forms.DateTimeField parses ISO 8601 datetime with offset as aware when USE_TZ is False.

[Carlton Gibson]

The following test fails on 3.1a1.

USE_TZ: If this is set to True, Django will use timezone-aware datetimes internally. Otherwise, Django will use naive datetimes in local time.

diff --git a/tests/forms_tests/field_tests/test_datetimefield.py b/tests/forms_tests/field_tests/test_datetimefield.py
index f0e6ada3c5..ed035497d8 100644
--- a/tests/forms_tests/field_tests/test_datetimefield.py
+++ b/tests/forms_tests/field_tests/test_datetimefield.py
@@ -2,8 +2,8 @@ from datetime import date, datetime
 
 from django.core.exceptions import ValidationError
 from django.forms import DateTimeField
-from django.test import SimpleTestCase
-from django.utils.timezone import get_fixed_timezone, utc
+from django.test import SimpleTestCase, override_settings
+from django.utils.timezone import get_fixed_timezone, is_naive, utc
 
 
 class DateTimeFieldTest(SimpleTestCase):
@@ -65,6 +65,12 @@ class DateTimeFieldTest(SimpleTestCase):
             with self.subTest(value=value):
                 self.assertEqual(f.clean(value), expected_datetime)
 
+    @override_settings(USE_TZ=False)
+    def test_use_tz_false(self):
+        f = DateTimeField()
+        value = '2014-09-23T22:34Z'
+        self.assertTrue(is_naive(f.clean(value)))
+
     def test_datetimefield_clean_invalid(self):
         f = DateTimeField()
         msg = "'Enter a valid date/time.'"

Expected behaviour is to return a naive datetime.

[Mariusz Felisiak]

Regression in 1487f16f2d29c7aeaf48117d02a1d7bbeafa3d94.

[Hasan Ramezani]

​PR

[Claude Paroz]

Repeating what I said on the PR. In my opinion, even if USE_TZ is False, parsing a datetime including timezone information should really keep its timezone. So I'd rather add an admonition to the docs.

[Carlton Gibson]

So this caused a test failure on Django-Filter.

I've adjusted the test case there to account for the new behaviour.

​https://github.com/carltongibson/django-filter/pull/1226

-    @override_settings(USE_TZ=False)
     def test_clean(self):
         w = RangeWidget()
         f = IsoDateTimeRangeField(widget=w)
-        self.assertEqual(
-            f.clean(['2015-01-01T10:30:01.123000+01:00', '2015-01-10T08:45:02.345000+01:00']),
-            slice(datetime(2015, 1, 1, 9, 30, 1, 123000),
-                  datetime(2015, 1, 10, 7, 45, 2, 345000)))
+        expected = slice(
+            datetime(2015, 1, 1, 9, 30, 1, 123000, tzinfo=timezone.utc),
+            datetime(2015, 1, 10, 7, 45, 2, 345000, tzinfo=timezone.utc)
+        )
+        actual = f.clean(['2015-01-01T10:30:01.123000+01:00', '2015-01-10T08:45:02.345000+01:00'])
+        self.assertEqual(expected, actual)

Let's assume we'll go with the docs change.

[Hasan Ramezani]

Ok, I will create a PR for doc change.

[Hasan Ramezani]

I created a new ​PR to change the release note and mention the behavior of forms.DateTimeField per ​Carlton comment.

[GitHub <noreply@…>]

In 643207ef:

Fixed #31608 -- Doc'd that form ISO 8601 datetime parsing always retains tzinfo.

[Carlton Gibson <carlton.gibson@…>]

In a6c773a:

[3.1.x] Fixed #31608 -- Doc'd that form ISO 8601 datetime parsing always retains tzinfo.

Backport of 643207efaebbff4e7c3ebcbf9ca49fb6197137e1 from master