[Django] #24753: Reverse FK conditions filter queryset when used in case statements in some cases
Django
cases
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Reporter: mdentremont | Owner: nobody
Type: Bug | Status: new
Component: Database layer (models, ORM) | Version: 1.8
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
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I'm running into some odd behaviour with the new conditional support added
in 1.8.
My use case is the following:
- Annotate a queryset with the count of reverse FKs, matching a condition
This works fine given a many-to-one relationship, however not with many-
to-one/none.
With the many-to-one/none, it appears an INNER JOIN is made, which removes
objects from my queryset which an empty reverse FK set.
To summarize:
Expected:
Annotate all objects with the a count of reverse FKs matching a condition
Actual:
Annotate only objects objects with 1 or more associated reverse FKs, with
a count of the reverse FKs matching a condition
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Ticket URL: <https://code.djangoproject.com/ticket/24753>
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Django
cases
Reporter: mdentremont | Owner: nobody
Type: Bug | Status: new
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by mdentremont):
* needs_better_patch: => 0
* needs_tests: => 0
* needs_docs: => 0
Comment:
I've added a unit test which demonstrates the issue here:
https://github.com/django/django/pull/4613
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Ticket URL: <https://code.djangoproject.com/ticket/24753#comment:1>
Django
cases
Reporter: mdentremont | Owner: nobody
Type: Bug | Status: new
(models, ORM) |
Severity: Normal | Resolution:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Comment (by akaariai):
I have a guess what could be happening here. The ORM generates joins as
INNER JOINs when using build_filter(). We should manually promote those
joins to OUTER JOINs afterwards. Can't work on this today, so I'll check
this tomorrow.
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Ticket URL: <https://code.djangoproject.com/ticket/24753#comment:2>
Django
cases
Reporter: mdentremont | Owner: nobody
Type: Bug | Status: new
(models, ORM) |
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by timgraham):
* severity: Normal => Release blocker
* stage: Unreviewed => Accepted
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Ticket URL: <https://code.djangoproject.com/ticket/24753#comment:3>
Django
cases
Reporter: mdentremont | Owner: nobody
Type: Bug | Status: new
(models, ORM) |
Severity: Release blocker | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Comment (by shaib):
See also #24766, similar problems with non-aggregating annotations.
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Ticket URL: <https://code.djangoproject.com/ticket/24753#comment:4>
Django
cases
Reporter: mdentremont | Owner: nobody
Type: Bug | Status: closed
Component: Database layer | Version: 1.8
(models, ORM) |
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by timgraham):
* status: new => closed
* resolution: => duplicate
Comment:
The proposed test is similar to the one added with the fix for #24766 and
now passes.
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Ticket URL: <https://code.djangoproject.com/ticket/24753#comment:5>