#24525: AssertionError at `Query.change_aliases`
-------------------------------------+-------------------------------------
Reporter: coolRR | Owner: nobody
Type: Bug | Status: closed
Component: Database layer | Version: 1.7
(models, ORM) |
Severity: Normal | Resolution: needsinfo
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by kevmitch):
In Django 1.8, with the models
{{{
#!python
from django.db import models
class Year(models.Model):
date = models.DateField(auto_now_add=True)
class Student(models.Model):
year = models.ForeignKey('Year')
number = models.PositiveIntegerField()
courses = models.ManyToManyField('Course')
class Course(models.Model):
year = models.ForeignKey('Year')
department = models.CharField(max_length=4)
number = models.PositiveIntegerField()
}}}
the following
{{{
#!python
course_instance.student_set.all() &
year_instance.student_set.exclude(courses__in=[other_course_instance])
}}}
will raise
{{{
Traceback (most recent call last):
File
"/home/kevmitch/projects/apprentice/and_assertion_error/enrollment/tests.py",
line 24, in test_and
result = math101.student_set.all() &
year.student_set.exclude(courses__in=[anth100])
File
"/home/kevmitch/projects/apprentice/apprentice/env/local/lib/python2.7
/site-packages/django/db/models/query.py", line 211, in __and__
combined.query.combine(other.query, sql.AND)
File
"/home/kevmitch/projects/apprentice/apprentice/env/local/lib/python2.7
/site-packages/django/db/models/sql/query.py", line 556, in combine
w.relabel_aliases(change_map)
File
"/home/kevmitch/projects/apprentice/apprentice/env/local/lib/python2.7
/site-packages/django/db/models/sql/where.py", line 285, in
relabel_aliases
child.relabel_aliases(change_map)
File
"/home/kevmitch/projects/apprentice/apprentice/env/local/lib/python2.7
/site-packages/django/db/models/sql/where.py", line 287, in
relabel_aliases
self.children[pos] = child.relabeled_clone(change_map)
File
"/home/kevmitch/projects/apprentice/apprentice/env/local/lib/python2.7
/site-packages/django/db/models/lookups.py", line 185, in relabeled_clone
new.rhs = new.rhs.relabeled_clone(relabels)
File
"/home/kevmitch/projects/apprentice/apprentice/env/local/lib/python2.7
/site-packages/django/db/models/sql/query.py", line 329, in
relabeled_clone
clone.change_aliases(change_map)
File
"/home/kevmitch/projects/apprentice/apprentice/env/local/lib/python2.7
/site-packages/django/db/models/sql/query.py", line 787, in change_aliases
assert set(change_map.keys()).intersection(set(change_map.values()))
== set()
AssertionError
}}}
The tests of attached project demonstrates it in action.
Essential elements for reproduction:
* One of the querysets generated from related manager of the ManyToMany
target
* The other queryset is generated by exclude()ing on the ManyToManyField
from the related manager of a "versioning" ForeignKey model
--
Ticket URL: <https://code.djangoproject.com/ticket/24525#comment:11>
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