Replace TypeAlias _ClassLevelWidgetT with descriptor _WidgetTypeOrInstance

django-stubs/contrib/auth/forms.pyi

@@ -8,7 +8,6 @@ from django.contrib.auth.tokens import PasswordResetTokenGenerator
 from django.core.exceptions import ValidationError
 from django.db import models
 from django.db.models.fields import _ErrorMessagesDict
-from django.forms.fields import _ClassLevelWidgetT
 from django.forms.widgets import Widget
 from django.http.request import HttpRequest
 from django.utils.functional import _StrOrPromise
@@ -22,7 +21,6 @@ class ReadOnlyPasswordHashWidget(forms.Widget):
     def get_context(self, name: str, value: Any, attrs: dict[str, Any] | None) -> dict[str, Any]: ...
 
 class ReadOnlyPasswordHashField(forms.Field):
-    widget: _ClassLevelWidgetT
     def __init__(self, *args: Any, **kwargs: Any) -> None: ...
 
 class UsernameField(forms.CharField):

django-stubs/contrib/gis/forms/fields.pyi

@@ -3,7 +3,6 @@ from typing import Any
 from django import forms
 
 class GeometryField(forms.Field):
-    widget: Any
     geom_type: str
     srid: Any
     def __init__(self, *, srid: Any | None = ..., geom_type: Any | None = ..., **kwargs: Any) -> None: ...

django-stubs/contrib/postgres/forms/array.pyi

@@ -3,7 +3,6 @@ from typing import Any, ClassVar
 
 from django import forms
 from django.db.models.fields import _ErrorMessagesDict
-from django.forms.fields import _ClassLevelWidgetT
 from django.forms.utils import _DataT, _FilesT
 from django.forms.widgets import _OptAttrs
 
@@ -33,7 +32,6 @@ class SimpleArrayField(forms.CharField):
 
 class SplitArrayWidget(forms.Widget):
     template_name: str
-    widget: _ClassLevelWidgetT
     size: int
     def __init__(self, widget: forms.Widget | type[forms.Widget], size: int, **kwargs: Any) -> None: ...
     @property

django-stubs/contrib/postgres/forms/hstore.pyi

@@ -2,10 +2,8 @@ from typing import Any, ClassVar
 
 from django import forms
 from django.db.models.fields import _ErrorMessagesDict
-from django.forms.fields import _ClassLevelWidgetT
 
 class HStoreField(forms.CharField):
-    widget: _ClassLevelWidgetT
     default_error_messages: ClassVar[_ErrorMessagesDict]
     def prepare_value(self, value: Any) -> Any: ...
     def to_python(self, value: Any) -> dict[str, str | None]: ...  # type: ignore[override]

django-stubs/forms/fields.pyi

@@ -2,7 +2,7 @@ import datetime
 from collections.abc import Collection, Iterator, Sequence
 from decimal import Decimal
 from re import Pattern
-from typing import Any, ClassVar, Protocol, TypeAlias, type_check_only
+from typing import Any, ClassVar, Protocol, overload, type_check_only
 from uuid import UUID
 
 from django.core.files import File
@@ -15,20 +15,22 @@ from django.utils.choices import CallableChoiceIterator, _ChoicesCallable, _Choi
 from django.utils.datastructures import _PropertyDescriptor
 from django.utils.functional import _StrOrPromise
 
-# Problem: attribute `widget` is always of type `Widget` after field instantiation.
-# However, on class level it can be set to `Type[Widget]` too.
-# If we annotate it as `Union[Widget, Type[Widget]]`, every code that uses field
-# instances will not typecheck.
-# If we annotate it as `Widget`, any widget subclasses that do e.g.
-# `widget = Select` will not typecheck.
-# `Any` gives too much freedom, but does not create false positives.
-_ClassLevelWidgetT: TypeAlias = Any
+@type_check_only
+class _WidgetTypeOrInstance:
+    @overload
+    def __get__(self, instance: None, owner: type[Field]) -> type[Widget] | Widget: ...
+    @overload
+    def __get__(self, instance: Field, owner: type[Field]) -> Widget: ...
+    @overload
+    def __set__(self, instance: None, value: type[Widget] | Widget) -> None: ...
+    @overload
+    def __set__(self, instance: Field, value: Widget) -> None: ...
 
 class Field:
     initial: Any
     label: _StrOrPromise | None
     required: bool
-    widget: _ClassLevelWidgetT
+    widget: _WidgetTypeOrInstance
     hidden_widget: type[Widget]
     default_validators: list[_ValidatorCallable]
     default_error_messages: ClassVar[_ErrorMessagesDict]
@@ -319,7 +321,6 @@ class ChoiceField(Field):
         _ChoicesInput | _ChoicesCallable | CallableChoiceIterator,
         _ChoicesInput | CallableChoiceIterator,
     ]
-    widget: _ClassLevelWidgetT
     def __init__(
         self,
         *,
@@ -547,7 +548,6 @@ class JSONString(str): ...
 
