#33512: Creating a child instance with a parent containing
DateTimeField(auto_add_now=True) raises IntegrityError.
-------------------------------------+-------------------------------------
Reporter: Eriks K | Owner: nobody
Type: Bug | Status: closed
Component: Database layer | Version: 4.0
(models, ORM) |
Severity: Normal | Resolution: duplicate
Keywords: auto_add_now | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Changes (by Mariusz Felisiak):
* status: new => closed
* resolution: => duplicate
Old description:
> Description:
> When creating Model object which inherits from other Model which has
> `DateTimeField` with `auto_add_now=True` and passing `parent_ptr_id`
> value, then Django tries to update base Model by setting the auto_now_add
> field to NUL (although the field is null=False)
>
> Expected result:
> ChildModel instance created with a link to ParentModel.
>
> Code examples:
> `models.py`
> {{{
> class ParentModel(models.Model):
> created = models.DateTimeField(auto_now_add=True)
> modified = models.DateTimeField(auto_now=True)
>
> class ChildModel(SomeBaseModel):
> some_field = models.CharField(max_length=12)
> }}}
>
> `manage.py shell`
> {{{
> from app.models import ParentModel, ChildModel
> parent_object = ParentModel.objects.create() # OK
> ChildModel.objects.create() # OK
> ChildModel.objects.create(parentmodel_ptr=parent_object) #
> IntegrityError
> }}}
>
> Actual result:
> Django tries to update ParentModel's `created` with NULL
> {{{
> UPDATE "app_parentmodel" SET "created" = NULL, "modified" = ? WHERE
> "app_parentmodel"."id" = ?
> }}}
> And raises
> {{{
> django.db.utils.IntegrityError: NOT NULL constraint failed:
> app_parentmodel.created
> }}}
>
> Noticed in Django 2.2, reproduced in 3.2 and 4.0. with both Postgres and
> SQlite database backends.
> [https://github.com/eeriks/django-demo Demo project on GitHub] to
> reproduce bug.
New description:
Description:
When creating Model object which inherits from other Model which has
`DateTimeField` with `auto_add_now=True` and passing `parent_ptr_id`
value, then Django tries to update base Model by setting the auto_now_add
field to NUL (although the field is null=False)
Expected result:
ChildModel instance created with a link to ParentModel.
Code examples:
`models.py`
{{{
class ParentModel(models.Model):
created = models.DateTimeField(auto_now_add=True)
modified = models.DateTimeField(auto_now=True)
class ChildModel(ParentModel):
some_field = models.CharField(max_length=12)
}}}
`manage.py shell`
{{{
from app.models import ParentModel, ChildModel
parent_object = ParentModel.objects.create() # OK
ChildModel.objects.create() # OK
ChildModel.objects.create(parentmodel_ptr=parent_object) # IntegrityError
}}}
Actual result:
Django tries to update ParentModel's `created` with NULL
{{{
UPDATE "app_parentmodel" SET "created" = NULL, "modified" = ? WHERE
"app_parentmodel"."id" = ?
}}}
And raises
{{{
django.db.utils.IntegrityError: NOT NULL constraint failed:
app_parentmodel.created
}}}
Noticed in Django 2.2, reproduced in 3.2 and 4.0. with both Postgres and
SQlite database backends.
[https://github.com/eeriks/django-demo Demo project on GitHub] to
reproduce bug.
--
Comment:
Thanks for the report! It looks like a different scenario for the same
issue as described in #24539.
--
Ticket URL: <https://code.djangoproject.com/ticket/33512#comment:1>
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