[Django] #25486: ORM generating incorrect query for through-model on .all()

[Django]

#25486: ORM generating incorrect query for through-model on 
<RelatedManager>.all()
----------------------------------------------+--------------------
     Reporter:  pembo13                       |      Owner:  nobody
         Type:  Bug                           |     Status:  new
    Component:  Database layer (models, ORM)  |    Version:  1.8
     Severity:  Normal                        |   Keywords:
 Triage Stage:  Unreviewed                    |  Has patch:  0
Easy pickings:  0                             |      UI/UX:  0
----------------------------------------------+--------------------
 I have a through-model which itself has a through model (because it needs
 a many-to-many relationship). The problem comes when i try to get related
 mode through this many-to-many relationship. The ORM generates the WHERE
 clause on the wrong field (the pk, instead of the fk).

 {{{
 #!sql
 -- generated sql
 SELECT "core_role"."id", "core_role"."name"
 FROM "core_role"
 INNER JOIN "core_dealercontactrole" ON ( "core_role"."id" =
 "core_dealercontactrole"."role_id" )
 WHERE "core_dealercontactrole"."id" = 8743
 ORDER BY "core_role"."name" ASC

 -- corrected sql
 SELECT "core_role"."id", "core_role"."name"
 FROM "core_role"
 INNER JOIN "core_dealercontactrole" ON ( "core_role"."id" =
 "core_dealercontactrole"."role_id" )
 WHERE "core_dealercontactrole"."dealercontact_id" = 8743
 ORDER BY "core_role"."name" ASC
 }}}

 The code that generated the query:

 {{{
 #!python
 dc = DealerContact.objects.get(id=8743)
 >>> unicode(dc.roles.all().query)
 u'SELECT "core_role"."id", "core_role"."name" FROM "core_role" INNER JOIN
 "core_dealercontactrole" ON ( "core_role"."id" =
 "core_dealercontactrole"."role_id" ) WHERE "core_dealercontactrole"."id" =
 8743 ORDER BY "core_role"."name" ASC'
 }}}

 Here are the models (with superfluous fields removed):

 {{{
 #!python
 class Contact(models.Model):

         first_name = models.CharField(blank=True, max_length=50)
         last_name = models.CharField(blank=True, max_length=50)

         class Meta:
                 ordering = ('last_name','first_name')

         pass

 class Dealer(models.Model):

         contacts = models.ManyToManyField('Contact',
 through='DealerContact', related_name='dealers')

         name = models.CharField(db_index=True, max_length=250)

         pass

 class DealerContact(models.Model):

         dealer = models.ForeignKey('Dealer',
 related_name='dealercontacts+', on_delete=models.CASCADE)
         contact = models.ForeignKey('Contact', related_name='+',
 on_delete=models.CASCADE)
         roles = models.ManyToManyField('Role',
 through='DealerContactRole', related_name='+')

         class Meta:
                 unique_together = ('dealer','contact')

         pass

 class DealerContactRole(models.Model):

         dealercontact = models.ForeignKey('DealerContact',
 related_name='+', on_delete=models.CASCADE)
         role = models.ForeignKey('Role', related_name='+')

         class Meta:
                 unique_together = ('dealercontact','role')

         pass

 class Role(models.Model):

         name = models.CharField(db_index=True, max_length=100)

         class Meta:
                 ordering = ('name',)

         pass
 }}}

--
Ticket URL: <https://code.djangoproject.com/ticket/25486>
Django <https://code.djangoproject.com/>
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