#35683: django.utils.timezone.make_naive can underflow for timezones close to
datetime.min
-------------------------------+--------------------------------------
Reporter: tybug | Owner: (none)
Type: Bug | Status: new
Component: Uncategorized | Version: 5.1
Severity: Normal | Resolution:
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Description changed by tybug:
Old description:
> I'm a contributor over at [https://github.com/HypothesisWorks/hypothesis
> Hypothesis].
> [https://github.com/HypothesisWorks/hypothesis/pull/4086#issuecomment-2290742590
> 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
> [https://github.com/django/django/blob/a57596e443ecb67140e1a9fc0f0e87446b2d0174/django/db/backends/sqlite3/operations.py#L269
> here]. I would guess the overflow case for datetime.max is symmetric and
> similar as well.
>
> I have half an expectation that this will be a wontfix, but I figured I'd
> give a heads up here. 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.
New description:
I'm a contributor over at [https://github.com/HypothesisWorks/hypothesis
Hypothesis].
[https://github.com/HypothesisWorks/hypothesis/pull/4086#issuecomment-2290742590
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
[https://github.com/django/django/blob/a57596e443ecb67140e1a9fc0f0e87446b2d0174/django/db/backends/sqlite3/operations.py#L269
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.
--
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Ticket URL: <https://code.djangoproject.com/ticket/35683#comment:1>
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