django - 为什么我会收到 'ImproperlyConfigured' 异常，这意味着循环导入？

Question

我以前遇到过这个问题，但我设法找到了引用的循环导入。我再次面对它，但我找不到问题。

我的项目名称是“sare”，我的 sare/urls.py 如下所示:

from django.contrib import admin
from django.urls import include, path

urlpatterns = [
    path('users/', include('users.urls', namespace='users')),
    path('admin/', admin.site.urls),
]

而 users/urls.py 是这样的:

from django.urls import path
from .views import UsersTableView#, UserCreateView, UserUpdateView, UserDeleteView

app_name = 'users'

urlpatterns = [
    path('table/', UsersTableView.as_view(), name='users_table'),
    # path('create/', UserCreateView.as_view(), name='users_create'),
    # path('update/<int:pk>', UserUpdateView.as_view(), name='users_update'),
    # path('delete/<int:pk>', UserDeleteView.as_view(), name='users_delete'),
]

我的 View 中唯一没有注释的代码是 UsersTableView，它看起来像这样:

from django.contrib.auth.mixins import LoginRequiredMixin, UserPassesTestMixin
from .models import CustomUser
from .tables import UsersTable
from .filters import UserFilter
from .form_helpers import UsersFilterFormHelper
from django.views.generic import CreateView, UpdateView, DeleteView
from .forms import UserForm
from django.urls import reverse_lazy, reverse
from django_tables2.export import ExportMixin
from django_tables2 import RequestConfig,SingleTableView,Table as TableBase
from django_filters import FilterSet


class InitUserMixin(object):
    def __init__(self, *args, **kwargs):
        self.user = kwargs.pop("user", None)
        super(InitUserMixin, self).__init__(*args, **kwargs)


class FilterUserMixin(InitUserMixin, FilterSet):
    pass


class Table(InitUserMixin, TableBase):
    pass


class PagedFilteredTableView(ExportMixin, SingleTableView):
    filter_class = None
    formhelper_class = None
    context_filter_name = 'filter'

    def get_queryset(self, **kwargs):
        qs = super(PagedFilteredTableView, self).get_queryset()
        self.filter = self.filter_class(self.request.GET, queryset=qs, user=self.request.user)
        self.filter.form.helper = self.formhelper_class()
        return self.filter.qs

    def get_table(self, **kwargs):
        table = super(PagedFilteredTableView, self).get_table(user=self.request.user)
        RequestConfig(self.request, paginate={'page': self.kwargs.get('page', 1),
                                              "per_page": self.paginate_by}).configure(table)
        return table

    def get_context_data(self, **kwargs):
        context = super(PagedFilteredTableView, self).get_context_data(**kwargs)
        context[self.context_filter_name] = self.filter
        return context


class UsersTableView(LoginRequiredMixin,PagedFilteredTableView, UserPassesTestMixin):
    model = CustomUser
    table_class = UsersTable
    template_name = 'users/users_table.html'
    paginate_by = 10
    filter_class = UserFilter
    formhelper_class = UsersFilterFormHelper

    def test_func(self):
        if self.request.user.is_superuser:
            return True
        else:
            return False

