#31367: ImportError error while importing class from auth/mixin to auth/view
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Reporter: Mehmet İnce | Owner: nobody
Type: Cleanup/optimization | Status: new
Component: contrib.auth | Version: 3.0
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 1
UI/UX: 0 |
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While I was doing some tests about discussion related to the
[https://groups.google.com/forum/#!topic/django-developers/PUQQUHIxEXQ] ,
I've realized that it's not possible to import class from
django.contrib.auth.mixins to the django.contrib.auth.views .
**Reproduce**
Add following mixin to the auth/mixins.py
{{{
class LoginRequiredExemptMixin(object):
login_required_exempt = True
}}}
And import it at auth/views.py and use it on one of the CBV. For instance
LoginView.
{{{
from django.contrib.auth.mixins import LoginRequiredExemptMixin
class LoginView(SuccessURLAllowedHostsMixin, FormView,
LoginRequiredExemptMixin):
"""
Display the login form and handle the login action.
"""
}}}
In that case, you will be seeing following ImportError
{{{
File "/Users/xxx/PycharmProjects/django/django/contrib/auth/mixins.py",
line 4, in <module>
from django.contrib.auth.views import redirect_to_login
File "/Users/xxx/PycharmProjects/django/django/contrib/auth/views.py",
line 13, in <module>
from django.contrib.auth.mixins import LoginRequiredExemptMixin
ImportError: cannot import name 'LoginRequiredExemptMixin' from
'django.contrib.auth.mixins'
(/Users/mince/PycharmProjects/django/django/contrib/auth/mixins.py)
}}}
**How To Fix**
The reason of the error is mixins.py file have "django.contrib.auth.views
import redirect_to_login" on line 4. Since the redirect_to_login is only
used one place (handle_no_permission function) in mixin.py we can remove
the import from top of the file and call it right before usage of the
imported function. For example as follow.
{{{
def handle_no_permission(self):
if self.raise_exception or self.request.user.is_authenticated:
raise PermissionDenied(self.get_permission_denied_message())
from django.contrib.auth.views import redirect_to_login
return redirect_to_login(self.request.get_full_path(),
self.get_login_url(), self.get_redirect_field_name())
}}}
On the other hand, I think why we have **SuccessURLAllowedHostsMixin**
class in auth/views.py file even though it's been called Mixin was related
that import code in mixin.py too.
By doing this changes we can even move **SuccessURLAllowedHostsMixin**
class to the mixins.py file since it's only being used in auth/views.py.
That little changes gives us flexibility to import mixings in the feature.
--
Ticket URL: <https://code.djangoproject.com/ticket/31367>
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