Warning when creating a Source with default due_poll value

[philgyford]

If I have USE_TZ = True in my settings, and I create a new Source without setting its due_poll field:

source = Source.objects.create(feed_url="https://example.com/feed")

Then I get this warning:

/usr/local/lib/python3.10/site-packages/django/db/models/fields/__init__.py:1564: RuntimeWarning: DateTimeField Source.due_poll received a naive datetime (1900-01-01 00:00:00) while time zone support is active.
  warnings.warn(

Because the default value is set like this:

    due_poll      = models.DateTimeField(default=datetime.datetime(1900, 1, 1))

I'm not sure off the top of my head the best way to fix this, taking into account the value of USE_TZ and which version of Django is currently used, given the change from pytz to zoneinfo (available in python from 3.9) that happened with Django 4.0. e.g. https://stackoverflow.com/a/71823301/250962

And, fwiw, timezone support will be enabled by default with Django 5.0.

[philgyford]

I tried doing this to add a timezone:

from django.utils.timezone import make_aware

    due_poll      = models.DateTimeField(default=make_aware(datetime.datetime(1900, 1, 1)))

In the resulting migration it comes out as :

        migrations.AlterField(
            model_name='source',
            name='due_poll',
            field=models.DateTimeField(
                default=datetime.datetime(1900, 1, 1, 5, 0, tzinfo=datetime.timezone.utc)
            ),
        ),

The odd thing is, it sets the timezone to UTC regardless of whether my project has USE_TZ set to True or False, and even if I have USE_TZ = True and TIME_ZONE = 'America/New_York'.

Maybe that's fine? I'm not sure. I guess, given it's over a century ago, it's not that important which timezone it's in :)

Happy to add a pull request for this too - let me know.

[xurble]

There's a way to do this using a callable generator as the default value. I'll dig it out from another project I've used it on.

[xurble]

Although, actually your way is just fine too 🤷‍♂️