我试图评论 View 中的所有内容，只写 pass ，但它给出了相同的结果。
我看不到任何循环导入。你看到这段代码有什么问题吗，或者我应该看看其他什么？

Traceback (most recent call last):
  File "C:\Users\Iván\AppData\Local\Programs\Python\Python36\Lib\threading.py", line 916, in _bootstrap_inner
    self.run()
  File "C:\Users\Iván\AppData\Local\Programs\Python\Python36\Lib\threading.py", line 864, in run
    self._target(*self._args, **self._kwargs)
  File "C:\Users\Iván\AppData\Local\Programs\Python\Python36\Lib\site-packages\django\utils\autoreload.py", line 53, in wrapper
    fn(*args, **kwargs)
  File "C:\Users\Iván\AppData\Local\Programs\Python\Python36\Lib\site-packages\django\core\management\commands\runserver.py", line 117, in inner_run
    self.check(display_num_errors=True)
  File "C:\Users\Iván\AppData\Local\Programs\Python\Python36\Lib\site-packages\django\core\management\base.py", line 395, in check
    include_deployment_checks=include_deployment_checks,
  File "C:\Users\Iván\AppData\Local\Programs\Python\Python36\Lib\site-packages\django\core\management\base.py", line 382, in _run_checks
    return checks.run_checks(**kwargs)
  File "C:\Users\Iván\AppData\Local\Programs\Python\Python36\Lib\site-packages\django\core\checks\registry.py", line 72, in run_checks
    new_errors = check(app_configs=app_configs)
  File "C:\Users\Iván\AppData\Local\Programs\Python\Python36\Lib\site-packages\django\core\checks\urls.py", line 13, in check_url_config
    return check_resolver(resolver)
  File "C:\Users\Iván\AppData\Local\Programs\Python\Python36\Lib\site-packages\django\core\checks\urls.py", line 23, in check_resolver
    return check_method()
  File "C:\Users\Iván\AppData\Local\Programs\Python\Python36\Lib\site-packages\django\urls\resolvers.py", line 406, in check
    for pattern in self.url_patterns:
  File "C:\Users\Iván\AppData\Local\Programs\Python\Python36\Lib\site-packages\django\utils\functional.py", line 48, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "C:\Users\Iván\AppData\Local\Programs\Python\Python36\Lib\site-packages\django\urls\resolvers.py", line 596, in url_patterns
    raise ImproperlyConfigured(msg.format(name=self.urlconf_name))
django.core.exceptions.ImproperlyConfigured: The included URLconf 'sare.urls' does not appear to have any patterns in it. If you see valid patterns in the file then the issue is probably caused by a circular import.

编辑:

我的 settings.py 是这样的:

import os

# Build paths inside the project like this: os.path.join(BASE_DIR, ...)
BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))


# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/3.0/howto/deployment/checklist/

# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = '^*5r6l%i-dubv_ur*p06d*rp@d@*dg@4z%&li8#f4ca=h9z-r*'

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = True

ALLOWED_HOSTS = []


# Application definition

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',

    'rest_framework',
    'rest_framework.authtoken',
    'sare',
    'formats',
    'users',
    'crequest',
    'django_tables2',
    'django_filters',

    #'allauth',  # registration
    #'allauth.account',  # registration
    #'allauth.socialaccount',  # registration
]

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

ROOT_URLCONF = 'sare.urls'

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
            ],
        },
    },
]

WSGI_APPLICATION = 'sare.wsgi.application'


# Database
# https://docs.djangoproject.com/en/3.0/ref/settings/#databases

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
    }
}


# Password validation
# https://docs.djangoproject.com/en/3.0/ref/settings/#auth-password-validators

AUTH_PASSWORD_VALIDATORS = [
    {
        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
    },
]


# Internationalization
# https://docs.djangoproject.com/en/3.0/topics/i18n/

LANGUAGE_CODE = 'en-us'

TIME_ZONE = 'UTC'

USE_I18N = True

USE_L10N = True

USE_TZ = True


# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/3.0/howto/static-files/

STATIC_URL = '/static/'

AUTH_USER_MODEL = 'users.CustomUser'

Answer 1

注意您 View 中的 MRO(方法解析顺序)class UsersTableView(LoginRequiredMixin, PagedFilteredTableView, UserPassesTestMixin) ，mixin 应始终位于要考虑的层次结构的开头。

否则，要查看循环导入是什么，我们需要以下文件的内容:

models.py

tables.py

filters.py

form_helpers.py

forms.py

或者你可以尝试自己调试:

只需在您的项目中启动一个 python 解释器

import sare.urls或 import sare.views

它应该给出一个 ImportError，一个关于循环导入在哪里的更精确的线索