From 720de4d0441fcfdb543051389c70efbe66ed962a Mon Sep 17 00:00:00 2001
From: Simon Charette <charette.s@gmail.com>
Date: Sat, 21 Dec 2019 23:22:49 -0500
Subject: [PATCH] Fixed #31109 -- Disabled grouping by aliases on
QuerySet.exists().
Clearing the SELECT clause in Query.has_results was orphaning GROUP BY
references to it.
Thanks Thierry Bastian for the report and Baptiste Mispelon for the
bisect.
Regression in fb3f034f1c63160c0ff13c609acd01c18be12f80.
---
django/db/models/sql/query.py | 8 ++++++--
docs/releases/3.0.2.txt | 3 +++
tests/aggregation/tests.py | 10 ++++++++++
3 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py
index ac4822e18a..fc423b6acf 100644
--- a/django/db/models/sql/query.py
+++ b/django/db/models/sql/query.py
@@ -526,7 +526,9 @@ class Query(BaseExpression):
if not q.distinct:
if q.group_by is True:
q.add_fields((f.attname for f in self.model._meta.concrete_fields), False)
- q.set_group_by()
+ # Disable GROUP BY aliases to avoid orphaning references to the
+ # SELECT clause which is about to be cleared.
+ q.set_group_by(allow_aliases=False)
q.clear_select_clause()
q.clear_ordering(True)
q.set_limits(high=1)
@@ -1916,7 +1918,7 @@ class Query(BaseExpression):
if force_empty:
self.default_ordering = False
- def set_group_by(self):
+ def set_group_by(self, allow_aliases=True):
"""
Expand the GROUP BY clause required by the query.
@@ -1938,6 +1940,8 @@ class Query(BaseExpression):
warnings.warn(msg, category=RemovedInDjango40Warning)
group_by_cols = annotation.get_group_by_cols()
else:
+ if not allow_aliases:
+ alias = None
group_by_cols = annotation.get_group_by_cols(alias=alias)
group_by.extend(group_by_cols)
self.group_by = tuple(group_by)
diff --git a/docs/releases/3.0.2.txt b/docs/releases/3.0.2.txt
index 53b066838a..ccc82b18ae 100644
--- a/docs/releases/3.0.2.txt
+++ b/docs/releases/3.0.2.txt
@@ -11,3 +11,6 @@ Bugfixes
* Fixed a regression in Django 3.0 that didn't include columns referenced by a
``Subquery()`` in the ``GROUP BY`` clause (:ticket:`31094`).
+
+* Fixed a regression in Django 3.0 where ``QuerySet.exists()`` crashed if a
+ queryset contained an aggregation over a ``Subquery()`` (:ticket:`31109`).
diff --git a/tests/aggregation/tests.py b/tests/aggregation/tests.py
index ecbe81c151..dd30f57bed 100644
--- a/tests/aggregation/tests.py
+++ b/tests/aggregation/tests.py
@@ -1141,6 +1141,16 @@ class AggregateTestCase(TestCase):
# The GROUP BY should not be by alias either.
self.assertEqual(ctx[0]['sql'].lower().count('latest_book_pubdate'), 1)
+ def test_aggregation_subquery_annotation_exists(self):
+ latest_book_pubdate_qs = Book.objects.filter(
+ publisher=OuterRef('pk')
+ ).order_by('-pubdate').values('pubdate')[:1]
+ publisher_qs = Publisher.objects.annotate(
+ latest_book_pubdate=Subquery(latest_book_pubdate_qs),
+ count=Count('book'),
+ )
+ self.assertTrue(publisher_qs.exists())
+
@skipUnlessDBFeature('supports_subqueries_in_group_by')
def test_group_by_subquery_annotation(self):
"""