[Django] #20378: Reverse join fails when GenericRelation is defined on an abstract model
Django
--------------------------------------+--------------------
Reporter: gwahl@… | Owner: nobody
Type: Bug | Status: new
Component: contrib.contenttypes | Version: master
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
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When you define a GenericRelation on an abstract model:
{{{#!python
class HasLinks(models.Model):
links = generic.GenericRelation(Link)
class Meta:
abstract = True
class HasLinkThing(HasLinks):
pass
}}}
You should still be able to query using the reverse join:
{{{#!python
HasLinkThing.objects.filter(links=whatever)
}}}
But it fails with when trying to calculate the join columns, because it's
trying to get the pk of the abstract, instead of concrete, model:
{{{
Traceback (most recent call last):
File
".tox/py27-dj16/src/django/tests/generic_relations_regress/tests.py", line
145, in test_abstract_reverse_join
self.assertQuerysetEqual(HasLinkThing.objects.filter(links=link), [
File ".tox/py27-dj16/src/django/django/db/models/manager.py", line 163,
in filter
return self.get_queryset().filter(*args, **kwargs)
File ".tox/py27-dj16/src/django/django/db/models/query.py", line 661, in
filter
return self._filter_or_exclude(False, *args, **kwargs)
File ".tox/py27-dj16/src/django/django/db/models/query.py", line 679, in
_filter_or_exclude
clone.query.add_q(Q(*args, **kwargs))
File ".tox/py27-dj16/src/django/django/db/models/sql/query.py", line
1200, in add_q
clause = self._add_q(where_part, used_aliases)
File ".tox/py27-dj16/src/django/django/db/models/sql/query.py", line
1236, in _add_q
current_negated=current_negated)
File ".tox/py27-dj16/src/django/django/db/models/sql/query.py", line
1102, in build_filter
allow_explicit_fk=True)
File ".tox/py27-dj16/src/django/django/db/models/sql/query.py", line
1365, in setup_joins
connection = alias, opts.db_table,
join.join_field.get_joining_columns()
File ".tox/py27-dj16/src/django/django/db/models/fields/related.py",
line 862, in get_joining_columns
return self.field.get_reverse_joining_columns()
File ".tox/py27-dj16/src/django/django/db/models/fields/related.py",
line 1009, in get_reverse_joining_columns
return self.get_joining_columns(reverse_join=True)
File ".tox/py27-dj16/src/django/django/contrib/contenttypes/generic.py",
line 199, in get_joining_columns
return super(GenericRelation, self).get_joining_columns(reverse_join)
File ".tox/py27-dj16/src/django/django/db/models/fields/related.py",
line 1005, in get_joining_columns
source = self.reverse_related_fields if reverse_join else
self.related_fields
File ".tox/py27-dj16/src/django/django/db/models/fields/related.py",
line 980, in reverse_related_fields
return [(rhs_field, lhs_field) for lhs_field, rhs_field in
self.related_fields]
File ".tox/py27-dj16/src/django/django/db/models/fields/related.py",
line 975, in related_fields
self._related_fields = self.resolve_related_fields()
File ".tox/py27-dj16/src/django/django/contrib/contenttypes/generic.py",
line 178, in resolve_related_fields
self.to_fields = [self.model._meta.pk.name]
AttributeError: 'NoneType' object has no attribute 'name'
}}}
I've written a failing test to demonstrate:
https://github.com/fusionbox/django/commit/03aa282467b. This test passes
in django 1.5.1, but fails on master, so I believe this is a regression
introduced by #19385.
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Ticket URL: <https://code.djangoproject.com/ticket/20378>
Django <https://code.djangoproject.com/>
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Django
Reporter: gwahl@… | Owner: akaariai
Type: Bug | Status: assigned
Component: contrib.contenttypes | Version: master
Severity: Release blocker | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by akaariai):
* status: new => assigned
* severity: Normal => Release blocker
* needs_better_patch: => 0
* needs_tests: => 0
* owner: nobody => akaariai
* needs_docs: => 0
* stage: Unreviewed => Accepted
Comment:
Seems like a release blocker. I will try to fix this as soon as possible,
but unfortunately I don't have time in the next two weeks. So, if anybody
else wants to try to fix this feel free to do so...
--
Ticket URL: <https://code.djangoproject.com/ticket/20378#comment:1>
Django
Reporter: gwahl@… | Owner: akaariai
Component: contrib.contenttypes | Version: master
Severity: Release blocker | Resolution: fixed
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by Anssi Kääriäinen <akaariai@…>):
* status: assigned => closed
* resolution: => fixed
Comment:
In [changeset:"c9a96075fa02b6d52bec748ffdfb413688a15774"]:
{{{
#!CommitTicketReference repository=""
revision="c9a96075fa02b6d52bec748ffdfb413688a15774"
Fixed #20378 -- regression in GenericRelation on abstract model
When a GenericRelation was defined on abstract model, queries on childs
of the abstract model didn't work. The problem was in the way fields and
in particular field.rel was copied from models to their children.
The regression was likely caused by #19385. Thanks to Gavin Wahl for
spotting the regression.
}}}
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Ticket URL: <https://code.djangoproject.com/ticket/20378#comment:2>