To provide some data-point. Our monolith runs with https://github.com/Shopify/symbol-fstring, which makes the return value of Symbol#to_s
frozen without any problem. I think we had to fix a single gem to make it work a few years back, that's it.
That said, while we run a lot of code (700+ transitive gems), that's not necessarily fully representative of the code out there.
Also one major difference with chilled string literals is that you can't just set RUBYOPT="--disable-frozen-string-literal"
to continue running older code. I guess you could monkey patch String#to_s
though, and provide that as a gem to make it easy to provide backward compatibility.
All this to say that as a Ruby user, I'd like this change to happen, because Symbol#to_s
is a major source of allocation, and Ruby performance is very GC dependent.
But as a Ruby committer I think we need to be careful about the rate of deprecation and backward compatibility breaks. On one hand it would sound logical to ship such change at the same time as the change for frozen string literals, but on the other hand it makes the jump bigger and may alienate some users. So it's a fine line to walk.
So I'm positive, but with some reservations.