Commit b825ec38 authored by Claude Paroz's avatar Claude Paroz
Browse files

[1.8.x] Fixed #24418 -- Prevented crash in refresh_from_db with null fk 

Thanks Johannes Lerch for the report, Tim Graham for the test case,
and Simon Charette for the review.
Backport of 5cf96b49 from master.
parent 9d6f0dce

django/db/models/base.py

+1 −1
Original line number Diff line number Diff line
@@ -629,7 +629,7 @@ class Model(six.with_metaclass(ModelBase)): 
            if field.rel and field.get_cache_name() in self.__dict__:

                rel_instance = getattr(self, field.get_cache_name())

                local_val = getattr(db_instance, field.attname)

                related_val = getattr(rel_instance, field.related_field.attname)

                related_val = None if rel_instance is None else getattr(rel_instance, field.related_field.attname)

                if local_val != related_val:

                    del self.__dict__[field.get_cache_name()]

        self._state.db = db_instance._state.db

tests/basic/tests.py

+7 −0
Original line number Diff line number Diff line
@@ -736,6 +736,13 @@ class ModelRefreshTests(TestCase): 
            self.assertFalse(hasattr(s3_copy.selfref, 'touched'))

            self.assertEqual(s3_copy.selfref, s2)



    def test_refresh_null_fk(self):

        s1 = SelfRef.objects.create()

        s2 = SelfRef.objects.create(selfref=s1)

        s2.selfref = None

        s2.refresh_from_db()

        self.assertEqual(s2.selfref, s1)



    def test_refresh_unsaved(self):

        pub_date = self._truncate_ms(datetime.now())

        a = Article.objects.create(pub_date=pub_date)