Django 1.5 custom User model error. "Manager isn't available; User has been swapped"

Question

I extend the django user model as described in the dev doc. I wan't to keep most of the original User model features so I extend the AbstractUser class. I've defined in settings.py:

AUTH_USER_MODEL = 'myapp.CustomUser'

My user class:

class CustomUser(AbstractUser):
  custom_field = models.ForeignKey('OtherModel')
  objects = UserManager()

Everything seems to work fine but when I try to make it managed by the admin site:

admin.site.register(CustomUser, UserAdmin)

I get this error on the admin CustomUser creation page (after validation of the password confirmation form):

AttributeError: Manager isn't available; User has been swapped for 'myapp.CustomUser'

The point is that I need this model managed by the admin site in order to have the same creation process as with the original User model (two step process with password validation).

Answer 1

You need only change form for adding user(overwrite clean_username and change User on get_user_model()

Full working example(If you inherited from AbstractUser)

from django.contrib.auth import get_user_model
from django.contrib.auth.admin import UserAdmin
from django.contrib.auth.forms import UserCreationForm, UserChangeForm


class MyUserChangeForm(UserChangeForm):

    class Meta:
        model = get_user_model()

class MyUserCreationForm(UserCreationForm):

    class Meta:
        model = get_user_model()

    def clean_username(self):
        username = self.cleaned_data["username"]
        try:
            get_user_model().objects.get(username=username)
        except get_user_model().DoesNotExist:
            return username
        raise forms.ValidationError(self.error_messages['duplicate_username'])

class MyUserAdmin(UserAdmin):
    form = MyUserChangeForm
    add_form = MyUserCreationForm
    fieldsets = (
        (None, {'fields': [('username', 'password'),]}),
        (_('Personal info'), {'fields': ('first_name', 'last_name', 'email')}),
        (_('Permissions'), {'fields': ('is_active', 'is_staff', 'is_superuser',
                                   'groups', 'user_permissions')}),
        (_('Important dates'), {'fields': ('last_login', 'date_joined')}),
        )

admin.site.register(MyUser, MyUserAdmin)