This seems substantially less likely to be a problem since (a) G-V-u is relatively rare compared to Y-m-d (b) The choice-of-year problem is inherent to week-ba

This seems substantially less likely to be a problem since (a) G-V-u is relatively rare compared to Y-m-d (b) The choice-of-year problem is inherent to week-based dates, but not to month-based dates, since years are not week-aligned, so knowing the difference is table stakes for implementors of week-based timestamps Now, "isoyear" seems like an awful name in various ways, not least of which is people seeing "iso" and assuming that this is what they really want (i.e. the same problem all over again)...