關於Django Specifying a namespace in include() without providing an app_name

運行環境

PyCharm 2017.1
Django 2.0.1
python 3.6.1

在網頁項目中使用include()方法

• 項目目錄中同時存在app/urls.py和proj/urls.py
• 在proj/urls.py使用include方法

from django.urls import path,include
from app import urls as app_url
urlpatterns = [
    path('', include(app_url, namespace='common')),
]

• 在app/urls.py中對應url

from django.urls import path
from .views import index
urlpatterns = [
    path('',index,name='index'),
]

runserver發生錯誤

django.core.exceptions.ImproperlyConfigured: 
Specifying a namespace in include() without providing an app_name is not supported. 
Set the app_name attribute in the included module, 
or pass a 2-tuple containing the list of patterns and app_name instead.

意思爲：
在include方法裏面指定namespace卻不提供app_name是不允許的。
在包含的模塊裏設置app_name變量，或者在include方法裏面提供app_name參數。

解決方法

方法1：在proj/urls.py中修改

from django.urls import path,include
from app import urls as app_url
urlpatterns = [
    path('', include((common_url,'common'), namespace='common')),
]

方法2：在app/urls.py中修改

from django.urls import path
from .views import index
app_name='common'
urlpatterns = [
    path('',index,name='index'),
]