Not concrete exception when urls module imports invalid modules.

[Petr Marhoun <petr.marhoun@…>]

This code is in django.core.urlresolvers:

    def _get_urlconf_module(self):
        try:
            return self._urlconf_module
        except AttributeError:
            try:
                self._urlconf_module = __import__(self.urlconf_name, {}, {}, [''])
            except Exception, e:
                # Either an invalid urlconf_name, such as "foo.bar.", or some
                # kind of problem during the actual import.
                raise ImproperlyConfigured, "Error while importing URLconf %r: %s" % (self.urlconf_name, e)
            return self._urlconf_module
    urlconf_module = property(_get_urlconf_module)

It was sufficient for configuration files (almost) without imports:

from django.conf.urls.defaults import *

urlpatterns = patterns('',
    (r'^articles/2003/$', 'news.views.special_case_2003'),
    (r'^articles/(\d{4})/$', 'news.views.year_archive'),
    (r'^articles/(\d{4})/(\d{2})/$', 'news.views.month_archive'),
    (r'^articles/(\d{4})/(\d{2})/(\d+)/$', 'news.views.article_detail'),
)

But now it is possible to use this file:

from django.conf.urls.defaults import *
from news import views

urlpatterns = patterns('',
    (r'^articles/2003/$', views.special_case_2003),
    (r'^articles/(\d{4})/$', views.year_archive),
    (r'^articles/(\d{4})/(\d{2})/$', views.month_archive),
    (r'^articles/(\d{4})/(\d{2})/(\d+)/$', views.article_detail),
)

This file imports views, views probably import models and there are many possibilities for syntax errors. It is very difficult to tell where the error is.

So I would like to propose to show original exception in the debug mode:

    def _get_urlconf_module(self):
        try:
            return self._urlconf_module
        except AttributeError:
            try:
                self._urlconf_module = __import__(self.urlconf_name, {}, {}, [''])
            except Exception, e:
                # Either an invalid urlconf_name, such as "foo.bar.", or some
                # kind of problem during the actual import.
                from django.conf import settings
                if settings.DEBUG:
                    raise
                else:
                    raise ImproperlyConfigured, "Error while importing URLconf %r: %s" % (self.urlconf_name, e)
            return self._urlconf_module
    urlconf_module = property(_get_urlconf_module)

[Bastian Kleineidam <calvin@…>]

How about using the new settings.DEBUG_PROPAGATE_EXCEPTIONS instead of settings.DEBUG?

[Petr Marhoun <petr.marhoun@…>]

Replying to Bastian Kleineidam <calvin@debian.org>:

How about using the new settings.DEBUG_PROPAGATE_EXCEPTIONS instead of settings.DEBUG?

No, DEBUG_PROPAGATE_EXCEPTIONS is used in a handler (django.core.handlers.base.BaseHandler) not to show nice debugging page. But I want to show this page - with the right exception.

Simply always keep the original exception

The last patch was working great but I think it's not necessary to change the exceptions to ImproperlyConfigured exceptions even when not debugging. This simply doesn't prevent anything. It's still an exception so there is no added danger. On a live site exceptions will not show anyway so no need to test for DEBUG simply import an be done with it ;)

I'm tagging this for 1.0 since it's a really trivial fix that will prevent a lot frustration.

Yeah, preview would have been great ;)

import should have been __import__

[mrts]

+1.

[James Bennett]

Since this is yet another case of a more general and highly debatable problem, I'm punting back to post-1.0. Please leave it there.

#7979 is a duplicate of this issue.

[John-Scott Atlakson]

FYI, there is an older ticket [6537] with a patch (the 08/12/08 patch above is identical to the patch on ticket [6537]).

I am not suggesting this patch is the most philosophically pure solution but it certainly allows for more productive debugging for those who can't wait.

While one more ticket might not turn the raindrops into a 'big flood', there is perhaps more interest in this particular case of exception swallowing being resolved than was previously apparent.

Closed #6537 as a duplicate. As john_scott writes it has the exact same patch I submitted and similar arguments.

[Karen Tracey <kmtracey@…>]

Moving back to 1.0 per this note from Jacob on django-dev: ​http://groups.google.com/group/django-developers/msg/08965e9852949ec8?hl=en

(Though he did not specifically OK this getting moved back, the last paragraph sounds like he agrees something needs to be done for 1.0 to fix this particular case. If that's being covered by some other ticket please point me to it.)

Also, #8596 looks like another user tripping over this behavior.

[Jacob]

(In [8664]) Fixed #7524: allow errors raised during import of a urlconf to bubble up.

[Jacob]

Milestone 1.0 deleted