 class JSONField(CharField):
     default_error_messages: ClassVar[_ErrorMessagesDict]
-    widget: _ClassLevelWidgetT
     encoder: Any
     decoder: Any
     def __init__(self, encoder: Any | None = None, decoder: Any | None = None, **kwargs: Any) -> None: ...

django-stubs/forms/models.pyi

@@ -8,7 +8,7 @@ from django.db.models.base import Model
 from django.db.models.fields import _AllLimitChoicesTo, _LimitChoicesTo
 from django.db.models.manager import Manager
 from django.db.models.query import QuerySet
-from django.forms.fields import ChoiceField, Field, _ClassLevelWidgetT
+from django.forms.fields import ChoiceField, Field
 from django.forms.forms import BaseForm, DeclarativeFieldsMetaclass
 from django.forms.formsets import BaseFormSet
 from django.forms.renderers import BaseRenderer
@@ -226,7 +226,6 @@ class InlineForeignKeyField(Field):
     help_text: _StrOrPromise
     required: bool
     show_hidden_initial: bool
-    widget: _ClassLevelWidgetT
     parent_instance: Model
     pk_field: bool
     to_field: str | None
@@ -296,7 +295,6 @@ class ModelMultipleChoiceField(ModelChoiceField[_M]):
     help_text: _StrOrPromise
     required: bool
     show_hidden_initial: bool
-    widget: _ClassLevelWidgetT
     hidden_widget: type[Widget]
     def __init__(self, queryset: Manager[_M] | QuerySet[_M] | None, **kwargs: Any) -> None: ...
     def to_python(self, value: Any) -> list[_M]: ...  # type: ignore[override]

tests/assert_type/contrib/auth/test_forms.py

@@ -0,0 +1,9 @@
+from django.contrib.auth.forms import ReadOnlyPasswordHashField, UsernameField
+from django.forms.widgets import Widget
+from typing_extensions import assert_type
+
+assert_type(ReadOnlyPasswordHashField.widget, type[Widget] | Widget)
+assert_type(ReadOnlyPasswordHashField().widget, Widget)
+
+assert_type(UsernameField.widget, type[Widget] | Widget)
+assert_type(UsernameField().widget, Widget)

tests/assert_type/contrib/gis/forms/test_fields.py

@@ -0,0 +1,36 @@
+from django.contrib.gis.forms import (
+    GeometryCollectionField,
+    GeometryField,
+    LineStringField,
+    MultiLineStringField,
+    MultiPointField,
+    MultiPolygonField,
+    PointField,
+    PolygonField,
+)
+from django.forms.widgets import Widget
+from typing_extensions import assert_type
+
+assert_type(GeometryField.widget, type[Widget] | Widget)
+assert_type(GeometryField().widget, Widget)
+
+assert_type(GeometryCollectionField.widget, type[Widget] | Widget)
+assert_type(GeometryCollectionField().widget, Widget)
+
+assert_type(PointField.widget, type[Widget] | Widget)
+assert_type(PointField().widget, Widget)
+
+assert_type(MultiPointField.widget, type[Widget] | Widget)
+assert_type(MultiPointField().widget, Widget)
+
+assert_type(LineStringField.widget, type[Widget] | Widget)
+assert_type(LineStringField().widget, Widget)
+
+assert_type(MultiLineStringField.widget, type[Widget] | Widget)
+assert_type(MultiLineStringField().widget, Widget)
+
+assert_type(PolygonField.widget, type[Widget] | Widget)
+assert_type(PolygonField().widget, Widget)
+
+assert_type(MultiPolygonField.widget, type[Widget] | Widget)
+assert_type(MultiPolygonField().widget, Widget)

tests/assert_type/contrib/postgres/forms/test_array.py

@@ -0,0 +1,15 @@
+from typing import cast
+
+from django.contrib.postgres.forms.array import SimpleArrayField, SplitArrayField
+from django.forms.fields import Field
+from django.forms.widgets import Widget
+from typing_extensions import assert_type
+
+base_field = cast(Field, ...)
+size = cast(int, ...)
+
+assert_type(SimpleArrayField.widget, type[Widget] | Widget)
+assert_type(SimpleArrayField(base_field).widget, Widget)
+
+assert_type(SplitArrayField.widget, type[Widget] | Widget)
+assert_type(SplitArrayField(base_field, size).widget, Widget)

tests/assert_type/contrib/postgres/forms/test_hstore.py

@@ -0,0 +1,6 @@
+from django.contrib.postgres.forms.hstore import HStoreField
+from django.forms.widgets import Widget
+from typing_extensions import assert_type
+
+assert_type(HStoreField.widget, type[Widget] | Widget)
+assert_type(HStoreField().widget, Widget)

