Why django does not validate email in CustomUser model? - django

Question

I had the following custom user model:
class CustomUser(AbstractUser):
"""User model."""
username = None
email = models.EmailField(unique=True)
USERNAME_FIELD = 'email'
REQUIRED_FIELDS = []
objects = UserManager()
I was under the impression that I would at least get some errors if I tried to create a CustomUser with an invalid email. However, I have the following line it my unit tests:
CustomUser.objects.create_user(email='dave') # creates user!
Shouldn't the above make django throw an error, since 'dave' is clearly not an email? I know I can write a validator, but shouldn't there be already no need to do so?
Here's the UserManager:
class UserManager(BaseUserManager):
"""Define a model manager for User model with no username field."""
use_in_migrations = True
def _create_user(self, email, password, **extra_fields):
"""Create and save a User with the given email and password."""
if not email:
raise ValueError('The given email must be set')
email = self.normalize_email(email)
user = self.model(email=email, **extra_fields)
user.set_password(password)
user.save()
return user
def create_user(self, email, password=None, **extra_fields):
"""Create and save a regular User with the given email and password."""
extra_fields.setdefault('is_staff', False)
extra_fields.setdefault('is_superuser', False)
return self._create_user(email, password, **extra_fields)
Update: CustomUser(email='dave').clean_fields(), however, will throw the following error as expected: (but I am still curious what's up with my original question)
ValidationError: {'password': ['This field cannot be blank.'], 'email': ['Enter a valid email address.']}

Answer 1

Django does not run validators automatically outside of ModelForm's.
So when you do this:
CustomUser.objects.create_user(email='dave') # creates user!
The EmailField's validators (i.e. EmailValidator) will not be run. An error will only be thrown if the database has an issue with the value you are trying to assign. In this case it won't, because under the hood an EmailField is identical to a CharField and you're passing it a string ('dave').
How validators are run (Django docs):
Note that validators will not be run automatically when you save a model, but if you are using a ModelForm, it will run your validators on any fields that are included in your form.
I can understand the confusion. Your intuition is telling you that something defined in the models will be enforced by the ORM regardless of how it's represented in the database. The reality is that a lot of the Model field options are only used in forms (blank, choices, editable, help_text etc.).

Answer 2

From the source, the class AbstractUser doesn't define a validator for the emailfield, but one for username.
So if you want a validation from the model's field, you have to do it yourself.
(and overwritte the username if you want to change it)