定义了一个 Form 类，但是 django 引发了异常，说它没有定义

Question

        aqszzFollowed instructions as on [the page][1]. to customize user profile while using django-allauth. Django/python saying it can't find the "SignupForm" class definition, which is clearly defined in the file forms.py in the users app as in the code below. Anyone has any idea what's going on?

forms.py

from django import forms
from allauth.account.forms import AddEmailForm, BaseSignupForm
from django.core.exceptions import ValidationError
from django.conf import settings
from django.contrib.auth.forms import UserCreationForm, UserChangeForm
from .models import CustomUser

class SignupForm(BaseSignupForm):
    first_name = forms.CharField(max_length=30, label='Firstname')
    last_name = forms.CharField(max_length=150, label='Lastname')

    def signup(self, request, user):
        user.first_name = self.cleaned_data['first_name']
        user.last_name = self.cleaned_data['last_name']
        user.save()

class MyAddEmailForm(AddEmailForm):
    def clean_email(self):
        email = super().clean_email()
        if self.user.emailaddress_set.count() >= settings.USERS_EMAILS_MAX_COUNT:
            raise ValidationError('Number of related emails can be no more than %d.' % settings.USERS_EMAILS_MAX_COUNT)
        return email

class CustomUserCreationForm(UserCreationForm):
    class Meta:
        model = CustomUser
        fields = (...)

class CustomUserChangeForm(UserChangeForm):
    class Meta:
        model = CustomUser
        fields = (...)

错误信息是：

  File "D:\Python\Django\m4ever\users\admin.py", line 4, in <module>
    from .forms import CustomUserCreationForm, CustomUserChangeForm
  File "D:\Python\Django\m4ever\users\forms.py", line 3, in <module>
    from allauth.account.forms import AddEmailForm, BaseSignupForm
  File "C:\Users\Freedom\Anaconda3\envs\myvenv\lib\site-packages\allauth\account\forms.py", line 261, in <module>
    class BaseSignupForm(_base_signup_form_class()):
  File "C:\Users\Freedom\Anaconda3\envs\myvenv\lib\site-packages\allauth\account\forms.py", line 249, in _base_signup_form_class
    fc_classname))
django.core.exceptions.ImproperlyConfigured: Module "users.forms" does not define a "SignupForm" class

Answer 1

一直怀疑与循环导入问题有关。将代码更改为如下所示，问题就消失了。这两个变化是：

1. SignupForm 现在继承自普通 forms.Form 而不是 allauth.account.forms.BaseSignupForm

2. 将“allauth.account.forms import AddEmailForm”从文件的开头移到需要它之前。

仍然希望 Python 和/或 Django-Allauth 方面的专家澄清到底发生了什么。

from django import forms
from django.core.exceptions import ValidationError
from django.conf import settings
from django.contrib.auth.forms import UserCreationForm, UserChangeForm
from .models import CustomUser

class SignupForm(forms.Form):
    first_name = forms.CharField(max_length=30, label='Firstname')
    last_name = forms.CharField(max_length=150, label='Lastname')

    def signup(self, request, user):
        user.first_name = self.cleaned_data['first_name']
        user.last_name = self.cleaned_data['last_name']
        user.save()

from allauth.account.forms import AddEmailForm
class MyAddEmailForm(AddEmailForm):
    def clean_email(self):
        email = super().clean_email()
        if self.user.emailaddress_set.count() >= settings.USERS_EMAILS_MAX_COUNT:
            raise ValidationError('Number of related emails can be no more than %d.' % settings.USERS_EMAILS_MAX_COUNT)
        return email

class CustomUserCreationForm(UserCreationForm):
    class Meta:
        model = CustomUser
        fields = (...)

class CustomUserChangeForm(UserChangeForm):
    class Meta:
        model = CustomUser
        fields = (...)