What people seem to be missing here is that enums are just a reflection of functionality. If you make your enum non exhaustive then add a field, and something stops working because it's now missing critical messages, it's still a breaking change!
It's always up to callers to decide to handle everything, or decide that additions are non-fatal and use a wildcard branch to ignore them. The same enum could need to be exhaustive for one use case, or subset matched by another.
It's always up to callers to decide to handle everything, or decide that additions are non-fatal and use a wildcard branch to ignore them. The same enum could need to be exhaustive for one use case, or subset matched by another.