This is not an ignorant question. Any half-experienced Erlang developer can tell you that you use `list_to_existing_atom' rather than `list_to_atom' if you are

This is not an ignorant question. Any half-experienced Erlang developer can tell you that you use `list_to_existing_atom' rather than `list_to_atom' if you are ever doing dynamic things with atoms. So, if you're trying to accomplish dynamic module lookup and foo_baz.beam is in your code path, default startup will create the `foo_baz' atom, and you know that this atom will exist at runtime. Symbols in Ruby are atoms (the term "atom" spans languages), and GC/space issues plague any persistent term like an atom, in any language. And thus I arrive at a key question: Does Ruby have something like `list_to_existing_atom', or some mechanism for telling if a symbol exists already? I see no analog to this, only the `ID2SYM' macro in the extensions API, and similar calls like String#to_sym. Perhaps there is some way to clean up symbols after they are created. This to me would seem like the ideal route. It's good they've got a stop-gap fix by changing defaults, but it feels to me like they're punting here. Perhaps users who do [ab]use this feature also would not like DOS attacks? I hope others who know more about Ruby extension development, and symbol management capabilities, can chime in on these questions.