# File lib/sprockets/base.rb, line 255
      def circular_call_protection(path)
        reset = Thread.current[:sprockets_circular_calls].nil?
        calls = Thread.current[:sprockets_circular_calls] ||= Set.new
        if calls.include?(path)
          raise CircularDependencyError, "#{path} has already been required"
        end
        calls << path
        yield
      ensure
        Thread.current[:sprockets_circular_calls] = nil if reset
      end