integrate django password validators with django rest framework validate_password

Like you mentioned, when you validate the password in validate_password method using UserAttributeSimilarityValidator validator, you don’t have the user object.

What I suggest that instead of doing field-level validation, you shall perform object-level validation by implementing validate method on the serializer:

import sys
from django.core import exceptions
import django.contrib.auth.password_validation as validators

class RegisterUserSerializer(serializers.ModelSerializer):

     # rest of the code

     def validate(self, data):
         # here data has all the fields which have validated values
         # so we can create a User instance out of it
         user = User(**data)
         
         # get the password from the data
         password = data.get('password')
         
         errors = dict() 
         try:
             # validate the password and catch the exception
             validators.validate_password(password=password, user=user)
         
         # the exception raised here is different than serializers.ValidationError
         except exceptions.ValidationError as e:
             errors['password'] = list(e.messages)
         
         if errors:
             raise serializers.ValidationError(errors)
          
         return super(RegisterUserSerializer, self).validate(data)