find_rakefile_location

# File lib/rake/application.rb, line 657
    def find_rakefile_location # :nodoc:
      here = Dir.pwd
      until (fn = have_rakefile)
        Dir.chdir("..")
        return nil if Dir.pwd == here || options.nosearch
        here = Dir.pwd
      end
      [fn, here]
    ensure
      Dir.chdir(Rake.original_dir)
    end