Django timezone same day diff is not 0

Question

test function

from django.utils import timezone

def date_diff_now(date):
    print(date)
    print(timezone.now())
    print(date - timezone.now())
    print((date - timezone.now()).days)

Result

2018-02-07 17:46:36.442314+00:00
2018-02-07 17:47:32.084900+00:00
-1 day, 23:59:04.357374
-1

Why the difference between 2 datetime on the same day does not return 0 ?

What happens if you subtract the smaller from the larger? (ie: timezone.now() - date) — mcalex, Feb 07 '18 at 18:30

score 0 · Accepted Answer · answered Feb 07 '18 at 18:36

From Basic time and dates

If the normalized value of days lies outside the indicated range, OverflowError is raised.

Note that normalization of negative values may be surprising at first. For example,

>>> from datetime import timedelta
>>> d = timedelta(microseconds=-1)
>>> (d.days, d.seconds, d.microseconds)
(-1, 86399, 999999)

So it looks like a known overflow error.

Django timezone same day diff is not 0

1 Answers1