Refs #34233 -- Used types.NoneType.

Available since Python 3.10 where it was reintroduced.

django/contrib/gis/gdal/srs.py

@@ -28,6 +28,7 @@
 """
 from ctypes import byref, c_char_p, c_int
 from enum import IntEnum
+from types import NoneType
 
 from django.contrib.gis.gdal.base import GDALBase
 from django.contrib.gis.gdal.error import SRSException
@@ -57,7 +58,7 @@ class SpatialReference(GDALBase):
         EPSG code, a PROJ string, and/or a projection "well known" shorthand
         string (one of 'WGS84', 'WGS72', 'NAD27', 'NAD83').
         """
-        if not isinstance(axis_order, (type(None), AxisOrder)):
+        if not isinstance(axis_order, (NoneType, AxisOrder)):
             raise ValueError(
                 "SpatialReference.axis_order must be an AxisOrder instance."
             )

django/contrib/postgres/constraints.py

@@ -1,3 +1,5 @@
+from types import NoneType
+
 from django.contrib.postgres.indexes import OpClass
 from django.core.exceptions import ValidationError
 from django.db import DEFAULT_DB_ALIAS, NotSupportedError
@@ -45,13 +47,13 @@ class ExclusionConstraint(BaseConstraint):
             isinstance(expr, (list, tuple)) and len(expr) == 2 for expr in expressions
         ):
             raise ValueError("The expressions must be a list of 2-tuples.")
-        if not isinstance(condition, (type(None), Q)):
+        if not isinstance(condition, (NoneType, Q)):
             raise ValueError("ExclusionConstraint.condition must be a Q instance.")
-        if not isinstance(deferrable, (type(None), Deferrable)):
+        if not isinstance(deferrable, (NoneType, Deferrable)):
             raise ValueError(
                 "ExclusionConstraint.deferrable must be a Deferrable instance."
             )
-        if not isinstance(include, (type(None), list, tuple)):
+        if not isinstance(include, (NoneType, list, tuple)):
             raise ValueError("ExclusionConstraint.include must be a list or tuple.")
         self.expressions = expressions
         self.index_type = index_type or "GIST"

django/contrib/sites/checks.py

@@ -1,10 +1,12 @@
+from types import NoneType
+
 from django.conf import settings
 from django.core.checks import Error
 
 
 def check_site_id(app_configs, **kwargs):
     if hasattr(settings, "SITE_ID") and not isinstance(
-        settings.SITE_ID, (type(None), int)
+        settings.SITE_ID, (NoneType, int)
     ):
         return [
             Error("The SITE_ID setting must be an integer", id="sites.E101"),

django/db/migrations/serializer.py

@@ -304,7 +304,7 @@ class TypeSerializer(BaseSerializer):
     def serialize(self):
         special_cases = [
             (models.Model, "models.Model", ["from django.db import models"]),
-            (type(None), "type(None)", []),
+            (types.NoneType, "types.NoneType", ["import types"]),
         ]
         for case, string, imports in special_cases:
             if case is self.value:
@@ -338,7 +338,7 @@ class Serializer:
         (datetime.date, datetime.timedelta, datetime.time): DateTimeSerializer,
         SettingsReference: SettingsReferenceSerializer,
         float: FloatSerializer,
-        (bool, int, type(None), bytes, str, range): BaseSimpleSerializer,
+        (bool, int, types.NoneType, bytes, str, range): BaseSimpleSerializer,
         decimal.Decimal: DecimalSerializer,
         (functools.partial, functools.partialmethod): FunctoolsPartialSerializer,
         (

