Time Zone warning when filtering on the "past 7 days"

[ukrutt]

When requesting data that's filtered on a "Date range" of "last week", I get a warning in the Django console:

.../.venv/lib/python3.6/site-packages/django/db/models/fields/__init__.py:1393:
RuntimeWarning: DateTimeField Asset.date_added received a naive datetime
(2018-02-08 00:00:00) while time zone support is active.

The reason is that the _truncate function removes time zone info. I am about to open a Pull Request with code that fixes this.

[carltongibson]

Hi @ukrutt. Thanks for the report.

Currently DateRangeFilter only really works with DateFields. _truncate is meant to return a date. When that gets converted to a datetime you're not going to have tzinfo.

Your change in #874 has _truncate return a datetime, which is leading to the failure in the filtering for the object create today in the week filtering test. (Exactly why that's not giving the right result would be interesting: what's the zero-hour datetime getting converted back to a date as? — but I haven't had a chance to look at that.)

There shouldn't be any reason this should work both ways. (Django's ChangeList manages it I think.) So I'd be very happy to look a PR solving the issues here.

[carltongibson]

DateRangeFilter was reworked in #852. Happy to review if still an issue (perhaps with a test case demonstrating). But closing otherwise