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

3 files changed, 14 insertions, 2 deletions

diff --git a/django/db/backends/sqlite3/operations.py b/django/db/backends/sqlite3/operations.py
index ad6b2a5a2a..1ab20767c4 100644
--- a/django/db/backends/sqlite3/operations.py
+++ b/django/db/backends/sqlite3/operations.py
@@ -217,7 +217,7 @@ class DatabaseOperations(BaseDatabaseOperations):
         if value is not None:
             if not isinstance(value, datetime.datetime):
                 value = parse_datetime(value)
-            if settings.USE_TZ:
+            if settings.USE_TZ and not timezone.is_aware(value):
                 value = timezone.make_aware(value, self.connection.timezone)
         return value
 
diff --git a/docs/releases/1.10.4.txt b/docs/releases/1.10.4.txt
index 4d3ad91cf4..0f1f70e95d 100644
--- a/docs/releases/1.10.4.txt
+++ b/docs/releases/1.10.4.txt
@@ -19,3 +19,7 @@ Bugfixes
 
 * Made ``Model.delete(keep_parents=True)`` preserve parent reverse
   relationships in multi-table inheritance (:ticket:`27407`).
+
+* Fixed a ``QuerySet.update()`` crash on SQLite when updating a
+  ``DateTimeField`` with an ``F()`` expression and a ``timedelta``
+  (:ticket:`27544`).
diff --git a/tests/timezones/tests.py b/tests/timezones/tests.py
index d95877d227..c50d356074 100644
--- a/tests/timezones/tests.py
+++ b/tests/timezones/tests.py
@@ -14,7 +14,7 @@ from django.contrib.auth.models import User
 from django.core import serializers
 from django.core.exceptions import ImproperlyConfigured
 from django.db import connection, connections
-from django.db.models import Max, Min
+from django.db.models import F, Max, Min
 from django.http import HttpRequest
 from django.template import (
     Context, RequestContext, Template, TemplateSyntaxError, context_processors,
@@ -26,6 +26,7 @@ from django.test import (
 from django.test.utils import requires_tz_support
 from django.urls import reverse
 from django.utils import six, timezone
+from django.utils.timezone import timedelta
 
 from .forms import (
     EventForm, EventLocalizedForm, EventLocalizedModelForm, EventModelForm,
@@ -569,6 +570,13 @@ class NewDatabaseTests(TestCase):
         e = MaybeEvent.objects.create()
         self.assertIsNone(e.dt)
 
+    def test_update_with_timedelta(self):
+        initial_dt = timezone.now().replace(microsecond=0)
+        event = Event.objects.create(dt=initial_dt)
+        Event.objects.update(dt=F('dt') + timedelta(hours=2))
+        event.refresh_from_db()
+        self.assertEqual(event.dt, initial_dt + timedelta(hours=2))
+
 
 @override_settings(TIME_ZONE='Africa/Nairobi', USE_TZ=True)
 class ForcedTimeZoneDatabaseTests(TransactionTestCase):