names.size < API_REQUEST_LIMIT
          Bundler.ui.debug "Need to query more than #{API_REQUEST_LIMIT} gems." \
            " Downloading full index instead..." unless allow_api

          fetch_names(api_fetchers, allow_api && dependency_names, idx, false)
        end
      end