Ticket #7448: 7448-datefield-in.patch

django/db/models/fields/__init__.py

@@ -552 +552 @@
             value = [smart_unicode(v) for v in value]
         elif lookup_type in ('exact', 'gt', 'gte', 'lt', 'lte') and hasattr(value, 'strftime'):
             value = value.strftime('%Y-%m-%d')
+        elif lookup_type == 'in':
+            value = [v.strftime('%Y-%m-%d') for v in value]
         else:
             value = smart_unicode(value)
         return Field.get_db_prep_lookup(self, lookup_type, value)