Opened 5 years ago

Closed 5 years ago

#28917 closed Cleanup/optimization (fixed)

Remove paginator's unordered queryset warning for a .none() queryset

Reported by: Jeremy Lainé Owned by: Tim Graham <timograham@…>
Component: Core (Other) Version: 2.0
Severity: Normal Keywords:
Cc: Triage Stage: Ready for checkin
Has patch: yes Needs documentation: no
Needs tests: no Patch needs improvement: no
Easy pickings: no UI/UX: no

Description (last modified by Tim Graham)

Paginator shows a warning if it receives an unordered queryset.

However, if also emits this warning if passed a queryset which is guaranteed to be empty, for instance Article.objects.none().

Working around this warning involves doing a bizarre Article.objects.none().order_by('id')

I believe there can be legitimate usecases for passing a .none() queryset to a paginator, for instance if a user's permissions are such that we restrict the objects they can view to the empty queryset.

Change History (7)

comment:1 Changed 5 years ago by Junji Wei

Owner: changed from nobody to Junji Wei
Status: new → assigned

comment:2 Changed 5 years ago by Tim Graham

Component: Generic views → Core (Other)
Description: modified (diff)
Summary: Paginator shows ordering warning on an empty .none() queryset → Remove paginator's unordered queryset warning for a .none() queryset
Triage Stage: Unreviewed → Accepted
Type: Bug → Cleanup/optimization

comment:4 Changed 5 years ago by Sergey Fedoseev

Has patch: set

comment:5 Changed 5 years ago by Carlton Gibson

Patch needs improvement: set

Discussion on PR led to conclusion that this could be resolved by having QuerySet.ordered return True when the queryset is empty. (Something is ordered if it always returns the same sequence. An empty QuerySet does, i.e. [])

Marking as "Patch needs improvement" pending that change.

comment:6 Changed 5 years ago by Carlton Gibson

Owner: Junji Wei deleted
Patch needs improvement: unset
Status: assigned → new
Triage Stage: Accepted → Ready for checkin

​New PR from Josh Schneier.

Minor change to docstring suggested but otherwise, looks good.

comment:7 Changed 5 years ago by Tim Graham <timograham@…>

Owner: set to Tim Graham <timograham@…>
Resolution: → fixed
Status: new → closed

In 4d48ddd:

Fixed #28917 -- Prevented Paginator's unordered warning on EmptyQuerySet.

Thanks carltongibson for the idea and weijunji for the initial patch.

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