Django替换默认用户模型后注册报错：AttributeError: Manager不可用

注册新用户并添加到组时出现错误：AttributeError: Manager isn't available; 'auth.User' has been swapped for 'main.CustomUser'，自修改用户模型（添加point字段并执行迁移）后注册功能失效。

相关代码 #

models.py #

class CustomUser(AbstractUser):
    point = models.IntegerField(default=0)

class App(models.Model):
    appname = models.CharField(max_length=255)
    link = models.CharField(max_length=100)
    category= models.CharField(max_length=100)
    subcategory = models.CharField(max_length=100)
    points = models.IntegerField()
    created_at = models.DateTimeField(auto_now_add=True, null=True)
    appicon = models.ImageField(upload_to='icon/')

    def __str__(self):
        return self.appname

注册视图 #

def sign_up(request):
    if request.method == "POST":
        form = RegisterForm(request.POST)
        if form.is_valid():
            user = form.save()
            user_group, created = Group.objects.get_or_create(name='user')
            user.groups.add(user_group)
            login(request, user)
            return redirect('/app')
    else:
        form = RegisterForm()
    return render(request,'registration/signup.html', {'form':form})

settings.py配置 #

AUTH_USER_MODEL = 'main.CustomUser'

报错回溯 #

Internal Server Error: /app/signup/
Traceback (most recent call last):
  File "D:\01 tasks\pro 2 and try outs\django main\venv\Lib\site-packages\django\core\handlers\exception.py", line 55, in inner
    response = get_response(request)
               ^^^^^^^^^^^^^^^^^^^^^
  File "D:\01 tasks\pro 2 and try outs\django main\venv\Lib\site-packages\django\core\handlers\base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)    
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^    
  File "D:\01 tasks\pro 2 and try outs\django main\main\views.py", line 87, in sign_up
    if form.is_valid():
       ^^^^^^^^^^^^^^^
  File "D:\01 tasks\pro 2 and try outs\django main\venv\Lib\site-packages\django\forms\forms.py", line 197, in is_valid
    return self.is_bound and not self.errors
                                 ^^^^^^^^^^^
  File "D:\01 tasks\pro 2 and try outs\django main\venv\Lib\site-packages\django\forms\forms.py", line 192, in errors
    self.full_clean()
  File "D:\01 tasks\pro 2 and try outs\django main\venv\Lib\site-packages\django\forms\forms.py", line 327, in full_clean
    self._clean_fields()
  File "D:\01 tasks\pro 2 and try outs\django main\venv\Lib\site-packages\django\forms\forms.py", line 342, in _clean_fields
    value = getattr(self, "clean_%s" % name)()
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\01 tasks\pro 2 and try outs\django main\venv\Lib\site-packages\django\contrib\auth\forms.py", line 163, in clean_username
    and self._meta.model.objects.filter(username__iexact=username).exists()    
        ^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\01 tasks\pro 2 and try outs\django main\venv\Lib\site-packages\django\db\models\manager.py", line 196, in __get__
    raise AttributeError(
AttributeError: Manager isn't available; 'auth.User' has been swapped for 'main.CustomUser'

错误根源是你使用的RegisterForm大概率是默认的UserCreationForm，它硬关联了auth.User模型，而你已经在settings中替换为自定义的CustomUser，导致表单验证时调用了已被弃用的auth.User的manager。

解决步骤：

1. 自定义注册表单
   在你的app下创建forms.py，编写适配自定义用户模型的表单：

from django.contrib.auth.forms import UserCreationForm
from django.contrib.auth import get_user_model

class RegisterForm(UserCreationForm):
    class Meta:
        model = get_user_model()  # 动态获取当前配置的用户模型
        fields = ('username', 'email', 'password1', 'password2')  # 根据需求添加字段

2. 更新视图导入
   确保视图中导入的是你自定义的RegisterForm，而不是默认的表单：

from .forms import RegisterForm  # 替换原来的导入

3. 验证迁移
   确保所有迁移已正确执行：

python manage.py makemigrations
python manage.py migrate

这样修改后，表单会正确关联你的CustomUser模型，验证时调用正确的manager，错误即可解决。用户添加组的逻辑无需修改，因为AbstractUser已经自带groups关联字段，和Group模型的交互是正常的。

内容的提问来源于stack exchange，提问作者rohit10