id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
25284	QuerySet.filter(related_id=queryset) no longer does implicit __in lookup	no	nobody	"Consider the following:
{{{#!python
Model.objects.filter(related_id = RelatedModel.objects.all())
}}}

In django 1.8, the resulting query contains ""related_id **IN** (SELECT id FROM ...)""
In django 1.9, the ""IN"" is changed to an ""="", which causes the query to break in MySql and Postgres.

Is this an intentional change? If so, it needs to be documented as a breaking/backwards in-compatible change.

Test case:
{{{#!python

class Egg(models.Model):
  class Meta:
    app_label = 'spam'
  value = models.IntegerField()

class Spam(models.Model):
  class Meta:
    app_label = 'spam'
  egg = models.ForeignKey(Egg)

class TestAssign(TestCase):
  def test_subquery(self):
    egg1 = Egg.objects.create(value=1)
    egg11 = Egg.objects.create(value=1)

    Spam.objects.create(egg=egg1)
    Spam.objects.create(egg=egg11)

    eggs1=Egg.objects.filter(value=1)
    q = Spam.objects.filter(egg__in=eggs1)
    self.assertEqual(2, len(list(q)))
		

}}}"	Cleanup/optimization	closed	Documentation	dev	Normal	fixed			Accepted	1	0	0	0	0	0