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
25027	two relations on the same model with same related_name break the model	karyon	nobody	"consider the following models:
{{{
class UserProfile(models.Model):
    pass

class Course(models.Model):
    participants = models.ManyToManyField(UserProfile, related_name='+')

class Document(models.Model):
    last_modified_user = models.ForeignKey(UserProfile, related_name='+')
}}}

and the following query:
{{{
>>> str(Course.objects.first().participants.all().query)
'SELECT ""testapp_userprofile"".""id"" FROM ""testapp_userprofile"" INNER JOIN ""testapp_document"" ON ( ""testapp_userprofile"".""id"" = ""testapp_document"".""last_modified_user_id"" ) WHERE ""testapp_document"".""id"" = 1'
}}}

the join doesn't make any sense to me. it makes both assertions in the following test fail:

{{{
def test_related_name(self):
    user = UserProfile.objects.create()
    course = Course.objects.create()
    course.participants = UserProfile.objects.all()
    self.assertEqual(course.participants.count(), 1)
    self.assertEqual(list(course.participants.all()), [user])
}}}


changing the related name in one of the models to something else fixes this.

if using a related name other than '+', the test still fails as before and the check command does not complain either, but at least makemigrations will spot the mistake."	Bug	closed	Database layer (models, ORM)	1.8	Normal	duplicate		karyon	Unreviewed	0	0	0	0	0	0