Restoring YAML fixtures with DateTimeField causes timezone warnings

[aigarius@…]

Loading a YAML fixture with a timezone aware DateTimeField in Django 1.4 will cause the following warning even if the field is defined with timezone information in the YAML file

django/db/models/fields/__init__.py:808: RuntimeWarning: DateTimeField received a naive datetime (2012-08-27 13:01:56.784734) while time zone support is active.

Excerpt from testdata.yaml

[...] , insert_date: !!timestamp '2012-08-27 13:01:56.784734+00:00', [...]

The test data is loaded by adding "fixtures = testdata" at the start of a test case class.

This bug is mentioned in Django test suite - django/trunk/tests/modeltests/timezones/tests.py:SerializationTests

Note: the trick of "MyTests = override_settings(USE_TZ=False)(MyTests)" (from #17940) often does not work as expected, because you can then get "ValueError: SQLite backend does not support timezone-aware datetimes when USE_TZ is False" during fixture loading

[Aymeric Augustin]

Indeed, this is ​a bug in PyYAML, as ​described in this comment.

There hasn't been any activity whatsoever on PyYAML's tracker, besides the creation of new tickets, since over one year. The project looks abandoned.

We aren't going to removing support for YAML fixtures now just because of this bug in PyYAML. We can document this as a known problem ​here and tell people to use JSON fixtures.

Other ideas?

[Russell Keith-Magee]

Historically, we haven't modified Django's docs to point out problems in downstream libraries -- the reasoning being that if the bug is fixed, there's never an action to correct Django's documentation and remove the warning. We've usually relied on the ticket tracker making it easy to find such problems.