為什麼 ruby constant 要 freeze https://waynechu.cc/posts/146-ruby-constant-freeze every where 不論 rack / rails 都會這樣做 https://stackoverflow.com/questions/27702540/why-are-there-frozen-constants-everywhere https://www.honeybadger.io/blog/when-to-use-freeze-and-frozen-in-ruby/ https://ruby-china.org/topics/……