Opened 10 years ago

Last modified 10 years ago

#24381 closed Bug

Cache pickling exception in 1.8a1 with cross-table filter params — at Version 3

Reported by: Mark Tranchant Owned by: nobody
Component: Core (Cache system) Version: 1.8alpha1
Severity: Release blocker Keywords: cache pickle empty queryset
Cc: Triage Stage: Accepted
Has patch: yes Needs documentation: no
Needs tests: no Patch needs improvement: no
Easy pickings: no UI/UX: no

Description (last modified by Mark Tranchant)

In 1.7.4, I can run the following transcript in ../manage.py shell. The Contributor model has two ForeignKeys, to MyModel and Task, so I'm looking up all MyModels which have a referring contributor associated with task 4.

>>> from MyProject.models import *
>>> from django.core.cache import cache
>>> cl = MyModel.objects.filter(contributor__task__id=4)
>>> cl
<<< []
>>> type(cl)
<<< django.db.models.query.QuerySet
>>> cache.set('testing', cl)
>>> cache.get('testing')
<<< []

In 1.8a1, the cache set operation generates an exception. See attachment for trace.

PicklingError: Can't pickle <type 'module'>: it's not found as __builtin__.module

If I try to cache a simple empty QuerySet (MyModel.objecrts.filter(id=0), for example), it works.

Change History (4)

by Mark Tranchant, 10 years ago

Attachment: pickling-error.txt​ added

Exception trace

comment:1 by Mark Tranchant, 10 years ago

Summary: Cache pickling issue in 1.8a1 → Cache pickling exception in 1.8a1

comment:2 by Mark Tranchant, 10 years ago

Description: modified (diff)

comment:3 by Mark Tranchant, 10 years ago

Description: modified (diff)
Summary: Cache pickling exception in 1.8a1 → Cache pickling exception in 1.8a1 with cross-table filter params
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