Re: [Django] #33816: QuerySet.only() after select_related() crash on proxy models. (was: Query.deferred_to_data function does not fetch pk from the model if it is a proxy model.)

[Django]

#33816: QuerySet.only() after select_related() crash on proxy models.
-------------------------------------+-------------------------------------
Reporter: Ipakeev | Owner: nobody
Type: Bug | Status: new
Component: Database layer | Version: 4.0
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Changes (by Mariusz Felisiak):

* stage: Unreviewed => Accepted

Comment:

Thanks for the report. Would you like to prepare a patch? A regression
test is required, e.g.
{{{#!diff
diff --git a/tests/proxy_models/tests.py b/tests/proxy_models/tests.py
index f2f465678b..2081c0cbe3 100644
--- a/tests/proxy_models/tests.py
+++ b/tests/proxy_models/tests.py
@@ -390,6 +390,12 @@ class ProxyModelTests(TestCase):
repr(resp), "<ProxyImprovement: ProxyImprovement:improve
that>"
)

+ def test_select_related_only(self):
+ user = ProxyTrackerUser.objects.create(name="Joe Doe",
status="test")
+ issue = Issue.objects.create(summary="New issue", assignee=user)
+ qs =
Issue.objects.select_related("assignee").only("assignee__status")
+ self.assertEqual(qs.get(), issue)
+
def test_proxy_load_from_fixture(self):
management.call_command("loaddata", "mypeople.json", verbosity=0)
p = MyPerson.objects.get(pk=100)
}}}

> If I replace it by
> `opts = cur_model._meta.concrete_model._meta`
> all works as expected.
I would fix `cur_model` instead:
{{{
cur_model = cur_model._meta.concrete_model
opts = cur_model._meta
}}}

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Ticket URL: <https://code.djangoproject.com/ticket/33816#comment:1>
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