[Django] #35580: System check fields.E300 does not allow for related fields involving auto_created through models.

[Django]

#35580: System check fields.E300 does not allow for related fields involving
auto_created through models.
-------------------------------------+-------------------------------------
Reporter: brucejwb | Type: Bug
Status: new | Component: Database
| layer (models, ORM)
Version: 5.1 | Severity: Normal
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
-------------------------------------+-------------------------------------
The model system checks will raise the fields.E300 error if you make an
auto_created through model the target of a related field. Here is an
example of models that will trigger this error:


{{{
class E300TestModelA(models.Model):
pass

class E300TestModelB(models.Model):
many_to_many_rel = models.ManyToManyField(E300TestModelA)

class E300TestModelC(models.Model):
one_to_one_rel =
models.OneToOneField("check_framework.E300TestModelB_many_to_many_rel",
on_delete=models.CASCADE)
}}}


I realize this might be an unusual thing to do, however I have a use case
that requires this and thought I would create this ticket in case others
agree that this should be changed. I will create a pull request shortly.
--
Ticket URL: <https://code.djangoproject.com/ticket/35580>
Django <https://code.djangoproject.com/>
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[Django]

#35580: System check fields.E300 does not allow for related fields involving
auto_created through models.
-------------------------------------+-------------------------------------

Reporter: brucejwb | Owner: brucejwb
Type: Bug | Status: assigned
Component: Database layer | Version: 5.1
(models, ORM) |
Severity: Normal | Resolution:

Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
-------------------------------------+-------------------------------------

Changes (by brucejwb):

* owner: (none) => brucejwb
* status: new => assigned

--
Ticket URL: <https://code.djangoproject.com/ticket/35580#comment:1>

[Django]

#35580: System check fields.E300 does not allow for related fields involving
auto_created through models.
-------------------------------------+-------------------------------------
Reporter: brucejwb | Owner: brucejwb
Type: Bug | Status: assigned
Component: Database layer | Version: 5.1
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage:
| Unreviewed

Has patch: 1 | Needs documentation: 0

Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
-------------------------------------+-------------------------------------
Changes (by brucejwb):

* has_patch: 0 => 1

--
Ticket URL: <https://code.djangoproject.com/ticket/35580#comment:2>

[Django]

#35580: System check fields.E300 does not allow for related fields involving
auto_created through models.
-------------------------------------+-------------------------------------

Reporter: brucejwb | Owner: (none)
Type: Bug | Status: new

Component: Database layer | Version: 5.1
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage:
| Unreviewed
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
-------------------------------------+-------------------------------------
Changes (by brucejwb):

* owner: brucejwb => (none)
* status: assigned => new

--
Ticket URL: <https://code.djangoproject.com/ticket/35580#comment:3>

[Django]

#35580: System check fields.E300 does not allow for related fields involving
auto_created through models.
-------------------------------------+-------------------------------------
Reporter: brucejwb | Owner: (none)
Type: Bug | Status: new
Component: Database layer | Version: 5.1
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage:
| Unreviewed
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
-------------------------------------+-------------------------------------

Comment (by brucejwb):

I created a pull request with a fix for the bug and a regression test.
--
Ticket URL: <https://code.djangoproject.com/ticket/35580#comment:4>