django/db/models/constraints.py

@@ -1,4 +1,5 @@
 from enum import Enum
+from types import NoneType
 
 from django.core.exceptions import FieldError, ValidationError
 from django.db import connections
@@ -148,7 +149,7 @@ class UniqueConstraint(BaseConstraint):
             raise ValueError(
                 "UniqueConstraint.fields and expressions are mutually exclusive."
             )
-        if not isinstance(condition, (type(None), Q)):
+        if not isinstance(condition, (NoneType, Q)):
             raise ValueError("UniqueConstraint.condition must be a Q instance.")
         if condition and deferrable:
             raise ValueError("UniqueConstraint with conditions cannot be deferred.")
@@ -163,11 +164,11 @@ class UniqueConstraint(BaseConstraint):
                 "UniqueConstraint.opclasses cannot be used with expressions. "
                 "Use django.contrib.postgres.indexes.OpClass() instead."
             )
-        if not isinstance(deferrable, (type(None), Deferrable)):
+        if not isinstance(deferrable, (NoneType, Deferrable)):
             raise ValueError(
                 "UniqueConstraint.deferrable must be a Deferrable instance."
             )
-        if not isinstance(include, (type(None), list, tuple)):
+        if not isinstance(include, (NoneType, list, tuple)):
             raise ValueError("UniqueConstraint.include must be a list or tuple.")
         if not isinstance(opclasses, (list, tuple)):
             raise ValueError("UniqueConstraint.opclasses must be a list or tuple.")

django/db/models/expressions.py

@@ -4,6 +4,7 @@ import functools
 import inspect
 from collections import defaultdict
 from decimal import Decimal
+from types import NoneType
 from uuid import UUID
 
 from django.core.exceptions import EmptyResultSet, FieldError, FullResultSet
@@ -506,7 +507,6 @@ class Expression(BaseExpression, Combinable):
 # The current approach for NULL is based on lowest common denominator behavior
 # i.e. if one of the supported databases is raising an error (rather than
 # return NULL) for `val <op> NULL`, then Django raises FieldError.
-NoneType = type(None)
 
 _connector_combinations = [
     # Numeric operations - operands of same type.

django/db/models/indexes.py

@@ -1,3 +1,5 @@
+from types import NoneType
+
 from django.db.backends.utils import names_digest, split_identifier
 from django.db.models.expressions import Col, ExpressionList, F, Func, OrderBy
 from django.db.models.functions import Collate
@@ -26,7 +28,7 @@ class Index:
     ):
         if opclasses and not name:
             raise ValueError("An index must be named to use opclasses.")
-        if not isinstance(condition, (type(None), Q)):
+        if not isinstance(condition, (NoneType, Q)):
             raise ValueError("Index.condition must be a Q instance.")
         if condition and not name:
             raise ValueError("An index must be named to use condition.")
@@ -58,7 +60,7 @@ class Index:
             raise ValueError("Index.fields must contain only strings with field names.")
         if include and not name:
             raise ValueError("A covering index must be named.")
-        if not isinstance(include, (type(None), list, tuple)):
+        if not isinstance(include, (NoneType, list, tuple)):
             raise ValueError("Index.include must be a list or tuple.")
         self.fields = list(fields)
         # A list of 2-tuple with the field name and ordering ('' or 'DESC').

django/utils/encoding.py

@@ -2,6 +2,7 @@ import codecs
 import datetime
 import locale
 from decimal import Decimal
+from types import NoneType
 from urllib.parse import quote
 
 from django.utils.functional import Promise
@@ -34,7 +35,7 @@ def smart_str(s, encoding="utf-8", strings_only=False, errors="strict"):
 
 
 _PROTECTED_TYPES = (
-    type(None),
+    NoneType,
     int,
     float,
     Decimal,

tests/migrations/test_writer.py

@@ -9,6 +9,7 @@ import re
 import sys
 import uuid
 import zoneinfo
+from types import NoneType
 from unittest import mock
 
 import custom_migration_operations.more_operations
@@ -797,7 +798,7 @@ class WriterTests(SimpleTestCase):
         self.assertEqual(result.keywords, value.keywords)
 
     def test_serialize_type_none(self):
-        self.assertSerializedEqual(type(None))
+        self.assertSerializedEqual(NoneType)
 
     def test_serialize_type_model(self):
         self.assertSerializedEqual(models.Model)