#36207: refresh_from_db() doesn't refresh ForeignObject relations
-------------------------------------+-------------------------------------
Reporter: Jacob Walls | Owner: (none)
Type: Bug | Status: new
Component: Database layer | Version: 5.2
(models, ORM) |
Severity: Release blocker | Resolution:
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Old description:
> Although it's an internal API `ForeignObject` is now
> [https://docs.djangoproject.com/en/5.2/topics/composite-primary-key
> /#composite-primary-keys-and-relations quasi-public]. When trying it out
> in a non-composite-pk situation I found that `refresh_from_db()` didn't
> clear out a related ForeignObject.
>
> Here is a rough test using the composite_pk models:
> {{{#!diff
> diff --git a/tests/composite_pk/test_models.py
> b/tests/composite_pk/test_models.py
> index 27157a52ad..fdf58d1621 100644
> --- a/tests/composite_pk/test_models.py
> +++ b/tests/composite_pk/test_models.py
> @@ -155,3 +155,9 @@ class CompositePKModelsTests(TestCase):
> self.assertEqual(4, token.permission_set.count())
> self.assertEqual(4, user.permission_set.count())
> self.assertEqual(4, comment.permission_set.count())
> +
> + def test_refresh_foreign_object(self):
> + self.comment_1.user = self.comment_2.user
> + self.assertEqual(self.comment_1.user, self.comment_2.user)
> + self.comment_1.refresh_from_db()
> + self.assertNotEqual(self.comment_1.user, self.comment_2.user)
> }}}
> ----
> {{{#!py
> ======================================================================
> FAIL: test_refresh_foreign_object
> (composite_pk.test_models.CompositePKModelsTests.test_refresh_foreign_object)
> ----------------------------------------------------------------------
> Traceback (most recent call last):
> File "/Users/.../django/tests/composite_pk/test_models.py", line 163,
> in test_refresh_foreign_object
> self.assertNotEqual(self.comment_1.user, self.comment_2.user)
> ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> AssertionError: <User: User object ((1, 1))> == <User: User object ((1,
> 1))>
>
> ----------------------------------------------------------------------
> Ran 1 test in 0.006s
>
> FAILED (failures=1)
> }}}
New description:
Although it's an internal API `ForeignObject` is now
[https://docs.djangoproject.com/en/5.2/topics/composite-primary-key
/#composite-primary-keys-and-relations quasi-public]. When trying it out
in a non-composite-pk situation I found that `refresh_from_db()` didn't
clear out a related ForeignObject.
Here is a rough test using the composite_pk models (EDIT: prior version of
test wasn't demonstrating anything):
{{{#!diff
diff --git a/tests/composite_pk/test_models.py
b/tests/composite_pk/test_models.py
index 27157a52ad..7cd97a31a9 100644
--- a/tests/composite_pk/test_models.py
+++ b/tests/composite_pk/test_models.py
@@ -155,3 +155,8 @@ class CompositePKModelsTests(TestCase):
self.assertEqual(4, token.permission_set.count())
self.assertEqual(4, user.permission_set.count())
self.assertEqual(4, comment.permission_set.count())
+
+ def test_refresh_foreign_object(self):
+ self.comment_1.user = None
+ self.comment_1.refresh_from_db()
+ self.assertEqual(self.comment_1.user, self.user_1)
}}}
----
{{{#!py
E
======================================================================
ERROR: test_refresh_foreign_object
(composite_pk.test_models.CompositePKModelsTests.test_refresh_foreign_object)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/Users/.../django/tests/composite_pk/test_models.py", line 161, in
test_refresh_foreign_object
self.comment_1.refresh_from_db()
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
File "/Users/.../py313/lib/python3.13/site-
packages/django/db/models/base.py", line 737, in refresh_from_db
db_instance = db_instance_qs.get()
File "/Users/.../py313/lib/python3.13/site-
packages/django/db/models/query.py", line 633, in get
raise self.model.DoesNotExist(
"%s matching query does not exist." % self.model._meta.object_name
)
composite_pk.models.tenant.Comment.DoesNotExist: Comment matching query
does not exist.
----------------------------------------------------------------------
Ran 1 test in 0.008s
FAILED (errors=1)
}}}
--
Comment (by Jacob Walls):
The variant where I found this didn't cause `refresh_from_db()` to throw,
it just silently kept the old value. (This was with a nullable
ForeignObject.)
--
Ticket URL: <https://code.djangoproject.com/ticket/36207#comment:1>
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