[Django] #36408: PostgreSQL aggregates with order_by using OuterRef raise FieldError

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Django

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May 22, 2025, 6:47:44 AM5/22/25
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#36408: PostgreSQL aggregates with order_by using OuterRef raise FieldError
-------------------------------------+-------------------------------------
Reporter: Adam | Owner: Adam Johnson
Johnson |
Type: Bug | Status: assigned
Component: Database | Version: 5.2
layer (models, ORM) |
Severity: Release | Keywords:
blocker |
Triage Stage: | Has patch: 1
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
-------------------------------------+-------------------------------------
Like #36404, I have also encountered some `FieldError`s for a PostgreSQL
`ArrayAgg` that uses an `OuterRef` in its `order_by` clause.

For example, with models:

{{{#!python
from django.db import models


class Book(models.Model):
position = models.IntegerField()


class Chapter(models.Model):
book = models.ForeignKey(Book, on_delete=models.CASCADE)
}}}

And `QuerySet`:

{{{#!python
from django.contrib.postgres.aggregates import ArrayAgg
from django.db.models import OuterRef, Subquery

from example.models import Book, Chapter

Book.objects.annotate(
chapter_ids=Subquery(
Chapter.objects.annotate(
ids=ArrayAgg(
"id",
order_by=[OuterRef("position")],
)
).values("ids")[:1]
)
)
}}}

This error occurs:

{{{
$ python t.py
Traceback (most recent call last):
File "/.../t.py", line 15, in <module>
Chapter.objects.annotate(
~~~~~~~~~~~~~~~~~~~~~~~~^
ids=ArrayAgg(
^^^^^^^^^^^^^
...<2 lines>...
)
^
).values("ids")[:1]
^
File "/.../django/db/models/manager.py", line 87, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
File "/.../django/db/models/query.py", line 1647, in annotate
return self._annotate(args, kwargs, select=True)
~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/.../django/db/models/query.py", line 1699, in _annotate
clone.query.add_annotation(
~~~~~~~~~~~~~~~~~~~~~~~~~~^
annotation,
^^^^^^^^^^^
alias,
^^^^^^
select=select,
^^^^^^^^^^^^^^
)
^
File "/.../django/db/models/sql/query.py", line 1218, in
add_annotation
annotation = annotation.resolve_expression(self, allow_joins=True,
reuse=None)
File "/.../django/contrib/postgres/aggregates/mixins.py", line 33, in
resolve_expression
return super().resolve_expression(*args, **kwargs)
~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
File "/.../django/db/models/aggregates.py", line 63, in
resolve_expression
c = super().resolve_expression(query, allow_joins, reuse, summarize)
File "/.../django/db/models/expressions.py", line 300, in
resolve_expression
expr.resolve_expression(query, allow_joins, reuse, summarize)
~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/.../django/db/models/expressions.py", line 300, in
resolve_expression
expr.resolve_expression(query, allow_joins, reuse, summarize)
~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/.../django/db/models/expressions.py", line 941, in
resolve_expression
col = super().resolve_expression(*args, **kwargs)
File "/.../django/db/models/expressions.py", line 902, in
resolve_expression
return query.resolve_ref(self.name, allow_joins, reuse, summarize)
~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/.../django/db/models/sql/query.py", line 2049, in resolve_ref
join_info = self.setup_joins(
field_list, self.get_meta(), self.get_initial_alias(),
can_reuse=reuse
)
File "/.../django/db/models/sql/query.py", line 1900, in setup_joins
path, final_field, targets, rest = self.names_to_path(
~~~~~~~~~~~~~~~~~~^
names[:pivot],
^^^^^^^^^^^^^^
...<2 lines>...
fail_on_missing=True,
^^^^^^^^^^^^^^^^^^^^^
)
^
File "/.../django/db/models/sql/query.py", line 1805, in names_to_path
raise FieldError(
...<2 lines>...
)
django.core.exceptions.FieldError: Cannot resolve keyword 'position' into
field. Choices are: book, book_id, id
}}}

This error again bisects to e306687a3a5507d59365ba9bf545010e5fd4b2a8. The
cause is similar: duplicate `OuterRef` resolution occurs due to a clause
left in `OrderableAggMixin.resolve_expression()`.
--
Ticket URL: <https://code.djangoproject.com/ticket/36408>
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Django

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May 22, 2025, 6:49:35 AM5/22/25
to django-...@googlegroups.com
#36408: PostgreSQL aggregates with order_by using OuterRef raise FieldError
-------------------------------------+-------------------------------------
Reporter: Adam Johnson | Owner: Adam
| Johnson
Type: Bug | Status: assigned
Component: Database layer | Version: 5.2
(models, ORM) |
Severity: Release blocker | Resolution:
Keywords: | Triage Stage:
| Unreviewed
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Description changed by Adam Johnson:

Old description:
New description:

Like #36404, I have also encountered some `FieldError`s for a PostgreSQL
`ArrayAgg` that uses an `OuterRef` in its `order_by` clause.

The issue is reproduced ​in [https://github.com/adamchainz/django-
ticket-36408 this example project], with models:
--
Ticket URL: <https://code.djangoproject.com/ticket/36408#comment:1>

Django

unread,
May 22, 2025, 7:03:20 AM5/22/25
to django-...@googlegroups.com
#36408: PostgreSQL aggregates with order_by using OuterRef raise FieldError
-------------------------------------+-------------------------------------
Reporter: Adam Johnson | Owner: Adam
| Johnson
Type: Bug | Status: closed
Component: Database layer | Version: 5.2
(models, ORM) |
Severity: Release blocker | Resolution: duplicate
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Changes (by Adam Johnson):

* has_patch: 1 => 0
* resolution: => duplicate
* status: assigned => closed

Comment:

I just realized this is actually a duplicate of #36405:
`OrderableAggMixin.order_by` became `Aggregate.order_by` in #35444.

Updating that ticket with the description, and will update the existing PR
instead.
--
Ticket URL: <https://code.djangoproject.com/ticket/36408#comment:2>
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