PostgresSQL ArrayField with size crashes with bulk_create

[Claude Paroz]

When trying to bulk_create model instances with an ArrayField with a specified size (and triggering the UNNEST instruction), the query crashes at database level (column "<field>" is of type double precision[] but expression is of type double precision).

Probably a regression in a16eedcf9c69d8a11d94cac1811018c5b996d491

A possible reproducing test:

diff --git a/tests/postgres_tests/migrations/0002_create_test_models.py b/tests/postgres_tests/migrations/0002_create_test_models.py
index 188f79607d..31705ae21a 100644
--- a/tests/postgres_tests/migrations/0002_create_test_models.py
+++ b/tests/postgres_tests/migrations/0002_create_test_models.py
@@ -167,6 +167,28 @@ class Migration(migrations.Migration):
             },
             bases=(models.Model,),
         ),
+        migrations.CreateModel(
+            name="WithSizeArrayModel",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        verbose_name="ID",
+                        serialize=False,
+                        auto_created=True,
+                        primary_key=True,
+                    ),
+                ),
+                (
+                    "field",
+                    ArrayField(models.FloatField(), size=2, null=True, blank=True),
+                ),
+            ],
+            options={
+                "required_db_vendor": "postgresql",
+            },
+            bases=(models.Model,),
+        ),
         migrations.CreateModel(
             name="NullableIntegerArrayModel",
             fields=[
diff --git a/tests/postgres_tests/models.py b/tests/postgres_tests/models.py
index e3118bc590..1563f6a35d 100644
--- a/tests/postgres_tests/models.py
+++ b/tests/postgres_tests/models.py
@@ -64,6 +64,10 @@ class DateTimeArrayModel(PostgreSQLModel):
     times = ArrayField(models.TimeField())
 
 
+class WithSizeArrayModel(PostgreSQLModel):
+    field = ArrayField(models.FloatField(), size=3)
+
+
 class NestedIntegerArrayModel(PostgreSQLModel):
     field = ArrayField(ArrayField(models.IntegerField()))
 
diff --git a/tests/postgres_tests/test_array.py b/tests/postgres_tests/test_array.py
index d930a01a1d..c2b0ebcd31 100644
--- a/tests/postgres_tests/test_array.py
+++ b/tests/postgres_tests/test_array.py
@@ -28,6 +28,7 @@ from .models import (
     OtherTypesArrayModel,
     PostgreSQLModel,
     Tag,
+    WithSizeArrayModel,
 )
 
 try:
@@ -216,6 +217,12 @@ class TestQuerying(PostgreSQLTestCase):
             ]
         )
 
+    def test_bulk_create_with_sized_arrayfield(self):
+        WithSizeArrayModel.objects.bulk_create([
+            WithSizeArrayModel(field=[1, 2]),
+            WithSizeArrayModel(field=[3, 4]),
+        ])
+
     def test_empty_list(self):
         NullableIntegerArrayModel.objects.create(field=[])
         obj = (

[Simon Charette]

Thanks Claude, I'll look at it shortly.

​The current heuristics to disable the optimization when dealing with ArrayField didn't account for sized ones.

[Sarah Boyce <42296566+sarahboyce@…>]

In 22fc151b:

Fixed #36107 -- Adjusted UNNEST bulk_create strategy to opt-out sized arrays.

The array fields opt-out heuristic failed to account for sized arrays.

Note that we keep relying on db_type as opposed to performing an ArrayField
instance check against the column's field as there could be other
implementations of model fields that use Postgres arrays to store the
optimization must be disabled for all of them.

Refs #35936.

Thanks Claude Paroz for the report and test.

[Sarah Boyce <42296566+sarahboyce@…>]

In ad6bca92:

[5.2.x] Fixed #36107 -- Adjusted UNNEST bulk_create strategy to opt-out sized arrays.

The array fields opt-out heuristic failed to account for sized arrays.

Note that we keep relying on db_type as opposed to performing an ArrayField
instance check against the column's field as there could be other
implementations of model fields that use Postgres arrays to store the
optimization must be disabled for all of them.

Refs #35936.

Thanks Claude Paroz for the report and test.

Backport of 22fc151bb86a553d84c62d7effd289356e9b6c6c from main.