depend_on

# File activesupport/lib/active_support/dependencies.rb, line 298
    def depend_on(file_name, swallow_load_errors = false, message = "No such file to load -- %s.rb")
      path = search_for_file(file_name)
      require_or_load(path || file_name)
    rescue LoadError => load_error
      unless swallow_load_errors
        if file_name = load_error.message[/ -- (.*?)(\.rb)?$/, 1]
          raise LoadError.new(message % file_name).copy_blame!(load_error)
        end
        raise
      end
    end