Fixed #25685 -- Fixed a duplicate query regression on deletion of proxied models.

Thanks to Trac alias ppetrid for the report and Tim for the review.

Conflicts:
	django/db/models/deletion.py
	tests/delete/tests.py

Forward port of 7c3ef19978b36b61db88a519f799f1ce8d019679 from stable/1.8.x

2 files changed, 17 insertions, 0 deletions

diff --git a/tests/delete/models.py b/tests/delete/models.py
index a7838c4510..60e7f5957c 100644
--- a/tests/delete/models.py
+++ b/tests/delete/models.py
@@ -99,6 +99,12 @@ class Avatar(models.Model):
     desc = models.TextField(null=True)
 
 
+# This model is used to test a duplicate query regression (#25685)
+class AvatarProxy(Avatar):
+    class Meta:
+        proxy = True
+
+
 class User(models.Model):
     avatar = models.ForeignKey(Avatar, models.CASCADE, null=True)
 
diff --git a/tests/delete/tests.py b/tests/delete/tests.py
index 9e383acb4e..663a22791b 100644
--- a/tests/delete/tests.py
+++ b/tests/delete/tests.py
@@ -414,6 +414,17 @@ class DeletionTests(TestCase):
         for k, v in existed_objs.items():
             self.assertEqual(deleted_objs[k], v)
 
+    def test_proxied_model_duplicate_queries(self):
+        """
+        #25685 - Deleting instances of a model with existing proxy
+        classes should not issue multiple queries during cascade
+        deletion of referring models.
+        """
+        avatar = Avatar.objects.create()
+        # One query for the Avatar table and a second for the User one.
+        with self.assertNumQueries(2):
+            avatar.delete()
+
 
 class FastDeleteTests(TestCase):