Fixed #17808 -- Explained why fixtures can trigger RuntimeWarnings after enabling time zone support, and how to fix them.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17637 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Aymeric Augustin 2012-03-03 10:13:35 +00:00
parent c0e73a4909
commit 3576c99f74
1 changed files with 32 additions and 5 deletions

View File

@ -380,8 +380,8 @@ Migration guide
Here's how to migrate a project that was started before Django supported time
zones.
Data
----
Database
--------
PostgreSQL
~~~~~~~~~~
@ -428,15 +428,42 @@ code: :func:`~django.utils.timezone.now`,
:func:`~django.utils.timezone.make_naive`.
Finally, in order to help you locate code that needs upgrading, Django raises
a warning when you attempt to save a naive datetime to the database. During
development, you can turn such warnings into exceptions and get a traceback
by adding the following to your settings file::
a warning when you attempt to save a naive datetime to the database::
RuntimeWarning: DateTimeField received a naive datetime (2012-01-01 00:00:00) while time zone support is active.
During development, you can turn such warnings into exceptions and get a
traceback by adding the following to your settings file::
import warnings
warnings.filterwarnings(
'error', r"DateTimeField received a naive datetime",
RuntimeWarning, r'django\.db\.models\.fields')
Fixtures
--------
When serializing an aware datetime, the UTC offset is included, like this::
"2011-09-01T13:20:30+03:00"
For a naive datetime, it obviously isn't::
"2011-09-01T13:20:30"
For models with :class:`~django.db.models.DateTimeField`\ s, this difference
makes it impossible to write a fixture that works both with and without time
zone support.
Fixtures generated with ``USE_TZ = False``, or before Django 1.4, use the
"naive" format. If your project contains such fixtures, after you enable time
zone support, you'll see :exc:`RuntimeWarning`\ s when you load them. To get
rid of the warnings, you must convert your fixtures to the "aware" format.
You can regenerate fixtures with :djadmin:`loaddata` then :djadmin:`dumpdata`.
Or, if they're small enough, you can simply edit them to add the UTC offset
that matches your :setting:`TIME_ZONE` to each serialized datetime.
.. _pytz: http://pytz.sourceforge.net/
.. _these issues: http://pytz.sourceforge.net/#problems-with-localtime
.. _tz database: http://en.wikipedia.org/wiki/Tz_database