Support Q expressions that contain subquery expressions.

Co-authored-by: CelestialGuru <45701317+CelestialGuru@users.noreply.github.com>
Co-authored-by: Brian Kohan <bckohan@gmail.com>

Author: CelestialGuru

docs/changelog.rst

@@ -1,6 +1,10 @@
 Changelog
 =========
 
+v4.3.0 (202X-XX-XX)
+-------------------
+* Fixed `Support Q expressions that contain subquery expressions <https://github.com/jazzband/django-polymorphic/pull/572>`_
+
 v4.2.0 (2025-12-04)
 -------------------
 

src/polymorphic/query_translate.py

@@ -70,8 +70,8 @@ def tree_node_correct_field_specs(my_model, node):
                 )
                 if new_expr:
                     node.children[i] = new_expr
-            else:
-                # this Q object child is another Q object, recursively process this as well
+            elif isinstance(child, models.Q):
+                # this Q object child is another Q object, recursively process
                 tree_node_correct_field_specs(my_model, child)
 
     if isinstance(potential_q_object, models.Q):

src/polymorphic/tests/migrations/0001_initial.py

@@ -1,4 +1,4 @@
-# Generated by Django 4.2.26 on 2025-12-03 23:29
+# Generated by Django 4.2.26 on 2025-12-04 12:57
 
 from django.db import migrations, models
 import django.db.models.deletion
@@ -12,8 +12,8 @@ class Migration(migrations.Migration):
     initial = True
 
     dependencies = [
-        ('contenttypes', '0002_remove_content_type_name'),
         ('auth', '0012_alter_user_first_name_max_length'),
+        ('contenttypes', '0002_remove_content_type_name'),
     ]
 
     operations = [
@@ -1097,7 +1097,7 @@ class Migration(migrations.Migration):
             fields=[
                 ('inlinemodela_ptr', models.OneToOneField(auto_created=True, on_delete=django.db.models.deletion.CASCADE, parent_link=True, primary_key=True, serialize=False, to='tests.inlinemodela')),
                 ('field2', models.CharField(max_length=30)),
-                ('plain_a', models.ForeignKey(blank=True, default=None, null=True, on_delete=django.db.models.deletion.SET_NULL, to='tests.plaina')),
+                ('plain_a', models.ForeignKey(blank=True, default=None, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='inline_bs', to='tests.plaina')),
             ],
             options={
                 'abstract': False,

src/polymorphic/tests/models.py

@@ -452,7 +452,12 @@ class InlineModelB(InlineModelA):
     field2 = models.CharField(max_length=30)
 
     plain_a = models.ForeignKey(
-        PlainA, null=True, blank=True, default=None, on_delete=models.SET_NULL
+        PlainA,
+        null=True,
+        blank=True,
+        default=None,
+        on_delete=models.SET_NULL,
+        related_name="inline_bs",
     )
 
 

src/polymorphic/tests/test_orm.py

@@ -4,7 +4,7 @@
 
 from django.contrib.contenttypes.models import ContentType
 from django.db import models, connection
-from django.db.models import Case, Count, FilteredRelation, Q, Sum, When, F
+from django.db.models import Case, Count, FilteredRelation, Q, Sum, When, Exists, OuterRef
 from django.db.utils import IntegrityError, NotSupportedError
 from django.test import TransactionTestCase
 from django.test.utils import CaptureQueriesContext
@@ -25,6 +25,9 @@
     CustomPkInherit,
     Enhance_Base,
     Enhance_Inherit,
+    InlineParent,
+    InlineModelA,
+    InlineModelB,
     InitTestModelSubclass,
     Model2A,
     Model2B,
@@ -1422,3 +1425,76 @@ def test_transmogrify_with_init(self):
         assert pur.color == "blue"
         # issues/615 fixes following line:
         assert pur.home == "Duckburg"
+
+    def test_subqueries(self):
+        PlainA.objects.all().delete()
+        InlineParent.objects.all().delete()
+        InlineModelA.objects.all().delete()
+        InlineModelB.objects.all().delete()
+
+        pa1 = PlainA.objects.create(field1="plain1")
+        PlainA.objects.create(field1="plain2")
+
+        ip1 = InlineParent.objects.create(title="parent1")
+        ip2 = InlineParent.objects.create(title="parent2")
+
+        ima1 = InlineModelA.objects.create(parent=ip1, field1="ima1")
+        ima2 = InlineModelA.objects.create(parent=ip2, field1="ima2")
+        imb1 = InlineModelB.objects.create(parent=ip1, field1="imab1", field2="imb1", plain_a=pa1)
+        imb2 = InlineModelB.objects.create(parent=ip2, field1="imab2", field2="imb2")
+
+        results = InlineModelA.objects.filter(
+            Exists(PlainA.objects.filter(inline_bs=OuterRef("pk")))
+            | Exists(InlineParent.objects.filter(inline_children=OuterRef("pk")))
+        )
+
+        assert ima1 in results
+        assert ima2 in results
+        assert imb1 in results
+        assert imb2 in results
+
+        results = InlineModelA.objects.filter(
+            Exists(PlainA.objects.filter(inline_bs=OuterRef("pk"), field1="plain1"))
+            | Exists(InlineParent.objects.filter(inline_children=OuterRef("pk"), title="parent2"))
+        )
+
+        assert ima1 not in results
+        assert ima2 in results
+        assert imb1 in results
+        assert imb2 in results
+
+        results = InlineModelA.objects.filter(
+            Exists(PlainA.objects.filter(inline_bs=OuterRef("pk")))
+        )
+
+        assert ima1 not in results
+        assert ima2 not in results
+        assert imb1 in results
+        assert imb2 not in results
+
+        results = InlineModelA.objects.filter(
+            Exists(PlainA.objects.filter(inline_bs=OuterRef("pk"))), field1="imab1"
+        )
+
+        assert ima1 not in results
+        assert ima2 not in results
+        assert imb1 in results
+        assert imb2 not in results
+
+        results = InlineModelA.objects.filter(
+            Exists(PlainA.objects.filter(inline_bs=OuterRef("pk"))), InlineModelB___field2="imb2"
+        )
+
+        assert not results
+
+        results = InlineModelA.objects.filter(
+            ~Exists(PlainA.objects.filter(inline_bs=OuterRef("pk"))), InlineModelB___field2="imb2"
+        )
+
+        assert len(results) == 1
+        assert imb2 in results
+
+        PlainA.objects.all().delete()
+        InlineParent.objects.all().delete()
+        InlineModelA.objects.all().delete()
+        InlineModelB.objects.all().delete()