[Python] Django: Adding user to groups in a signal

I created a signal which is supped to do 3 things:

1. Create a User
2. Create the Profile of said user
3. Add User to a Group

Using a signal, steps 1 and 2 work fine but I can't seem to add the user to a group (step 3).

# Signals
@receiver(post_save, sender=User)
def create_user_profile(sender, instance, created, **kwargs):
if created:
Profile.objects.create(user=instance)
group = Group.objects.get(name='generics')
instance.groups.add(group)


Did some debugging and found out that even if I comment out Profile.objects.create(user=instance) I still can't add any groups to instance.

Am I missing anything here? I'm not getting any errors.

Edit 1: This is a custom User model.

from django.contrib.auth.models import AbstractUser

class User(AbstractUser):
first_name = None
last_name = None

class Meta:
verbose_name_plural = 'users'

def __str__(self):
return self.username


I simply moved first_name and last_name to the Profile table. Didn't do anything else as you can see. Users and Profiles are successfully being created so this custom model works just fine.

Although unnecessary, I added instance.save() after adding the group but it still won't work. The admin shows no groups have been added and the the db table core_user_groups is still empty.

Edit 2: Add console test

Even more weird, I tried adding the group using ./manage.py shell and it works fine.

>>> from core.models import User
>>> from django.contrib.auth.models import Group
>>> group = Group.objects.get(pk=1)
>>> group
<Group: generics>
>>> user = User.objects.get(pk=23)
>>> user
<User: sonic>
>>> user.groups.add(group)

# At this point I check the admin and the db and it worked. Hmmm....but how to do it within a signal...

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