Generic Foreign Keys can't be used as lhs in lookups for historical
reasons. Django 1.6 gave a FieldDoesNotExist exception when using GFKs
as lhs in lookups, but due to regression caused by lookup refactor patch
(20bab2cf9d) the exception type was
changed to AttributeError.
It might be a good idea to add support for gfk__exact and gfk__in lookups
later on.
Thanks to glicerinu@gmail.com for the report. The code in this commit
was written by Tim Graham.
Backport of efe87d3e48 from master
GenericRelation now supports an optional related_query_name argument.
Setting related_query_name adds a relation from the related object back to
the content type for filtering, ordering and other query operations.
Thanks to Loic Bistuer for spotting a couple of important issues in
his review.
Allows a `GenericForeignKey` to reference proxy models. The default
for `for_concrete_model` is `True` to keep backwards compatibility.
Also added the analog `for_concrete_model` kwarg to
`generic_inlineformset_factory` to provide an API at the form level.
This also updates all dependent functionality, including modelform_factory
and modelformset_factory, and the generic views `ModelFormMixin`,
`CreateView` and `UpdateView` which gain a new `fields` attribute.