#29172 closed Bug (fixed)
Using Window in Subquery causes AttributeError
| Reported by: | Tomáš Ehrlich | Owned by: | nobody |
|---|---|---|---|
| Component: | Database layer (models, ORM) | Version: | 2.0 |
| Severity: | Normal | Keywords: | subquery window expression orm |
| 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
Using Window expression within Subquery causes an AttributeError: 'NoneType' object has no attribute ‘relabeled_clone'
Error is raised in relabeled_clone method,
https://github.com/django/django/blob/master/django/db/models/expressions.py#L319
which calls e.relabeled_clone method on every expression returned from get_source_expressions.
Window expression returns source_expression, partition_by, order_by and frame in get_source_expression:
https://github.com/django/django/blob/master/django/db/models/expressions.py#L1188
but all parameters except source_expression are optional and might be None. This leads to AttributeError.
Change History (5)
comment:1 by , 7 years ago
| Has patch: | set |
|---|
comment:2 by , 7 years ago
| Triage Stage: | Unreviewed → Accepted |
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comment:3 by , 7 years ago
| Triage Stage: | Accepted → Ready for checkin |
|---|
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This seems reasonable yes. Test case from PR should work:
subquery_qs = Employee.objects.annotate( highest=Window(FirstValue('id'), partition_by=F('department'), order_by=F('salary').desc()) ).values('highest') highest_salary = Employee.objects.filter(pk__in=subquery_qs)