#33984: Related managers cache gets stale after saving a fetched model with new
PK
-------------------------------------+-------------------------------------
Reporter: joeli | Owner: Bhuvnesh
Type: Bug | Status: assigned
Component: Database layer | Version: 4.1
(models, ORM) |
Severity: Release blocker | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 1
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by Mariusz Felisiak):
I found another regression in caching related manager. The following test
works on Django 4.0 and crashes with
4f8c7fd9d91b35e2c2922de4bb50c8c8066cbbc6:
{{{#!diff
diff --git a/tests/many_to_many/tests.py b/tests/many_to_many/tests.py
index 53e870ddad..770808a92c 100644
--- a/tests/many_to_many/tests.py
+++ b/tests/many_to_many/tests.py
@@ -92,6 +92,27 @@ class ManyToManyTests(TestCase):
a5.authors.remove(user_2.username)
self.assertSequenceEqual(a5.authors.all(), [])
+ def test_related_manager_refresh(self):
+ user_1 = User.objects.create(username="Jean")
+ user_2 = User.objects.create(username="Joe")
+ a5 = Article.objects.create(headline="Django lets you create web
apps easily")
+ a5.authors.add(user_1.username)
+ self.assertSequenceEqual(user_1.article_set.all(), [a5])
+ # Change the username on a different instance of the same user.
+ user_1_from_db = User.objects.get(pk=user_1.pk)
+ self.assertSequenceEqual(user_1_from_db.article_set.all(), [a5])
+ user_1_from_db.username = "Paul"
+ user_1_from_db.save()
+ user_2.username = "Jean"
+ user_2.save()
+ # Add a different article.
+ self.a4.authors.add(user_1_from_db.username)
+ self.assertSequenceEqual(user_1_from_db.article_set.all(),
[self.a4])
+ # Refresh the first instance from DB.
+ user_1.refresh_from_db()
+ self.assertEqual(user_1.username, "Paul")
+ self.assertSequenceEqual(user_1.article_set.all(), [self.a4])
+
def test_add_remove_invalid_type(self):
msg = "Field 'id' expected a number but got 'invalid'."
for method in ["add", "remove"]:
}}}
It shows two issues:
- the second call of `user_1_from_db.article_set.all()` should use a new
username (`Paul`) but it's still using the old one (`Jean`),
- `user_1.refresh_from_db()` doesn't clear cached managers.
I'm going to prepare revert of 4f8c7fd9d91b35e2c2922de4bb50c8c8066cbbc6
and reopen #32980.
--
Ticket URL: <https://code.djangoproject.com/ticket/33984#comment:14>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to django-updates+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/010701838d2fa004-96cd2d47-cb3b-45cd-9aaa-eed15e013347-000000%40eu-central-1.amazonses.com.
