# File lib/bundler/source.rb, line 325
      def install(spec)
        Bundler.ui.debug "  * Using git #{uri}"

        if @installed
          Bundler.ui.debug "  * Already checked out revision: #{ref}"
        else
          Bundler.ui.debug "  * Checking out revision: #{ref}"
          checkout
          @installed = true
        end
        generate_bin(spec)
      end