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Code Issues 32 Releases Wiki Activity

Fixed #22967 -- Made Model._do_update consistent

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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.
This commit is contained in:
Jozef Knaperek 2014-07-11 22:11:04 +02:00 committed by Anssi Kääriäinen
parent d647764a53
commit c56c42b5c0
2 changed files with 9 additions and 3 deletions
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10
django/db/models/base.py
View File

@ -757,8 +757,14 @@ class Model(six.with_metaclass(ModelBase)):
return update_fields is not None or filtered.exists() return update_fields is not None or filtered.exists()
if self._meta.select_on_save and not forced_update: if self._meta.select_on_save and not forced_update:
if filtered.exists(): if filtered.exists():
filtered._update(values) # It may happen that the object is deleted from the DB right after
return True # 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: else:
return False return False
return filtered._update(values) > 0 return filtered._update(values) > 0

2
tests/basic/tests.py
View File

@ -701,7 +701,7 @@ class SelectOnSaveTests(TestCase):
try: try:
Article._base_manager.__class__ = FakeManager Article._base_manager.__class__ = FakeManager
asos = ArticleSelectOnSave.objects.create(pub_date=datetime.now()) asos = ArticleSelectOnSave.objects.create(pub_date=datetime.now())
with self.assertNumQueries(2): with self.assertNumQueries(3):
asos.save() asos.save()
self.assertTrue(FakeQuerySet.called) self.assertTrue(FakeQuerySet.called)
# This is not wanted behavior, but this is how Django has always # This is not wanted behavior, but this is how Django has always