#24752: Reusing a Case/Where object in a query causes a crash
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Reporter: mssnlayam | 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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Reusing a conditional expression `Case / When` that has already been used
causes a crash. Here is a simple example:
{{{#!python
import django
django.setup()
from django.contrib.auth.models import User
from django.db.models import When, Case, CharField, Value
SOME_CASE = Case(
When(pk=0, then=Value('0')),
default=Value('1'),
output_field=CharField(),
)
print User.objects.annotate(somecase=SOME_CASE)
print User.objects.annotate(somecase=SOME_CASE)
}}}
You can safely execute this program in your environment. The second
queryset crashes because it reuses the `SOME_CASE` object.
This probably related to #24420. This problem exists in both 1.8 and
1.8.1.
--
Ticket URL: <https://code.djangoproject.com/ticket/24752>
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