Commit c56c42b5 authored by Jozef Knaperek's avatar Jozef Knaperek Committed by Anssi Kääriäinen
Browse files

Fixed #22967 -- Made Model._do_update consistent 

Made _do_update behave more strictly according to its docs,
including a corner case when specific concurent updates are
executed and select_on_save is set.
parent d647764a

django/db/models/base.py

+8 −2
Original line number Diff line number Diff line
@@ -757,8 +757,14 @@ class Model(six.with_metaclass(ModelBase)): 
            return update_fields is not None or filtered.exists()

        if self._meta.select_on_save and not forced_update:

            if filtered.exists():

                filtered._update(values)

                return True

                # It may happen that the object is deleted from the DB right after

                # this check, causing the subsequent UPDATE to return zero matching

                # rows. The same result can occur in some rare cases when the

                # database returns zero despite the UPDATE being executed

                # successfully (a row is matched and updated). In order to

                # distinguish these two cases, the object's existence in the

                # database is again checked for if the UPDATE query returns 0.

                return filtered._update(values) > 0 or filtered.exists()

            else:

                return False

        return filtered._update(values) > 0

tests/basic/tests.py

+1 −1
Original line number Diff line number Diff line
@@ -701,7 +701,7 @@ class SelectOnSaveTests(TestCase): 
        try:

            Article._base_manager.__class__ = FakeManager

            asos = ArticleSelectOnSave.objects.create(pub_date=datetime.now())

            with self.assertNumQueries(2):

            with self.assertNumQueries(3):

                asos.save()

                self.assertTrue(FakeQuerySet.called)

            # This is not wanted behavior, but this is how Django has always