manage createsuperuser too restrictive

[Matthew Pava]

I have a custom user model inheriting from AbstractUser. I set username = None because I don't care about usernames. I care about emails. Anyway, whenever I do that, I get an error message from the manage createsuperuser command.

For example:

TypeError: UserManager.create_superuser() missing 1 required positional argument: 'username'
ValueError: The given username must be set
TypeError: StudentManager._create_user() takes from 1 to 3 positional arguments but 4 were given

This has forced me to customize the UserManager:

class MyUserManager(UserManager):
    def _create_user(self, username=None, email=None, password=None, **extra_fields):
        email = self.normalize_email(email)
        user = self.model(email=email, **extra_fields)
        user.password = make_password(password)
        user.save(using=self._db)
        return user

    def create_superuser(self, email=None, password=None, **extra_fields):
        super().create_superuser(email, password, **extra_fields)

My rationale for not having or requiring a username is that all valid email addresses are unique. I think the createsuperuser command ought to be more lenient in regard to the username field.

[Mariusz Felisiak]

Duplicate of #26412.