#28101: Wrong field used for sub query lookup on nested query using to_field
ForeignKey
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Reporter: klette | Owner: nobody
Type: Bug | Status: new
Component: Database | Version: 1.11
layer (models, ORM) |
Severity: Normal | Keywords:
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
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Given the following models:
{{{#!python
class CustomerUser(models.Model):
name = models.CharField(max_length=100)
class Customer(models.Model):
id = models.UUIDField(primary_key=True, default=uuid.uuid4,
editable=False)
customer_number = models.CharField(unique=True, max_length=100)
users = models.ManyToManyField(CustomerUser)
class CustomerProduct(models.Model):
id = models.UUIDField(primary_key=True, default=uuid.uuid4,
editable=False)
customer = models.ForeignKey(
Customer, to_field='customer_number', on_delete=models.PROTECT)
name = models.CharField(max_length=100)
class CustomerPayment(models.Model):
id = models.UUIDField(primary_key=True, default=uuid.uuid4,
editable=False)
product = models.ForeignKey(CustomerProduct, on_delete=models.PROTECT)
}}}
And the tests:
{{{#!python
class SubQueryM2MWithToFieldFkTests(TestCase):
def test_regression(self):
user = CustomerUser.objects.create(name='my user')
customer = Customer.objects.create(customer_number='A123')
customer.users.add(user)
product = CustomerProduct.objects.create(customer=customer,
name='Foo')
payment = CustomerPayment.objects.create(product=product)
products = CustomerProduct.objects.filter(
customer__in=user.customer_set.all())
result = CustomerPayment.objects.filter(product__in=products)
self.assertEquals(result.count(), 1)
self.assertEquals(list(result), [payment])
}}}
One should get the query:
{{{#!sql
SELECT "queries_customerpayment"."id",
"queries_customerpayment"."product_id"
FROM "queries_customerpayment"
WHERE "queries_customerpayment"."product_id" IN (
SELECT V0."id" AS Col1 FROM "queries_customerproduct" V0
WHERE V0."customer_id" IN (
SELECT U0."customer_number" AS Col1
FROM "queries_customer" U0 INNER JOIN "queries_customer_users" U1 ON
(U0."id" = U1."customer_id")
WHERE U1."customeruser_id" = 1))
}}}
But at least 1.11 and master generates:
{{{#!sql
SELECT "queries_customerpayment"."id",
"queries_customerpayment"."product_id"
FROM "queries_customerpayment"
WHERE "queries_customerpayment"."product_id" IN (
SELECT V0."id" AS Col1 FROM "queries_customerproduct" V0
WHERE V0."customer_id" IN (
SELECT U0."id" AS Col1 FROM "queries_customer" U0 INNER JOIN
"queries_customer_users" U1 ON (U0."id" = U1."customer_id")
WHERE U1."customeruser_id" = 1))
}}}
which attempts to match the wrong `Customer`-field to
`CustomerProduct.customer_id`.
I tried to figure out what was going on and the test passes if I add
`print(self)` to `Queryset._prepare_as_filter_value` in the forced pk
block. Quite arbitrary placement of the print, and probably not related to
`_prepare_as_filter_value`. My guess would be that the evaluation of the
inner queryset fixes some field matching some other place - but I'm way
out of my depth here :)
The tests were added directly to `tests/queries/tests.py` and the models
to `tests/queries/models.py` and run using Django's test suite.
Might be related: [https://code.djangoproject.com/ticket/26196]
--
Ticket URL: <https://code.djangoproject.com/ticket/28101>
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