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
20564	Querying (exclude) on a GenericRelation's DateTimeField through a related object fails	Nicolas Ferrari	nobody	"While excluding directly on a GenericRelation's DateTimeField works (see c3 variable below), it does fail if there is a related object in between (c4). This does not occur if lookup is done on a CharField (c1 and c2).

Here are simple models to illustrate:


{{{
from django.db import models
from django.contrib.contenttypes import generic
from django.contrib.contenttypes.models import ContentType

class A(models.Model):

    name = models.CharField(max_length=""50"")
    flag = models.DateTimeField(null=True, blank=True)

    content_type = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    content_object = generic.GenericForeignKey('content_type', 'object_id')

    class Meta:
        app_label = 'foobar'

class B(models.Model):

    a = generic.GenericRelation(A)

    class Meta:
        app_label = 'foobar'

class C(models.Model):

    b = models.ForeignKey(B)
    a = generic.GenericRelation(A)

    class Meta:
        app_label = 'foobar'

# Works:
c1 = C.objects.exclude(a__name=""foo"")
c2 = C.objects.exclude(b__a__name=""foo"")
c3 = C.objects.exclude(a__flag=None)

# Fails:
c4 = C.objects.exclude(b__a__flag=None)

}}}

Find a workaround seems pretty tricky in some cases...

"	Bug	closed	Database layer (models, ORM)	1.6-alpha-1	Release blocker	fixed	contenttype exclude		Accepted	0	0	0	0	0	0