#16159: ModelForm does not catch unique error with model inheritance of more
than 2
levels
-------------------------------------+-------------------------------------
Reporter: mturtle | Owner: nobody
Type: Bug | Status: new
Milestone: | Component: Database layer
Version: 1.2 | (models, ORM)
Keywords: unique constraint, | Severity: Normal
ModelForm, inheritance | Triage Stage: Unreviewed
Has patch: 0 | Easy pickings: 0
-------------------------------------+-------------------------------------
Ticket #12881 describes the main problem, which was partially fixed.
However, when you have a larger inheritance hierarchy, the form doesn't
catch it in the validation, and instead a unique constraint error is
raised by postgres.
The culprit:
{{{
class A(Model):
username = CharField(max_length=255, unique=True)
class B(A):
pass
class C(B):
pass
}}}
(Note C extends B, and B extends A.)
In Django 1.2.5 in django/db/models/base.py, around line 762, I see the
following:
{{{
fields_with_class = [(self.__class__, self._meta.local_fields)]
for parent_class in self._meta.parents.keys():
fields_with_class.append((parent_class,
parent_class._meta.local_fields))
}}}
When I change `self._meta.parents.keys()` to include the entire chain of
superclasses, the problem is fixed. I don't know the best-practice way of
calculating the chain of superclasses up to but not including Model, but
my dirty hack method of demonstrating this is by changing
`self._meta.parents.keys()` to
`self._meta.get_base_chain(type(self).__bases__[0].__bases__[0])`
--
Ticket URL: <https://code.djangoproject.com/ticket/16159>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To post to this group, send email to django-updates@googlegroups.com.
To unsubscribe from this group, send email to
django-updates+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/django-updates?hl=en.
