From ac9bdcabe10fb7ac0c7e9ebcd879f5e34bee776f Mon Sep 17 00:00:00 2001
From: Chris Wesseling <chris@maykinmedia.nl>
Date: Thu, 20 Nov 2025 15:01:14 +0100
Subject: [5.2.x] Fixed #36748 -- Filtered non-standard placeholders from
 UNNEST queries.

Backport of 5834643f43a767fe19f2c6d10217b204e7584ec8 from main.
---
 django/db/backends/postgresql/compiler.py          |  5 +++++
 docs/releases/5.2.9.txt                            |  3 +++
 tests/postgres_tests/fields.py                     |  5 +++++
 .../migrations/0002_create_test_models.py          | 23 ++++++++++++++++++++++
 tests/postgres_tests/models.py                     |  5 +++++
 tests/postgres_tests/test_bulk_update.py           |  8 ++++++++
 6 files changed, 49 insertions(+)

diff --git a/django/db/backends/postgresql/compiler.py b/django/db/backends/postgresql/compiler.py
index 344773fb7a..dc2db148ae 100644
--- a/django/db/backends/postgresql/compiler.py
+++ b/django/db/backends/postgresql/compiler.py
@@ -36,6 +36,11 @@ class SQLInsertCompiler(BaseSQLInsertCompiler):
             # Lack of fields denote the usage of the DEFAULT keyword
             # for the insertion of empty rows.
             or any(field is None for field in fields)
+            # Field.get_placeholder takes value as an argument, so the
+            # resulting placeholder might be dependent on the value.
+            # in UNNEST requires a single placeholder to "fit all values" in
+            # the array.
+            or any(hasattr(field, "get_placeholder") for field in fields)
             # Fields that don't use standard internal types might not be
             # unnest'able (e.g. array and geometry types are known to be
             # problematic).
diff --git a/docs/releases/5.2.9.txt b/docs/releases/5.2.9.txt
index 0d726de640..588c278be5 100644
--- a/docs/releases/5.2.9.txt
+++ b/docs/releases/5.2.9.txt
@@ -13,3 +13,6 @@ Bugfixes
   ``django.utils.feedgenerator.Stylesheet.__str__()`` did not escape
   the ``url``, ``mimetype``, and ``media`` attributes, potentially leading
   to invalid XML markup (:ticket:`36733`).
+
+* Fixed a bug in Django 5.2 on PostgreSQL where ``bulk_create()`` did not apply
+  a field's custom query placeholders (:ticket:`36748`).
diff --git a/tests/postgres_tests/fields.py b/tests/postgres_tests/fields.py
index c5dddf197f..d099effdd5 100644
--- a/tests/postgres_tests/fields.py
+++ b/tests/postgres_tests/fields.py
@@ -57,3 +57,8 @@ except ImportError:
 class EnumField(models.CharField):
     def get_prep_value(self, value):
         return value.value if isinstance(value, enum.Enum) else value
+
+
+class OffByOneField(models.IntegerField):
+    def get_placeholder(self, value, compiler, connection):
+        return "(%s + 1)"
diff --git a/tests/postgres_tests/migrations/0002_create_test_models.py b/tests/postgres_tests/migrations/0002_create_test_models.py
index 31705ae21a..1aa900f07a 100644
--- a/tests/postgres_tests/migrations/0002_create_test_models.py
+++ b/tests/postgres_tests/migrations/0002_create_test_models.py
@@ -9,6 +9,7 @@ from ..fields import (
     EnumField,
     HStoreField,
     IntegerRangeField,
+    OffByOneField,
     SearchVectorField,
 )
 from ..models import TagField
@@ -570,4 +571,26 @@ class Migration(migrations.Migration):
                 "required_db_vendor": "postgresql",
             },
         ),
+        migrations.CreateModel(
+            name="OffByOneModel",
+            fields=[
+                (
+                    "id",
+                    models.BigAutoField(
+                        verbose_name="ID",
+                        serialize=False,
+                        auto_created=True,
+                        primary_key=True,
+                    ),
+                ),
+                (
+                    "one_off",
+                    OffByOneField(),
+                ),
+            ],
+            options={
+                "required_db_vendor": "postgresql",
+            },
+            bases=(models.Model,),
+        ),
     ]
diff --git a/tests/postgres_tests/models.py b/tests/postgres_tests/models.py
index 1563f6a35d..7c606a83a9 100644
--- a/tests/postgres_tests/models.py
+++ b/tests/postgres_tests/models.py
@@ -9,6 +9,7 @@ from .fields import (
     EnumField,
     HStoreField,
     IntegerRangeField,
+    OffByOneField,
     SearchVectorField,
 )
 
@@ -207,3 +208,7 @@ class HotelReservation(PostgreSQLModel):
     end = models.DateTimeField()
     cancelled = models.BooleanField(default=False)
     requirements = models.JSONField(blank=True, null=True)
+
+
+class OffByOneModel(PostgreSQLModel):
+    one_off = OffByOneField()
diff --git a/tests/postgres_tests/test_bulk_update.py b/tests/postgres_tests/test_bulk_update.py
index 85dfcedd09..f3e8ac8a40 100644
--- a/tests/postgres_tests/test_bulk_update.py
+++ b/tests/postgres_tests/test_bulk_update.py
@@ -6,6 +6,7 @@ from .models import (
     IntegerArrayModel,
     NestedIntegerArrayModel,
     NullableIntegerArrayModel,
+    OffByOneModel,
     OtherTypesArrayModel,
     RangesModel,
 )
@@ -44,3 +45,10 @@ class BulkSaveTests(PostgreSQLTestCase):
                 self.assertSequenceEqual(
                     Model.objects.filter(**{field: new}), instances
                 )
+
+    def test_bulk_create(self):
+        OffByOneModel.objects.bulk_create(OffByOneModel(one_off=0) for _ in range(20))
+
+        self.assertSequenceEqual(
+            [m.one_off for m in OffByOneModel.objects.all()], 20 * [1]
+        )
-- 
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