[4.2.x] Fixed #34798 -- Fixed QuerySet.aggregate() crash when referencing expressions containing subqueries.

Regression in 59bea9efd2,
complements e5c844d6f2.

Refs #28477, #34551.

Thanks Haldun Komsuoglu for the report.

Backport of 3b4a571275 from main

django/db/models/expressions.py

@@ -255,6 +255,13 @@ class BaseExpression:
             for expr in self.get_source_expressions()
         )
 
+    @cached_property
+    def contains_subquery(self):
+        return any(
+            expr and (getattr(expr, "subquery", False) or expr.contains_subquery)
+            for expr in self.get_source_expressions()
+        )
+
     def resolve_expression(
         self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False
     ):

django/db/models/sql/query.py

@@ -404,7 +404,7 @@ class Query(BaseExpression):
             # members of `aggregates` to resolve against each others.
             self.append_annotation_mask([alias])
             refs_subquery |= any(
-                getattr(self.annotations[ref], "subquery", False)
+                getattr(self.annotations[ref], "contains_subquery", False)
                 for ref in aggregate.get_refs()
             )
             refs_window |= any(

docs/releases/4.2.7.txt

@@ -9,4 +9,6 @@ Django 4.2.7 fixes several bugs in 4.2.6.
 Bugfixes
 ========
 
-...
+* Fixed a regression in Django 4.2 that caused a crash of
+  ``QuerySet.aggregate()`` with aggregates referencing expressions containing
+  subqueries (:ticket:`34798`).

tests/aggregation/tests.py

@@ -2260,6 +2260,27 @@ class AggregateAnnotationPruningTests(TestCase):
         self.assertEqual(sql.count("select"), 3, "Subquery wrapping required")
         self.assertEqual(aggregate, {"sum_total_books": 3})
 
+    def test_referenced_composed_subquery_requires_wrapping(self):
+        total_books_qs = (
+            Author.book_set.through.objects.values("author")
+            .filter(author=OuterRef("pk"))
+            .annotate(total=Count("book"))
+        )
+        with self.assertNumQueries(1) as ctx:
+            aggregate = (
+                Author.objects.annotate(
+                    total_books=Subquery(total_books_qs.values("total")),
+                    total_books_ref=F("total_books") / 1,
+                )
+                .values("pk", "total_books_ref")
+                .aggregate(
+                    sum_total_books=Sum("total_books_ref"),
+                )
+            )
+        sql = ctx.captured_queries[0]["sql"].lower()
+        self.assertEqual(sql.count("select"), 3, "Subquery wrapping required")
+        self.assertEqual(aggregate, {"sum_total_books": 3})
+
     @skipUnlessDBFeature("supports_over_clause")
     def test_referenced_window_requires_wrapping(self):
         total_books_qs = Book.objects.annotate(