Yeah, that works to suppress the warning. It’s still an unnecessary hoop to jump through though, and I’m not keen on unnecessary side effects, even if they are usually transparent. (F.ex., what if this is a tied scalar?)

It also loses the distinction between undef and an empty string, should that be needed.

Compared to the alternative length behaviour, it does remove the need for checking definedness of the return value if it’s needed in calculations, but you can simply apply your approach to the return value instead then: $len += 0; And that avoids the problem with side effects, as the return value of length is never overloaded.

I hadn’t considered this particular point, but as I said, any way the matter is turned, I cannot find a reason to prefer the currently implemented behaviour.

Makeshifts last the longest.