id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
35833	Annotation yielding an empty set causes entire QuerySet to become empty	Jacob Walls		"With a nullable JSONField in my model:

{{{
class TileModel(models.Model):
   provisionaledits = JSONField(null=True)
}}}

If I then annotate with a set-returning function (e.g. JSONB_ARRAY_ELEMENTS on postgres) that happens to return an empty set, the entire QuerySet is zeroed out.

{{{
In [1]: from django.db.models import Func, F

In [2]: from arches.app.models.models import TileModel

In [3]: class JsonbArrayElements(Func):
   ...:     arity = 1
   ...:     contains_subquery = True  # Django 5.2: set_returning = True
   ...:     function = ""JSONB_ARRAY_ELEMENTS""
   ...: 

In [4]: TileModel.objects.count()
Out[4]: 9

In [5]: TileModel.objects.annotate(empty_set=JsonbArrayElements(F(""provisionaledits"")))
Out[5]: <QuerySet []>
}}}

I distilled this from a more complicated failure. If it helps, here is a query that fails more helpfully when you actually have JSON in the queried field but still can't extract array elements because it's not an array:

{{{
In [14]: TileModel.objects.create(provisionaledits={})
Out[14]: <TileModel: TileModel object (6ee450f7-b516-4c61-b6e7-52e876b878fe)>

In [15]: TileModel.objects.annotate(no_longer_empty=JsonbArrayElements(F(""provisionaledits"")))
Out[15]: DataError: cannot extract elements from an object
}}}

I guess I would expect an error in both cases instead of an empty queryset in the former. At the very least, I would only expect the annotation to yield some sort of empty value, not for the whole queryset to silently become empty."	Bug	closed	Database layer (models, ORM)	5.1	Normal	invalid		Devin Cox Simon Charette	Unreviewed	0	0	0	0	0	0