#24381: Cache pickling exception in 1.8a1 with cross-table filter params
-------------------------------------+-------------------------------------
Reporter: marktranchant | Owner: nobody
Type: Bug | Status: new
Component: Core (Cache system) | Version: 1.8alpha1
Severity: Release blocker | Resolution:
Keywords: cache pickle empty | Triage Stage:
queryset | Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Description changed by marktranchant:
Old description:
> 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.
New description:
In 1.7.4 (and prior versions back to at least 2011), 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.objects.filter(id=0),
for example), it works.
--
--
Ticket URL: <https://code.djangoproject.com/ticket/24381#comment:4>
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