[Django] #33614: Django's object creation when using GenericForeignKeys results in different ContentType model id's

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Apr 1, 2022, 9:56:04 AM4/1/22

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#33614: Django's object creation when using GenericForeignKeys results in different
ContentType model id's
------------------------------------------------+------------------------
Reporter: Lucas Zocco | Owner: nobody
Type: Bug | Status: new
Component: contrib.contenttypes | Version: 4.0
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
------------------------------------------------+------------------------
I've created a Document model that has a GenericFK to another model,
however I have noticed that the related_type id is different depending on
how the object is created. It seems to be wrong if done in the manner
explained in the official documentation
(https://docs.djangoproject.com/en/4.0/ref/contrib/contenttypes/#generic-
relations-1) where the object is directly assigned to related_object
instead of creating the GenericForeignKey by setting the related_type and
related_id individually.

A small code snippet to illustrate:
{{{
class Document(BaseModel):
related_id = models.UUIDField(
null=True,
blank=True,
db_index=True,
help_text=("The UUID of the origin model, which this flag came
from."),
)
related_type = models.ForeignKey(
ContentType,
null=True,
blank=True,
on_delete=models.SET_NULL,
help_text="Type that the Subject id relates to",
)
related = GenericForeignKey("related_type", "related_id")

doc1 = Document(data=b'',
related=company)

doc2 = Document(data=b'',
related_type=ContentType.objects.get_for_model(company),
related_id=company.id)

print(ContentType.objects.get_for_model(company).id)
>>> 23

print(doc1.related_type.id)
>>> 148

print(doc2.related_type.id)
>>> 23
}}}

For reference: There's no object with id 148 in the ContentTypes table so
I'm not sure where it's getting it from.

--
Ticket URL: <https://code.djangoproject.com/ticket/33614>
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Django

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Apr 1, 2022, 6:07:51 PM4/1/22

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#33614: Django's object creation when using GenericForeignKeys results in different
ContentType model id's

-------------------------------------+-------------------------------------

Reporter: Lucas Zocco | Owner: nobody

Type: Bug | Status: closed
Component: | Version: 4.0
contrib.contenttypes |
Severity: Normal | Resolution: invalid

-------------------------------------+-------------------------------------
Changes (by Simon Charette):

* status: new => closed
* resolution: => invalid

Comment:

I unfortunately cannot reproduce your reported issue on the latest version
of Django with your provided instructions (Defining a `Company` model of
my own with no fields).

Please re-open with a set of instructions that reproduces against a
supported version of Django (e.g. a sample project with a command or test
case that demonstrates an assertion failure).