#23467: Inconsistent behavior when filtering by inherited models when using a
proxy
model
-------------------------------------+-------------------------------------
Reporter: ajaest | Owner: nobody
Type: Bug | Status: new
Component: Database layer | Version: 1.6
(models, ORM) | Resolution:
Severity: Normal | Triage Stage:
Keywords: inherit, proxy, | Unreviewed
model, queryset, filter | Needs documentation: 0
Has patch: 0 | Patch needs improvement: 0
Needs tests: 0 | UI/UX: 0
Easy pickings: 0 |
-------------------------------------+-------------------------------------
Comment (by ajaest):
Maybe the problem is easy to fix. There you have a couple of examples I
was able to run after a small hack:
{{{
Python 2.7.5 (default, Jun 25 2014, 10:19:55)
[GCC 4.8.2 20131212 (Red Hat 4.8.2-7)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> ParentModel.objects.filter(childmodel=None)
[<ParentModel: ParentModel object>]
>>> ParentProxyModel.objects.filter(childmodel=None)
Traceback (most recent call last):
File "<console>", line 1, in <module>
File "/home/ajaest/Code/pfc/src/.env/lib/python2.7/site-
packages/django/db/models/manager.py", line 163, in filter
return self.get_queryset().filter(*args, **kwargs)
File "/home/ajaest/Code/pfc/src/.env/lib/python2.7/site-
packages/django/db/models/query.py", line 590, in filter
return self._filter_or_exclude(False, *args, **kwargs)
File "/home/ajaest/Code/pfc/src/.env/lib/python2.7/site-
packages/django/db/models/query.py", line 608, in _filter_or_exclude
clone.query.add_q(Q(*args, **kwargs))
File "/home/ajaest/Code/pfc/src/.env/lib/python2.7/site-
packages/django/db/models/sql/query.py", line 1198, in add_q
clause = self._add_q(where_part, used_aliases)
File "/home/ajaest/Code/pfc/src/.env/lib/python2.7/site-
packages/django/db/models/sql/query.py", line 1234, in _add_q
current_negated=current_negated)
File "/home/ajaest/Code/pfc/src/.env/lib/python2.7/site-
packages/django/db/models/sql/query.py", line 1100, in build_filter
allow_explicit_fk=True)
File "/home/ajaest/Code/pfc/src/.env/lib/python2.7/site-
packages/django/db/models/sql/query.py", line 1357, in setup_joins
names, opts, allow_many, allow_explicit_fk)
File "/home/ajaest/Code/pfc/src/.env/lib/python2.7/site-
packages/django/db/models/sql/query.py", line 1277, in names_to_path
"Choices are: %s" % (name, ", ".join(available)))
FieldError: Cannot resolve keyword 'childmodel' into field. Choices are:
id
>>> qs = ParentModel.objects.filter(childmodel=None)
>>> qs.model = ParentProxyModel
>>> qs
[<ParentProxyModel: ParentProxyModel object>]
>>>
}}}
{{{
Python 2.7.5 (default, Jun 25 2014, 10:19:55)
[GCC 4.8.2 20131212 (Red Hat 4.8.2-7)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>>
ParentModel.objects.annotate(childmodel_count=Count('childmodel')).values_list('childmodel')
[(None,), (2L,)]
>>>
ParentProxyModel.objects.annotate(childmodel_count=Count('childmodel')).values_list('childmodel')
Traceback (most recent call last):
File "<console>", line 1, in <module>
File "/home/ajaest/Code/pfc/src/.env/lib/python2.7/site-
packages/django/db/models/manager.py", line 169, in annotate
return self.get_queryset().annotate(*args, **kwargs)
File "/home/ajaest/Code/pfc/src/.env/lib/python2.7/site-
packages/django/db/models/query.py", line 714, in annotate
is_summary=False)
File "/home/ajaest/Code/pfc/src/.env/lib/python2.7/site-
packages/django/db/models/sql/query.py", line 985, in add_aggregate
field_list, opts, self.get_initial_alias())
File "/home/ajaest/Code/pfc/src/.env/lib/python2.7/site-
packages/django/db/models/sql/query.py", line 1357, in setup_joins
names, opts, allow_many, allow_explicit_fk)
File "/home/ajaest/Code/pfc/src/.env/lib/python2.7/site-
packages/django/db/models/sql/query.py", line 1277, in names_to_path
"Choices are: %s" % (name, ", ".join(available)))
FieldError: Cannot resolve keyword 'childmodel' into field. Choices are:
id
>>> qs =
ParentModel.objects.annotate(childmodel_count=Count('childmodel'))
>>> qs.model = ParentProxyModel
>>> qs.values_list('childmodel_count')
[(0,), (1,)]
>>>
}}}
Both examples work even if the database was not hit (and therefore the
cache not filled)
--
Ticket URL: <https://code.djangoproject.com/ticket/23467#comment:2>
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