Fix proxy model Query.remove_inherited_models()

Fixed #18248 -- proxy models were added to included_inherited_models
in sql.query.Query. The variable is meant to be used for multitable
inheritance only. This mistake caused problems in situations where
proxy model's query was reused.

2 files changed, 17 insertions, 1 deletions

diff --git a/tests/regressiontests/queries/models.py b/tests/regressiontests/queries/models.py
index 89eefdf48e..07aa6db67b 100644
--- a/tests/regressiontests/queries/models.py
+++ b/tests/regressiontests/queries/models.py
@@ -10,6 +10,10 @@ from django.db import models
 class DumbCategory(models.Model):
     pass
 
+class ProxyCategory(DumbCategory):
+    class Meta:
+        proxy = True
+
 class NamedCategory(DumbCategory):
     name = models.CharField(max_length=10)
 
diff --git a/tests/regressiontests/queries/tests.py b/tests/regressiontests/queries/tests.py
index 416970d493..8e86903724 100644
--- a/tests/regressiontests/queries/tests.py
+++ b/tests/regressiontests/queries/tests.py
@@ -19,7 +19,7 @@ from .models import (Annotation, Article, Author, Celebrity, Child, Cover,
     ManagedModel, Member, NamedCategory, Note, Number, Plaything, PointerA,
     Ranking, Related, Report, ReservedName, Tag, TvChef, Valid, X, Food, Eaten,
     Node, ObjectA, ObjectB, ObjectC, CategoryItem, SimpleCategory,
-    SpecialCategory, OneToOneCategory, NullableName)
+    SpecialCategory, OneToOneCategory, NullableName, ProxyCategory)
 
 
 class BaseQuerysetTest(TestCase):
@@ -1952,3 +1952,15 @@ class EmptyStringsAsNullTest(TestCase):
             DumbCategory.objects.exclude(namedcategory__name__in=['nonexisting']),
             [self.nc.pk], attrgetter('pk')
         )
+
+class ProxyQueryCleanupTest(TestCase):
+    def test_evaluated_proxy_count(self):
+        """
+        Test that generating the query string doesn't alter the query's state
+        in irreversible ways. Refs #18248.
+        """
+        ProxyCategory.objects.create()
+        qs = ProxyCategory.objects.all()
+        self.assertEqual(qs.count(), 1)
+        str(qs.query)
+        self.assertEqual(qs.count(), 1)