Question

Ok, so I have a model like this:

class Airplane(models.Model):
    tail = models.ForeignKey(Tails)
    wheel = models.CharField(max_length=500,blank=True)
    window = models.CharField(max_length=500,blank=True)

    def clean(self):
        if self.tail and self.wheel and self.window:
            raise ValidationError("Can't have all three, choose tail and one more")

Now if I go to add a new Airplane record using Django admin. If I leave both fields blank and save I get this Django error pointing to the line if self.tail and self.wheel.

DoesNotExist at /admin/MyProject/airplane/add/

Request Method:     POST
Request URL:    http://44.101.44.172:8001/admin/MyProject/airplane/add/
Django Version:     1.2.5
Exception Type:     DoesNotExist
Exception Value:    

Exception Location:     /usr/lib/python2.7/site-packages/django/db/models/fields/related.py in __get__, line 299
Python Executable:  /usr/bin/python
Python Version:     2.7.0

Shouldn’t Django be checking that the required fields are filled in before running clean? In any case, what’s the best way to handle this issue?

Answer 1

Ok, as a workaround I ended up defining a custom form with my validation in admin.py for this model.

I still don’t understand why model.clean gets called before Django has determined that the required fields have been filled in. Oh well.