The crash is probably a bug: https://code.djangoproject.com/ticket/26261
On Friday, August 14, 2015 at 5:01:30 PM UTC-4, Daniel H wrote:
>
> Hi everyone.
>
> I've been using django for almost a year now, but it's my first time
> posting here.
>
> Anyway, I'm encountering an error which I think might be a bug. I've yet
> to try and replicate it as I thought posting here would be the better first
> step, as I might just be doing something incorrectly.
>
> When I try a query with .exclude() on a table with a GenericForeignKey and
> a reverse Generic Relation on a different table, I get this:
>
> AttributeError at /list
>
> 'GenericRelation' object has no attribute 'field'
>
>
> Here is a mock up of my database structure:
>
> class InternalOffer(models.Model):
> user = models.ForeignKey('User')
> status = models.CharField(max_length=64)
> (more offer data...)
> relation = GenericRelation(OfferJoin, related_query_name='offerquery')
>
> class ExternalOffer(models.Model):
> user = models.ForeignKey('User')
> status = models.CharField(max_length=64)
> (more offer data...)
> relation = GenericRelation(OfferJoin, related_query_name='offerquery')
>
> class OfferJoin(models.Model):
> content_type = models.ForeignKey(ContentType)
> object_id = models.PositiveIntegerField()
> offer = GenericForeignKey('content_type', 'object_id')
>
> I can filter fine, it's only the exclude that causes errors. Here is the
> code that causes the error:
>
> offers = OfferCover.objects.filter(offerquery__user__id=request.user.id)
> offers = offers.exclude(offerquery__status="Completed")
>
> Here's the full callback:
>
> Django Version: 1.8.2
> Python Version: 2.7.6
>
> Traceback:
> File "/Library/Python/2.7/site-packages/django/core/handlers/base.py" in
> get_response
> 132. response = wrapped_callback(request,
> *callback_args, **callback_kwargs)
> File "/Library/Python/2.7/site-packages/django/contrib/auth/decorators.py"
> in _wrapped_view
> 22. return view_func(request, *args, **kwargs)
> File "/Users/path-to-project/project/views.py" in list
> 136. offers = offers.exclude(o__status="Completed")
> File "/Library/Python/2.7/site-packages/django/db/models/query.py" in
> exclude
> 686. return self._filter_or_exclude(True, *args, **kwargs)
> File "/Library/Python/2.7/site-packages/django/db/models/query.py" in
> _filter_or_exclude
> 695. clone.query.add_q(~Q(*args, **kwargs))
> File "/Library/Python/2.7/site-packages/django/db/models/sql/query.py" in
> add_q
> 1304. clause, require_inner = self._add_q(where_part,
> self.used_aliases)
> File "/Library/Python/2.7/site-packages/django/db/models/sql/query.py" in
> _add_q
> 1332. allow_joins=allow_joins, split_subq=split_subq,
> File "/Library/Python/2.7/site-packages/django/db/models/sql/query.py" in
> build_filter
> 1180. can_reuse, e.names_with_path)
> File "/Library/Python/2.7/site-packages/django/db/models/sql/query.py" in
> split_exclude
> 1562. trimmed_prefix, contains_louter =
> query.trim_start(names_with_path)
> File "/Library/Python/2.7/site-packages/django/db/models/sql/query.py" in
> trim_start
> 1989. join_field = path.join_field.field
>
> Exception Type: AttributeError at /list
> Exception Value: 'GenericRelation' object has no attribute 'field'
>
> I've read the documentation multiple times and haven't come across
> anything usefull. I know that filtering GFKs alone won't work, but both
> filtering and excluding should work with the reverse Generic Relation.
>
> Thanks!
> - Daniel Harris
>
>
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