incorrect sql query in many to many backwards relation using an intermediate table

[ido]

using the following models:

class Project(models.Model):
    name       = models.CharField(max_length = 30, primary_key = True)
    startDate  = models.DateField(auto_now_add = True)
    active     = models.BooleanField(default = True)

    def __unicode__(self):
        return self.name

class Tag(models.Model):
    id      = models.AutoField(primary_key = True)
    name    = models.CharField(max_length = 100)
    type    = models.CharField(max_length = 100)
    project = models.ForeignKey(Project)

    class Meta:
        unique_together = ('name', 'project')

    def __unicode__(self):
        return self.name

class Document(models.Model):
    text      = models.CharField(max_length=200)
    project   = models.ForeignKey(Project)
    tags      = models.ManyToManyField(Tag, through='Document2Tag')

    class Meta:
        unique_together = ("text", "project")

    def __unicode__(self):
        return unicode(self.id)

class Document2Tag(models.Model):
    document  = models.ForeignKey(Document)
    tag     = models.ForeignKey(Tag)
    user    = models.ForeignKey(User)

    def __unicode__(self):
        return u'(%s, %s, %s)' % (self.document.id, self.tag.name, self.user.username)

I've made the following query:

>>> from general.models import *
>>> from django.contrib.auth.models import User
>>> user1 = User.objects.get(username='user1')
>>> user2 = User.objects.get(username='user2')
>>> project = Project.objects.get(name='project1')
>>> Document.objects.all()
[<Document: 1>, <Document: 2>]
>>> Tag.objects.all()
[<Tag: tag1>, <Tag: tag2>]
>>> Document2Tag.objects.all()
[<Document2Tag: (1, tag2, user2)>, <Document2Tag: (1, tag1, user1)>]
>>> tag1 = Tag.objects.get(name='tag1')
>>> tag1.document_set.filter(document2tag__user=user1)
[<Document: 1>]
>>> tag1.document_set.filter(document2tag__user=user2)
[<Document: 1>]

as you can see in the above scenario, 'tag1' is incorrectly associated with 'document1' when querying about 'user2'

the expected result would be an empty list on the last query.

the sql query for reference:

>>> print tag1.document_set.filter(document2tag__user=user2).query
SELECT `general_document`.`id`, `general_document`.`text`, `general_document`.`project_id` 
FROM `general_document` 
INNER JOIN `general_document2tag` 
    ON (`general_document`.`id` = `general_document2tag`.`document_id`) 
INNER JOIN `general_document2tag` T4 
    ON (`general_document`.`id` = T4.`document_id`) 
WHERE (`general_document2tag`.`tag_id` = BINARY 1  AND T4.`user_id` = BINARY 3 )

(note the double inner join with general_document2tag)

[Malcolm Tredinnick]

This is just a bug (maybe; I haven't examined it to see what's going on yet, but the example looks simple enough to be suspicious). It doesn't require additional feature additions to fix, so it's not on the beta track.

[Malcolm Tredinnick]

Related to #8046, but probably not fixed by that commit -- I need to write a proper test case (a smaller example) first. Doing that now.

[Malcolm Tredinnick]

(In [8521]) Added a test to show that [8472] also fixed #8254.

[Jacob]

Milestone 1.0 deleted