From cc3870c30f0338a09e440430d5dcc028d23f1a02 Mon Sep 17 00:00:00 2001
From: Hannes Ljungberg <hannes.ljungberg@gmail.com>
Date: Mon, 9 Nov 2020 17:54:20 +0100
Subject: [PATCH] [3.1.x] Fixed #32182 -- Fixed crash of JSONField nested key
 transforms with subquery annotations on PostgreSQL.

Backport of 0773837e15bb632afffb6848a58c59a791008fa1 from master
---
 django/db/models/fields/json.py      |  3 ++-
 docs/releases/3.1.4.txt              |  3 +++
 tests/model_fields/test_jsonfield.py | 12 ++++++++++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/django/db/models/fields/json.py b/django/db/models/fields/json.py
index 5b0272a945..94596556d2 100644
--- a/django/db/models/fields/json.py
+++ b/django/db/models/fields/json.py
@@ -302,7 +302,8 @@ class KeyTransform(Transform):
     def as_postgresql(self, compiler, connection):
         lhs, params, key_transforms = self.preprocess_lhs(compiler, connection)
         if len(key_transforms) > 1:
-            return '(%s %s %%s)' % (lhs, self.postgres_nested_operator), params + [key_transforms]
+            sql = '(%s %s %%s)' % (lhs, self.postgres_nested_operator)
+            return sql, tuple(params) + (key_transforms,)
         try:
             lookup = int(self.key_name)
         except ValueError:
diff --git a/docs/releases/3.1.4.txt b/docs/releases/3.1.4.txt
index 6641b0aaf5..02408cca68 100644
--- a/docs/releases/3.1.4.txt
+++ b/docs/releases/3.1.4.txt
@@ -14,3 +14,6 @@ Bugfixes
 
 * Fixed passing extra HTTP headers to ``AsyncRequestFactory`` request methods
   (:ticket:`32159`).
+
+* Fixed crash of key transforms for :class:`~django.db.models.JSONField` on
+  PostgreSQL when using on a ``Subquery()`` annotation (:ticket:`32182`).
diff --git a/tests/model_fields/test_jsonfield.py b/tests/model_fields/test_jsonfield.py
index ea9bc2775b..b91d94752f 100644
--- a/tests/model_fields/test_jsonfield.py
+++ b/tests/model_fields/test_jsonfield.py
@@ -385,6 +385,18 @@ class TestQuerying(TestCase):
             [self.objs[4]],
         )
 
+    def test_nested_key_transform_on_subquery(self):
+        self.assertSequenceEqual(
+            NullableJSONModel.objects.filter(value__d__0__isnull=False).annotate(
+                subquery_value=Subquery(
+                    NullableJSONModel.objects.filter(pk=OuterRef('pk')).values('value')
+                ),
+                key=KeyTransform('d', 'subquery_value'),
+                chain=KeyTransform('f', KeyTransform('1', 'key')),
+            ).filter(chain='g'),
+            [self.objs[4]],
+        )
+
     def test_expression_wrapper_key_transform(self):
         self.assertSequenceEqual(
             NullableJSONModel.objects.annotate(