[5.2.x] Fixed #36432 -- Fixed a prefetch_related crash on related target subclass queryset.

Regression in 626d77e52a3f247358514bcf51c761283968099c.

Refs #36116.

Thanks Cornelis Poppema for the excellent report.

Backport of 08187c94ed02c45ad40a32244dedeaa7ac71ca87 from main.

2 files changed, 17 insertions, 0 deletions

diff --git a/tests/prefetch_related/models.py b/tests/prefetch_related/models.py
index 2f37cde1c8..888485e169 100644
--- a/tests/prefetch_related/models.py
+++ b/tests/prefetch_related/models.py
@@ -271,6 +271,10 @@ class Employee(models.Model):
         ordering = ["id"]
 
 
+class SelfDirectedEmployee(Employee):
+    pass
+
+
 # Ticket #19607
 
 
diff --git a/tests/prefetch_related/tests.py b/tests/prefetch_related/tests.py
index b3531cc36f..3c0b5f4505 100644
--- a/tests/prefetch_related/tests.py
+++ b/tests/prefetch_related/tests.py
@@ -39,6 +39,7 @@ from .models import (
     Qualification,
     Reader,
     Room,
+    SelfDirectedEmployee,
     TaggedItem,
     Teacher,
     WordEntry,
@@ -435,6 +436,18 @@ class PrefetchRelatedTests(TestDataMixin, TestCase):
             authors[1].active_favorite_authors, [self.author3, self.author4]
         )
 
+    def test_prefetch_queryset_child_class(self):
+        employee = SelfDirectedEmployee.objects.create(name="Foo")
+        employee.boss = employee
+        employee.save()
+        with self.assertNumQueries(2):
+            retrieved_employee = SelfDirectedEmployee.objects.prefetch_related(
+                Prefetch("boss", SelfDirectedEmployee.objects.all())
+            ).get()
+        with self.assertNumQueries(0):
+            self.assertEqual(retrieved_employee, employee)
+            self.assertEqual(retrieved_employee.boss, retrieved_employee)
+
 
 class RawQuerySetTests(TestDataMixin, TestCase):
     def test_basic(self):