Message 158207 - Python tracker
The point isn’t that time.strptime validates dates but that it uses datetime internally:
julian = datetime_date(year, month, day).toordinal() - \
datetime_date(year, 1, 1).toordinal() + 1
Is it worth to reimplement this functionality? It strikes easier to me to just use a different year if year is undefined and date == Feb 29.