Fixed #8279 -- Multiple many-to-many relations to "self" are now possible.

        return smart_unicode(data)

    def contribute_to_class(self, cls, name):

        # To support multiple relations to self, it's useful to have a non-None

        # related name on symmetrical relations for internal reasons. The

        # concept doesn't make a lot of sense externally ("you want me to

        # specify *what* on my non-reversible relation?!"), so we set it up

        # automatically. The funky name reduces the chance of an accidental

        # clash.

        if self.rel.symmetrical and self.rel.related_name is None:

            self.rel.related_name = "%s_rel_+" % name

        super(ManyToManyField, self).contribute_to_class(cls, name)

        # Add the descriptor for the m2m relation

        setattr(cls, self.name, ReverseManyRelatedObjectsDescriptor(self))

from django.db import models

# No related name is needed here, since symmetrical relations are not

# explicitly reversible.

class SelfRefer(models.Model):

    name = models.CharField(max_length=10)

    references = models.ManyToManyField('self')

    related = models.ManyToManyField('self')

    def __unicode__(self):

        return self.name

class Tag(models.Model):

    name = models.CharField(max_length=10)

    def __unicode__(self):

        return self.name

# A related_name is required on one of the ManyToManyField entries here because

# they are both addressable as reverse relations from Tag.

class Entry(models.Model):

    name = models.CharField(max_length=10)

    topics = models.ManyToManyField(Tag)

    related = models.ManyToManyField(Tag, related_name="similar")

    def __unicode__(self):

        return self.name

__test__ = {"regressions": """

# Multiple m2m references to the same model or a different model must be

# distinguished when accessing the relations through an instance attribute.

>>> s1 = SelfRefer.objects.create(name='s1')

>>> s2 = SelfRefer.objects.create(name='s2')

>>> s3 = SelfRefer.objects.create(name='s3')

>>> s1.references.add(s2)

>>> s1.related.add(s3)

>>> e1 = Entry.objects.create(name='e1')

>>> t1 = Tag.objects.create(name='t1')

>>> t2 = Tag.objects.create(name='t2')

>>> e1.topics.add(t1)

>>> e1.related.add(t2)

>>> s1.references.all()

[<SelfRefer: s2>]

>>> s1.related.all()

[<SelfRefer: s3>]

>>> e1.topics.all()

[<Tag: t1>]

>>> e1.related.all()

[<Tag: t2>]

"""

}