#18823: Clear with a M2M field with a through model
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Reporter: anonymous | Owner: nobody
Type: Bug | Status: new
Component: Database layer | Version: 1.4
(models, ORM) | Resolution:
Severity: Release blocker | Triage Stage: Accepted
Keywords: | Needs documentation: 0
Has patch: 1 | Patch needs improvement: 0
Needs tests: 0 | UI/UX: 0
Easy pickings: 0 |
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Changes (by russellm):
* severity: Normal => Release blocker
* stage: Unreviewed => Accepted
Comment:
Via django-developers -- this bug has the potential for inadvertant data
loss:
{{{
class Through(models.Model):
two = models.ForeignKey('Model2', to_field='spot')
one = models.ForeignKey('Model1')
class Model1(models.Model):
name = models.CharField(max_length=100)
class Model2(models.Model):
spot = models.IntegerField(unique=True)
ones = models.ManyToManyField(Model1, through=Through)
# Create objects and relations
m = Model1(name='test')
m2 = Model2(spot=2, pk=1)
m3 = Model2(spot=1, pk=2)
m.save()
m2.save()
m3.save()
Through(two=m2, one=m).save()
Through(two=m3, one=m).save()
# Both have ones
m2.ones.all()
m3.ones.all()
m2.ones.clear()
# Still has ones, didn't get deleted when it should have
m2.ones.all()
# This got deleted instead
m3.ones.all()
}}}
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Ticket URL: <https://code.djangoproject.com/ticket/18823#comment:3>
Django <https://code.djangoproject.com/>
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