[3.1.x] Fixed #31773 -- Fixed preserving output_field in ExpressionWrapper for combined expressions.

Thanks Thodoris Sotiropoulos for the report and Simon Charette for the
implementation idea.

Regression in df32fd42b84cc6dbba173201f244491b0d154a63.
Backport of 8a6df55f2dd5131282084a4edfd48f63fbf8c69a from master

1 files changed, 10 insertions, 2 deletions

diff --git a/tests/annotations/tests.py b/tests/annotations/tests.py
index 9f35074934..aa3682b86b 100644
--- a/tests/annotations/tests.py
+++ b/tests/annotations/tests.py
@@ -6,8 +6,8 @@ from django.core.exceptions import FieldDoesNotExist, FieldError
 from django.db import connection
 from django.db.models import (
     BooleanField, Case, CharField, Count, DateTimeField, Exists,
-    ExpressionWrapper, F, Func, IntegerField, Max, NullBooleanField, OuterRef,
-    Q, Subquery, Sum, Value, When,
+    ExpressionWrapper, F, FloatField, Func, IntegerField, Max,
+    NullBooleanField, OuterRef, Q, Subquery, Sum, Value, When,
 )
 from django.db.models.expressions import RawSQL
 from django.db.models.functions import Length, Lower
@@ -178,6 +178,14 @@ class NonAggregateAnnotationTestCase(TestCase):
         self.assertEqual(book.combined, 12)
         self.assertEqual(book.rating_count, 1)
 
+    def test_combined_f_expression_annotation_with_aggregation(self):
+        book = Book.objects.filter(isbn='159059725').annotate(
+            combined=ExpressionWrapper(F('price') * F('pages'), output_field=FloatField()),
+            rating_count=Count('rating'),
+        ).first()
+        self.assertEqual(book.combined, 13410.0)
+        self.assertEqual(book.rating_count, 1)
+
     def test_aggregate_over_annotation(self):
         agg = Author.objects.annotate(other_age=F('age')).aggregate(otherage_sum=Sum('other_age'))
         other_agg = Author.objects.aggregate(age_sum=Sum('age'))