F() Expressions updating dates in .update() field fails on SQLite

[Gary Graham]

Upon upgrading from 1.8 -> 1.10, I noticed that some code I had written now threw an error. Specifically, attempting to update datetime field's via F expression.

Branch with test showing regression -> ​https://github.com/tadgh/django/commit/c31133261c68b10525b8e3b34e6895a0c6ece4d0

Bisected to ed83881e648771d22658f21b939f66e75c499864: Fixed #23820 -- Supported per-database time zone.

Stacktrace from failure:

======================================================================
ERROR: test_F_expression_fails (timezones.test_regression.ProveRegression)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/tadgh/Projects/django/tests/timezones/test_regression.py", line 22, in test_F_expression_fails
    self.timestamp.refresh_from_db()
  File "/home/tadgh/Projects/django/django/db/models/base.py", line 585, in refresh_from_db
    db_instance = db_instance_qs.get()
  File "/home/tadgh/Projects/django/django/db/models/query.py", line 381, in get
    num = len(clone)
  File "/home/tadgh/Projects/django/django/db/models/query.py", line 240, in __len__
    self._fetch_all()
  File "/home/tadgh/Projects/django/django/db/models/query.py", line 1061, in _fetch_all
    self._result_cache = list(self.iterator())
  File "/home/tadgh/Projects/django/django/db/models/query.py", line 68, in __iter__
    for row in compiler.results_iter(results):
  File "/home/tadgh/Projects/django/django/db/models/sql/compiler.py", line 806, in results_iter
    row = self.apply_converters(row, converters)
  File "/home/tadgh/Projects/django/django/db/models/sql/compiler.py", line 790, in apply_converters
    value = converter(value, expression, self.connection, self.query.context)
  File "/home/tadgh/Projects/django/django/db/backends/sqlite3/operations.py", line 159, in convert_datetimefield_value
    value = timezone.make_aware(value, self.connection.timezone)
  File "/home/tadgh/Projects/django/django/utils/timezone.py", line 364, in make_aware
    return timezone.localize(value, is_dst=is_dst)
  File "/home/tadgh/.venvs/django_env/lib/python3.4/site-packages/pytz/__init__.py", line 227, in localize
    raise ValueError('Not naive datetime (tzinfo is already set)')
ValueError: Not naive datetime (tzinfo is already set)

[Tim Graham]

The regression seems limited to SQLite. If you could provide a patch, we can backport to 1.10. Thanks.

[Gary Graham]

Replying to Tim Graham:

The regression seems limited to SQLite. If you could provide a patch, we can backport to 1.10. Thanks.

OK, but I have no clue where to even start looking. I will start tracing, but if you could give me a reasonable starting point, I would appreciate it. The first time I ever opened the Django repo was to submit this bug.

[Tim Graham]

In the sqlite3/operations.py file referenced in the traceback, it might be enough to check the datetime using django.utils.timezone.is_aware() and skip the timezone.make_aware() call if appropriate.

[Andrew Nester]

I added pull request for this issue ​PR

[Tim Graham <timograham@…>]

In ade52ef7:

Fixed #27544 -- Fixed QuerySet.update(dt=F('dt') + timedelta) crash on SQLite.

[Tim Graham <timograham@…>]

In 75de55f1:

[1.10.x] Fixed #27544 -- Fixed QuerySet.update(dt=F('dt') + timedelta) crash on SQLite.

Backport of ade52ef71f04e57e217585358cb289098260e3ec from master

[Florian Klink]

I also got hit by this one. I backported the commit to the stable/1.9.x branch, you can find my ​PR here.

Replying to Tim Graham <timograham@…>:

In 75de55f1:

[1.10.x] Fixed #27544 -- Fixed QuerySet.update(dt=F('dt') + timedelta) crash on SQLite.

Backport of ade52ef71f04e57e217585358cb289098260e3ec from master

[Florian Klink]

The ​PR got rejected:

As per our supported versions policy, 1.9 only receives security support now (and will be unsupported in April upon the release of Django 1.11).

So I close this here again.