#32007: AttributeError: 'WhereNode' object has no attribute 'copy'
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Reporter: Gordon Wrigley | Owner: nobody
Type: Uncategorized | Status: new
Component: Uncategorized | Version: 3.1
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
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I think I've found a regression in 3.1, I'm seeing this across databases
and Python versions but only on Django 3.1.
With reference to the polls app the queryset I hit this on is essentially:
{{{#!python
Question.objects.values("question_text").annotate(
pub_date__count=Count("pub_date", distinct=True),
pub_date__is_null=ExpressionWrapper(Q(pub_date=None),
output_field=BooleanField())
).values("question_text", "pub_date__count", "pub_date__is_null")
}}}
This results in:
{{{
~\.venv\django_tutorial\lib\site-packages\django\db\models\query.py in
annotate(self, *args, **kwargs)
1121 clone.query.group_by = True
1122 else:
-> 1123 clone.query.set_group_by()
1124 break
1125
~\.venv\django_tutorial\lib\site-packages\django\db\models\sql\query.py in
set_group_by(self, allow_aliases)
1979 if not allow_aliases or alias in column_names:
1980 alias = None
-> 1981 group_by_cols =
annotation.get_group_by_cols(alias=alias)
1982 group_by.extend(group_by_cols)
1983 self.group_by = tuple(group_by)
~\.venv\django_tutorial\lib\site-packages\django\db\models\expressions.py
in get_group_by_cols(self, alias)
867
868 def get_group_by_cols(self, alias=None):
--> 869 expression = self.expression.copy()
870 expression.output_field = self.output_field
871 return expression.get_group_by_cols(alias=alias)
AttributeError: 'WhereNode' object has no attribute 'copy'
}}}
It's a bit of a dumb query but given my usecase https://pypi.org/project
/django-data-browser/ that's a little beyond my control.
Still it's kinda surprising that it worked on 3.0 and doesn't on 3.1.
It can be simplified a bit and still get essentially the same result:
{{{#!python
Question.objects.annotate(
pub_date__count=Count("pub_date", distinct=True),
pub_date__is_null=ExpressionWrapper(Q(pub_date=None),
output_field=BooleanField())
)
}}}
Removing either of the annotate clauses "fixes" it.
--
Ticket URL: <https://code.djangoproject.com/ticket/32007>
Django <https://code.djangoproject.com/>
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