Safety of Thread.current[] usage in rails

Question

I keep getting conflicting opinions on the practice of storing information in the Thread.current hash (e.g., the current_user, the current subdomain, etc.). The

Answer 1

The accepted answer is technically accurate, but as pointed out in the answer gently, and in http://m.onkey.org/thread-safety-for-your-rails not so gently:

Don't use thread local storage, Thread.current if you don't absolutely have to

The gem for request_store is another solution (better) but just read the readme there for more reasons to stay away from thread local storage.

There is almost always a better way.