Nonetype object has no attribute 'model'

I have been trying to get a blogging system running on GAE. I am not familiar with GAE or BigTable (although I am comfortable using Django) so please bare with me.

I followed the instructions here (and have my app running):

http://djangoappengine.readthedocs.org/en/latest/

However, when I try to use the 'ArchiveIndexView' class based generic view the app throws an exception (Nonetype object has no attribute 'model'). Having dug about a bit I notice the following:

the 'get_selected_fields' method in 'basecompiler.py' is called twice per http request;
the first time it is called, query.select_fields == [];
the second time it is called, query.select_fields == [None]

This seems to be the route of the problem. I was wondering if this is a known issue, or if I have missed something along the way.

The View:

class ListingView(ArchiveIndexView):

    model = Post

    date_field = "created_date"

    date_type = 'year'

    allow_future = False

The Model:

class Post(models.Model):

    # Post title
    title = models.CharField(max_length=250)

    # Url safe title for the post
    url_safe_title = models.SlugField(max_length=250)

    # Post content 
    content = models.TextField()

    # Post created date 
    created_date = models.DateTimeField(auto_now_add=True)

    # Post updated date
    updated_date = models.DateTimeField(auto_now=True)

    # Store a reference to the user
    author = models.ForeignKey(User)

    # Method for getting an absolute url for the resource
    def get_absolute_url(self, *args, **kwargs):
        return reverse('admin-post-update', args=[self.id,])

    # Method for getting a delete url for the resource
    def get_delete_url(self, *args, **kwargs):
        return ""

    # Method for getting a listing url for our resources
    @staticmethod
    def get_listing_url():
        return reverse('admin-post-list')

    # Convenience method for generating
    # a friendly unicode representation
    # of the instance 
    def __unicode__(self):
        return self.title

Also, please find the application stacktrace below:

ERROR 2014-01-27 12:20:04,084 base.py:212] Internal Server Error: /blog/ Traceback (most recent call last): File "/Users/danielstringer/Dev/AppEngine/blog/django/core/handlers/base.py", line 115, in get_response response = callback(request, _callback_args, _callback_kwargs) File "/Users/danielstringer/Dev/AppEngine/blog/django/views/generic/base.py", line 68, in view return self.dispatch(request, _args, _kwargs) File "/Users/danielstringer/Dev/AppEngine/blog/django/views/generic/base.py", line 86, in dispatch return handler(request, _args, *_kwargs) File "/Users/danielstringer/Dev/AppEngine/blog/django/views/generic/dates.py", line 333, in get self.date_list, self.object_list, extra_context = self.get_dated_items() File "/Users/danielstringer/Dev/AppEngine/blog/django/views/generic/dates.py", line 412, in get_dated_items date_list = self.get_date_list(qs, ordering='DESC') File "/Users/danielstringer/Dev/AppEngine/blog/django/views/generic/dates.py", line 391, in get_date_list if date_list is not None and not date_list and not allow_empty: File "/Users/danielstringer/Dev/AppEngine/blog/django/db/models/query.py", line 157, in nonzero return type(self).bool(self) File "/Users/danielstringer/Dev/AppEngine/blog/django/db/models/query.py", line 151, in bool next(iter(self)) File "/Users/danielstringer/Dev/AppEngine/blog/django/db/models/query.py", line 139, in _result_iter self._fill_cache() File "/Users/danielstringer/Dev/AppEngine/blog/django/db/models/query.py", line 941, in _fill_cache self._result_cache.append(next(self._iter)) File "/Users/danielstringer/Dev/AppEngine/blog/djangotoolbox/db/basecompiler.py", line 375, in results_iter fields = self.get_fields() File "/Users/danielstringer/Dev/AppEngine/blog/djangotoolbox/db/basecompiler.py", line 519, in get_fields if field.model._meta != query_model._meta: AttributeError: 'NoneType' object has no attribute 'model' INFO 2014-01-27 12:20:04,314 dev_appserver.py:3090] "GET /blog/ HTTP/1.1" 500 -

I would be more than happy to help diagnose and fix this issue (if the issue is in the djangotoolbox codebase). I am interested in your thoughts.

Many thanks, Dan

django-nonrel / djangotoolbox

Nonetype object has no attribute 'model' #50