#33902: UniqueConstraint: 'F' object has no attribute 'flatten'
-------------------------------------+-------------------------------------
Reporter: | Owner: nobody
gardenerik |
Type: Bug | Status: new
Component: Database | Version: 4.1
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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When using UniqueConstraint with field names in expressions in Django 4.1,
an error is raised when the model is saved:
{{{
Traceback (most recent call last):
File "/usr/local/lib/python3.10/site-
packages/django/core/handlers/exception.py", line 55, in inner
response = get_response(request)
File "/usr/local/lib/python3.10/site-
packages/django/core/handlers/base.py", line 197, in _get_response
response = wrapped_callback(request, *callback_args,
**callback_kwargs)
File "/usr/local/lib/python3.10/site-
packages/django/contrib/admin/options.py", line 686, in wrapper
return self.admin_site.admin_view(view)(*args, **kwargs)
File "/usr/local/lib/python3.10/site-
packages/django/utils/decorators.py", line 133, in _wrapped_view
response = view_func(request, *args, **kwargs)
File "/usr/local/lib/python3.10/site-
packages/django/views/decorators/cache.py", line 62, in _wrapped_view_func
response = view_func(request, *args, **kwargs)
File "/usr/local/lib/python3.10/site-
packages/django/contrib/admin/sites.py", line 242, in inner
return view(request, *args, **kwargs)
File "/usr/local/lib/python3.10/site-
packages/django/contrib/admin/options.py", line 1890, in add_view
return self.changeform_view(request, None, form_url, extra_context)
File "/usr/local/lib/python3.10/site-
packages/django/utils/decorators.py", line 46, in _wrapper
return bound_method(*args, **kwargs)
File "/usr/local/lib/python3.10/site-
packages/django/utils/decorators.py", line 133, in _wrapped_view
response = view_func(request, *args, **kwargs)
File "/usr/local/lib/python3.10/site-
packages/django/contrib/admin/options.py", line 1750, in changeform_view
return self._changeform_view(request, object_id, form_url,
extra_context)
File "/usr/local/lib/python3.10/site-
packages/django/contrib/admin/options.py", line 1796, in _changeform_view
form_validated = form.is_valid()
File "/usr/local/lib/python3.10/site-packages/django/forms/forms.py",
line 205, in is_valid
return self.is_bound and not self.errors
File "/usr/local/lib/python3.10/site-packages/django/forms/forms.py",
line 200, in errors
self.full_clean()
File "/usr/local/lib/python3.10/site-packages/django/forms/forms.py",
line 439, in full_clean
self._post_clean()
File "/usr/local/lib/python3.10/site-packages/django/forms/models.py",
line 492, in _post_clean
self.instance.full_clean(exclude=exclude, validate_unique=False)
File "/usr/local/lib/python3.10/site-packages/django/db/models/base.py",
line 1491, in full_clean
self.validate_constraints(exclude=exclude)
File "/usr/local/lib/python3.10/site-packages/django/db/models/base.py",
line 1442, in validate_constraints
constraint.validate(model_class, self, exclude=exclude, using=using)
File "/usr/local/lib/python3.10/site-
packages/django/db/models/constraints.py", line 329, in validate
for expr in expression.flatten():
AttributeError: 'F' object has no attribute 'flatten'
}}}
The culprit is most probably the new constraint validation (call to
self.validate_constraints in the traceback).
This is excerpt from the model in question:
{{{
class Model:
class Meta:
constraints = (
UniqueConstraint(
"field1",
"field2",
name="some_constraint_name",
),
)
}}}
Please note, that I am not using the `fields` keyword argument, but the
positional `expressions`.
I can confirm that the same model works in Django 4.0.7.
--
Ticket URL: <https://code.djangoproject.com/ticket/33902>
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