django.utils.timezone.make_naive can underflow for timezones close to datetime.min

[Liam DeVoe]

I'm a contributor over at ​Hypothesis. ​We found that saving (or retrieving?) models with aware DateTimeField values close to datetime.min can error if:

• timezone support is enabled (USE_TZ=True)
• you are using the sqlite database (presumably also any other db backend without tz aware support, if they exist?)

Explicitly:

from datetime import datetime, timezone
from zoneinfo import ZoneInfo
from django.utils.timezone import make_naive

dt = datetime.min.replace(tzinfo=ZoneInfo(key='Africa/Addis_Ababa'))
make_naive(dt, timezone.utc) # OverflowError

where make_naive is called from ​here. I would guess the overflow case for datetime.max is symmetric and similar as well.

I hope you'll forgive the lack of a django reproducer - I live in testing land and don't have a local django environment handy :). Hopefully the cause is clear and reproducible with vanilla django models.