Fixed #17742 -- Handled aware datetimes in DateField

Converted aware datetimes to the default time zone before using them
in the context of a DateField.

django/db/models/fields/__init__.py

@@ -667,6 +667,11 @@ class DateField(Field):
         if value is None:
             return value
         if isinstance(value, datetime.datetime):
+            if settings.USE_TZ and timezone.is_aware(value):
+                # Convert aware datetimes to the current time zone
+                # before casting them to dates (#17742).
+                default_timezone = timezone.get_default_timezone()
+                value = timezone.make_naive(value, default_timezone)
             return value.date()
         if isinstance(value, datetime.date):
             return value

tests/modeltests/timezones/models.py

@@ -16,3 +16,6 @@ class SessionEvent(models.Model):
 class Timestamp(models.Model):
     created = models.DateTimeField(auto_now_add=True)
     updated = models.DateTimeField(auto_now=True)
+
+class AllDayEvent(models.Model):
+    day = models.DateField()

tests/modeltests/timezones/tests.py

@@ -23,7 +23,7 @@ from django.utils.tzinfo import FixedOffset
 from django.utils.unittest import skipIf, skipUnless
 
 from .forms import EventForm, EventSplitForm, EventModelForm
-from .models import Event, MaybeEvent, Session, SessionEvent, Timestamp
+from .models import Event, MaybeEvent, Session, SessionEvent, Timestamp, AllDayEvent
 
 
 # These tests use the EAT (Eastern Africa Time) and ICT (Indochina Time)
@@ -244,6 +244,14 @@ class LegacyDatabaseTests(TestCase):
                 [event],
                 transform=lambda d: d)
 
+    def test_filter_date_field_with_aware_datetime(self):
+        # Regression test for #17742
+        day = datetime.date(2011, 9, 1)
+        event = AllDayEvent.objects.create(day=day)
+        # This is 2011-09-02T01:30:00+03:00 in EAT
+        dt = datetime.datetime(2011, 9, 1, 22, 30, 0, tzinfo=UTC)
+        self.assertTrue(AllDayEvent.objects.filter(day__gte=dt).exists())
+
 
 @override_settings(TIME_ZONE='Africa/Nairobi', USE_TZ=True)
 class NewDatabaseTests(TestCase):
@@ -456,8 +464,16 @@ class NewDatabaseTests(TestCase):
                 [event],
                 transform=lambda d: d)
 
+    def test_filter_date_field_with_aware_datetime(self):
+        # Regression test for #17742
+        day = datetime.date(2011, 9, 1)
+        event = AllDayEvent.objects.create(day=day)
+        # This is 2011-09-02T01:30:00+03:00 in EAT
+        dt = datetime.datetime(2011, 9, 1, 22, 30, 0, tzinfo=UTC)
+        self.assertFalse(AllDayEvent.objects.filter(day__gte=dt).exists())
+
     def test_null_datetime(self):
-        # Regression for #17294
+        # Regression test for #17294
         e = MaybeEvent.objects.create()
         self.assertEqual(e.dt, None)