Fixed #24263 -- Prevented extra queries on BaseDateDetailView with a custom queryset.

Thanks jekka-ua for the report and patch.

django/views/generic/dates.py

@@ -648,7 +648,7 @@ class BaseDateDetailView(YearMixin, MonthMixin, DayMixin, DateMixin, BaseDetailV
                                  day, self.get_day_format())
 
         # Use a custom queryset if provided
-        qs = queryset or self.get_queryset()
+        qs = self.get_queryset() if queryset is None else queryset
 
         if not self.get_allow_future() and date > datetime.date.today():
             raise Http404(_(

tests/generic_views/test_dates.py

@@ -638,6 +638,10 @@ class DateDetailViewTests(TestCase):
             '/dates/books/get_object_custom_queryset/2008/oct/01/1/')
         self.assertEqual(res.status_code, 404)
 
+    def test_get_object_custom_queryset_numqueries(self):
+        with self.assertNumQueries(1):
+            self.client.get('/dates/books/get_object_custom_queryset/2006/may/01/2/')
+
     def test_datetime_date_detail(self):
         bs = BookSigning.objects.create(event_date=datetime.datetime(2008, 4, 2, 12, 0))
         res = self.client.get('/dates/booksignings/2008/apr/2/%d/' % bs.pk)