Django 1.11 update_or_create field validation results in different behaviours between create and update_or_create

[Alex Mykyta]

This is an issue related to #27118. Anthony King commented on it but that issue is closed so I am opening a new one. The field validation introduced in 1.11 update_or_create will throw a FieldError if a defaults argument contains a value that is set through an @property.setter on that model. On the other hand create continues to function correctly. Ideally they'd behave consistently.

Here is an example.

# create works, update_or_create does not. Should neither work?
class Choice(models.Model):
        poll = models.ForeignKey(Poll)
        choice_text = models.CharField(max_length=200)
        votes = models.IntegerField(default=0)

        _credit = models.DecimalField('Credit', decimal_places = 5, max_digits=11, null=True)

        @property
        def credit(self):
                return 0 if self._credit is None else self._credit

        @credit.setter
        def credit(self, value):
                self._credit = value


In [7]: mk = Choice.objects.create(credit=123.3, poll_id=1)

In [8]: mk
Out[8]: <Choice: >

In [9]: mk.__dict__
Out[9]:
{'_credit': 123.3,
 '_state': <django.db.models.base.ModelState at 0x1116e3650>,
 'choice_text': u'',
 'id': 2,
 'poll_id': 1,
 'votes': 0}

In [10]: ok = Choice.objects.update_or_create(defaults={'credit':123.3}, poll_id=1)
---------------------------------------------------------------------------
FieldError                                Traceback (most recent call last)
<ipython-input-10-147ffa08785c> in <module>()
----> 1 ok = Choice.objects.update_or_create(defaults={'credit':123.3}, poll_id=1)

/usr/local/lib/python2.7/site-packages/django/db/models/manager.pyc in manager_method(self, *args, **kwargs)
     83         def create_method(name, method):
     84             def manager_method(self, *args, **kwargs):
---> 85                 return getattr(self.get_queryset(), name)(*args, **kwargs)
     86             manager_method.__name__ = method.__name__
     87             manager_method.__doc__ = method.__doc__

/usr/local/lib/python2.7/site-packages/django/db/models/query.pyc in update_or_create(self, defaults, **kwargs)
    474         """
    475         defaults = defaults or {}
--> 476         lookup, params = self._extract_model_params(defaults, **kwargs)
    477         self._for_write = True
    478         with transaction.atomic(using=self.db):

/usr/local/lib/python2.7/site-packages/django/db/models/query.pyc in _extract_model_params(self, defaults, **kwargs)
    530                 "Invalid field name(s) for model %s: '%s'." % (
    531                     self.model._meta.object_name,
--> 532                     "', '".join(sorted(invalid_params)),
    533                 ))
    534         return lookup, params

FieldError: Invalid field name(s) for model Choice: 'credit'.

[Alex Mykyta]

​PR

[Tim Graham]

Please move the pastebin content (which expires in 1 day) to the ticket's description.

The "Ready for checkin" status is set by a patch reviewer, not the patch author.

[Alex Mykyta]

Whoops. Sorry, still figuring out the contribution process.