Fixed #36264 -- Excluded proxy neighbors of parents from deletion collection when keep_parents=True.

Signed-off-by: saJaeHyukc <wogur981208@gmail.com>

django/db/models/deletion.py

@@ -309,7 +309,10 @@ class Collector:
         protected_objects = defaultdict(list)
         for related in get_candidate_relations_to_delete(model._meta):
             # Preserve parent reverse relationships if keep_parents=True.
-            if keep_parents and related.model in model._meta.all_parents:
+            if (
+                keep_parents
+                and related.model._meta.concrete_model in model._meta.all_parents
+            ):
                 continue
             field = related.field
             on_delete = field.remote_field.on_delete

tests/delete/models.py

@@ -32,6 +32,11 @@ class RChild(R):
     pass
 
 
+class RProxy(R):
+    class Meta:
+        proxy = True
+
+
 class RChildChild(RChild):
     pass
 
@@ -179,7 +184,7 @@ class RelToBase(models.Model):
 
 
 class Origin(models.Model):
-    pass
+    r_proxy = models.ForeignKey("RProxy", models.CASCADE, null=True)
 
 
 class Referrer(models.Model):

tests/delete/tests.py

@@ -34,6 +34,7 @@ from .models import (
     RChild,
     RChildChild,
     Referrer,
+    RProxy,
     S,
     T,
     User,
@@ -675,6 +676,14 @@ class DeletionTests(TestCase):
                 )
                 signal.disconnect(receiver, sender=Referrer)
 
+    def test_keep_parents_does_not_delete_proxy_related(self):
+        r_child = RChild.objects.create()
+        r_proxy = RProxy.objects.get(pk=r_child.pk)
+        Origin.objects.create(r_proxy=r_proxy)
+        self.assertEqual(Origin.objects.count(), 1)
+        r_child.delete(keep_parents=True)
+        self.assertEqual(Origin.objects.count(), 1)
+
 
 class FastDeleteTests(TestCase):
     def test_fast_delete_all(self):