#29538 closed Bug (fixed)
Query Expression in ordering of a related object fails
Reported by: | wilhelmhb | Owned by: | Eduardo Rivas |
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Component: | Database layer (models, ORM) | Version: | 2.0 |
Severity: | Normal | Keywords: | ordering, query expression, related object |
Cc: | wilhelmhb, colons, Eduardo Rivas | 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 )
Since 2.0, according to the doc (https://docs.djangoproject.com/en/2.0/ref/models/options/#ordering), we can use QueryExpression objects in the Model.Meta.ordering field.
Using:
from django.db import models class Musician(models.Model): first_name = models.CharField(max_length=50) last_name = models.CharField(max_length=50) instrument = models.CharField(max_length=100, null=True, blank=True) class Meta: ordering = [models.F('instrument').asc(nulls_last=True)] class Album(models.Model): artist = models.ForeignKey(Musician, on_delete=models.CASCADE) name = models.CharField(max_length=100) release_date = models.DateField() num_stars = models.IntegerField() class Meta: ordering = ['artist']
>>> Album.objects.all() ... TypeError: 'OrderBy' does not support indexing
When reaching https://github.com/django/django/blob/master/django/db/models/sql/compiler.py#L669, the compiler tries to use the related model, but at line 679, item
can be an OrderBy object. Thus the failure.
Change History (17)
comment:1 by , 6 years ago
Cc: | added |
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comment:2 by , 6 years ago
Description: | modified (diff) |
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Summary: | QueryExpression in ordering of a related object fails → Query Expression in ordering of a related object fails |
Triage Stage: | Unreviewed → Accepted |
comment:3 by , 6 years ago
Owner: | changed from | to
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Status: | new → assigned |
comment:5 by , 6 years ago
Patch needs improvement: | set |
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comment:6 by , 6 years ago
Cc: | added |
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comment:7 by , 3 years ago
After 8c5f9906c56ac72fc4f13218dd90bdf9bc8a248b it crashes with:
django.core.exceptions.FieldError: Cannot resolve keyword 'instrument' into field. Choices are: artist, artist_id, id, name, num_stars, release_date
comment:9 by , 3 years ago
If anyone is interested in addressing this ticket there's a possible implementation detailed in https://code.djangoproject.com/ticket/33678#comment:3
comment:11 by , 3 years ago
Owner: | changed from | to
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comment:12 by , 3 years ago
Needs tests: | set |
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comment:13 by , 2 years ago
Needs tests: | unset |
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comment:14 by , 2 years ago
Triage Stage: | Accepted → Ready for checkin |
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follow-up: 17 comment:16 by , 20 months ago
Sorry for my ignorance, but is there a simple way for users to see, from this page, which minor versions of Django have received this patch? I followed the link to the github commit page, and from what I could tell there, the fix was implemented in 4.1. That doesn't tell me, however, if the commit was cherry-picked into any other branches.
At first I had assumed that since 3.2 was the latest LTS release, it would receive this fix. I upgraded to 3.2.18, though, and this bug isn't fixed. Looking closer at Django's docs, I see that 3.2 is only in extended support, and this bug does not qualify for extended support. Fair enough. I just think it would help developers to make it clear which of the current versions have received a given fix.
comment:17 by , 20 months ago
Replying to a-p-f:
Sorry for my ignorance, but is there a simple way for users to see, from this page, which minor versions of Django have received this patch? I followed the link to the github commit page, and from what I could tell there, the fix was implemented in 4.1. That doesn't tell me, however, if the commit was cherry-picked into any other branches.
At first I had assumed that since 3.2 was the latest LTS release, it would receive this fix. I upgraded to 3.2.18, though, and this bug isn't fixed. Looking closer at Django's docs, I see that 3.2 is only in extended support, and this bug does not qualify for extended support. Fair enough. I just think it would help developers to make it clear which of the current versions have received a given fix.
You can click commit (2798c937deb6625a4e6a36e70d4d60ce5faac954) which fixed this issue and check tags, 4.1a1
so it's fixed in Django 4.1+.
Started working on a fix.