admin disallows saving Null fk to more than one object

[smcoll]

from django.db import models
from django.contrib.auth.models import User

class Contact(models.Model):
    user = models.ForeignKey(User, unique=True, null=True, blank=True)

In the admin, you can't save more than one model with a Null (-------) fk because you get an error: "Contact with this User already exists."

So it's as if Django is treating the "no relation" selection as an FK itself, and since unique=True, no more than one model can have a Null fk.

In my understanding, the model above should allow for any number of Null relations, but only allow one relation per User instance.

Might possibly be related to #9039.

[Karen Tracey]

Unless I am missing something, this is more than related to #9039, it is #9039. Admin uses ModelForms, so problems they exhibit will show up in Admin, and fixing it for ModelForms in general will fix it for Admin, so we don't need two open tickets tracking this.