#25520: Cascade delete of proxy model children fails with IntegrityErrors
-------------------------------+--------------------
Reporter: jmurty | Owner: nobody
Type: Uncategorized | Status: new
Component: Uncategorized | Version: master
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------+--------------------
When deleting a concrete model based on proxy models, Django's deletion
collector does not find M2M reverse relationships to proxy parents; it
only finds these relationships for concrete parent models.
This means that deleting a proxy-based model object with extant M2M
relationships targeting a proxy parent will fail with integrity errors if
you use a database like PostgreSQL that enforces foreign key constraints.
The target model instance cannot be deleted because the M2M FK
relationships are not also deleted at the same time, and would otherwise
remain pointing to a non-existent record.
This issue tends to affect users of django-polymorphic who rely more than
most on proxy models, and has been reported in this context in #23076
I have created a Pull Requests based on the current master branch that
adds unit tests demonstrating the issue when run against a database that
enforces foreign key constrains, such as PostgreSQL:
https://github.com/django/django/pull/5404
This issue also affects versions 1.7 and 1.8 and perhaps also earlier
versions, but likely has not been encountered broadly because the use case
that triggers it is somewhat unusual.
--
Ticket URL: <https://code.djangoproject.com/ticket/25520>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/049.14b43ffd5de25cb95b363301c493d5d5%40djangoproject.com.
For more options, visit https://groups.google.com/d/optout.
