Defining __nonzero__ (or __len__) on model makes it impossible to use in GenericForeignKey

[anonymous]

django/contrib/contenttypes/generic.py:
GenericForeignKey.get_content_type:

def get_content_type(self, obj=None, id=None, using=None):

# Convenience function using get_model avoids a circular import when
# using this model
ContentType = get_model("contenttypes", "contenttype")
if obj:

return ContentType.objects.db_manager(obj._state.db).get_for_model(obj)

if obj: case does not execute for any object which has False boolean value.

[Ramiro Morales]

Duplicate of #13085.