Fixed #21186: Fixed regression when using date fields in the admin's list_filter.

Thanks to onlygoldi2201 for the report and to ramiro and apollo13
for the reviews.

django/contrib/admin/filters.py

@@ -303,6 +303,11 @@ class DateFieldListFilter(FieldListFilter):
         else:       # field is a models.DateField
             today = now.date()
         tomorrow = today + datetime.timedelta(days=1)
+        if today.month == 12:
+            next_month = today.replace(year=today.year + 1, month=1, day=1)
+        else:
+            next_month = today.replace(month=today.month + 1, day=1)
+        next_year = today.replace(year=today.year + 1, month=1, day=1)
 
         self.lookup_kwarg_since = '%s__gte' % field_path
         self.lookup_kwarg_until = '%s__lt' % field_path
@@ -318,11 +323,11 @@ class DateFieldListFilter(FieldListFilter):
             }),
             (_('This month'), {
                 self.lookup_kwarg_since: str(today.replace(day=1)),
-                self.lookup_kwarg_until: str(tomorrow),
+                self.lookup_kwarg_until: str(next_month),
             }),
             (_('This year'), {
                 self.lookup_kwarg_since: str(today.replace(month=1, day=1)),
-                self.lookup_kwarg_until: str(tomorrow),
+                self.lookup_kwarg_until: str(next_year),
             }),
         )
         super(DateFieldListFilter, self).__init__(

tests/admin_filters/tests.py

@@ -143,6 +143,11 @@ class ListFiltersTests(TestCase):
         self.today = datetime.date.today()
         self.tomorrow = self.today + datetime.timedelta(days=1)
         self.one_week_ago = self.today - datetime.timedelta(days=7)
+        if self.today.month == 12:
+            self.next_month = self.today.replace(year=self.today.year + 1, month=1, day=1)
+        else:
+            self.next_month = self.today.replace(month=self.today.month + 1, day=1)
+        self.next_year = self.today.replace(year=self.today.year + 1, month=1, day=1)
 
         self.request_factory = RequestFactory()
 
@@ -196,7 +201,7 @@ class ListFiltersTests(TestCase):
                                                 % (self.today, self.tomorrow))
 
         request = self.request_factory.get('/', {'date_registered__gte': self.today.replace(day=1),
-                                                 'date_registered__lt': self.tomorrow})
+                                                 'date_registered__lt': self.next_month})
         changelist = self.get_changelist(request, Book, modeladmin)
 
         # Make sure the correct queryset is returned
@@ -214,10 +219,10 @@ class ListFiltersTests(TestCase):
         self.assertEqual(choice['selected'], True)
         self.assertEqual(choice['query_string'], '?date_registered__gte=%s'
                                                  '&date_registered__lt=%s'
-                                                % (self.today.replace(day=1), self.tomorrow))
+                                                % (self.today.replace(day=1), self.next_month))
 
         request = self.request_factory.get('/', {'date_registered__gte': self.today.replace(month=1, day=1),
-                                                 'date_registered__lt': self.tomorrow})
+                                                 'date_registered__lt': self.next_year})
         changelist = self.get_changelist(request, Book, modeladmin)
 
         # Make sure the correct queryset is returned
@@ -235,7 +240,7 @@ class ListFiltersTests(TestCase):
         self.assertEqual(choice['selected'], True)
         self.assertEqual(choice['query_string'], '?date_registered__gte=%s'
                                                  '&date_registered__lt=%s'
-                                                % (self.today.replace(month=1, day=1), self.tomorrow))
+                                                % (self.today.replace(month=1, day=1), self.next_year))
 
         request = self.request_factory.get('/', {'date_registered__gte': str(self.one_week_ago),
                                                  'date_registered__lt': str(self.tomorrow)})