tests/assert_type/contrib/postgres/forms/test_ranges.py

@@ -0,0 +1,20 @@
+from django.contrib.postgres.forms.ranges import (
+    DateRangeField,
+    DateTimeRangeField,
+    DecimalRangeField,
+    IntegerRangeField,
+)
+from django.forms.widgets import Widget
+from typing_extensions import assert_type
+
+assert_type(IntegerRangeField.widget, type[Widget] | Widget)
+assert_type(IntegerRangeField().widget, Widget)
+
+assert_type(DecimalRangeField.widget, type[Widget] | Widget)
+assert_type(DecimalRangeField().widget, Widget)
+
+assert_type(DateTimeRangeField.widget, type[Widget] | Widget)
+assert_type(DateTimeRangeField().widget, Widget)
+
+assert_type(DateRangeField.widget, type[Widget] | Widget)
+assert_type(DateRangeField().widget, Widget)

tests/assert_type/forms/test_fields.py

@@ -0,0 +1,121 @@
+from typing import cast
+
+from django.forms.fields import (
+    BooleanField,
+    CharField,
+    ChoiceField,
+    ComboField,
+    DateField,
+    DateTimeField,
+    DecimalField,
+    DurationField,
+    EmailField,
+    Field,
+    FileField,
+    FilePathField,
+    FloatField,
+    GenericIPAddressField,
+    ImageField,
+    IntegerField,
+    JSONField,
+    MultipleChoiceField,
+    MultiValueField,
+    NullBooleanField,
+    RegexField,
+    SlugField,
+    SplitDateTimeField,
+    TimeField,
+    TypedChoiceField,
+    TypedMultipleChoiceField,
+    URLField,
+    UUIDField,
+)
+from django.forms.widgets import Widget
+from typing_extensions import assert_type
+
+assert_type(CharField.widget, type[Widget] | Widget)
+assert_type(CharField().widget, Widget)
+
+assert_type(IntegerField.widget, type[Widget] | Widget)
+assert_type(IntegerField().widget, Widget)
+
+assert_type(FloatField.widget, type[Widget] | Widget)
+assert_type(FloatField().widget, Widget)
+
+assert_type(DecimalField.widget, type[Widget] | Widget)
+assert_type(DecimalField().widget, Widget)
+
+assert_type(DateField.widget, type[Widget] | Widget)
+assert_type(DateField().widget, Widget)
+
+assert_type(TimeField.widget, type[Widget] | Widget)
+assert_type(TimeField().widget, Widget)
+
+assert_type(DateTimeField.widget, type[Widget] | Widget)
+assert_type(DateTimeField().widget, Widget)
+
+assert_type(DurationField.widget, type[Widget] | Widget)
+assert_type(DurationField().widget, Widget)
+
+regex = cast(str, ...)
+
+assert_type(RegexField.widget, type[Widget] | Widget)
+assert_type(RegexField(regex).widget, Widget)
+
+assert_type(EmailField.widget, type[Widget] | Widget)
+assert_type(EmailField().widget, Widget)
+
+assert_type(FileField.widget, type[Widget] | Widget)
+assert_type(FileField().widget, Widget)
+
+assert_type(ImageField.widget, type[Widget] | Widget)
+assert_type(ImageField().widget, Widget)
+
+assert_type(URLField.widget, type[Widget] | Widget)
+assert_type(URLField().widget, Widget)
+
+assert_type(BooleanField.widget, type[Widget] | Widget)
+assert_type(BooleanField().widget, Widget)
+
+assert_type(NullBooleanField.widget, type[Widget] | Widget)
+assert_type(NullBooleanField().widget, Widget)
+
+assert_type(ChoiceField.widget, type[Widget] | Widget)
+assert_type(ChoiceField().widget, Widget)
+
+assert_type(TypedChoiceField.widget, type[Widget] | Widget)
+assert_type(TypedChoiceField().widget, Widget)
+
+assert_type(MultipleChoiceField.widget, type[Widget] | Widget)
+assert_type(MultipleChoiceField().widget, Widget)
+
+assert_type(TypedMultipleChoiceField.widget, type[Widget] | Widget)
+assert_type(TypedMultipleChoiceField().widget, Widget)
+
+fields = cast(list[Field], ...)
+
+assert_type(ComboField.widget, type[Widget] | Widget)
+assert_type(ComboField(fields).widget, Widget)
+
+assert_type(MultiValueField.widget, type[Widget] | Widget)
+assert_type(MultiValueField(fields).widget, Widget)
+
+path = cast(str, ...)
+
+assert_type(FilePathField.widget, type[Widget] | Widget)
+assert_type(FilePathField(path).widget, Widget)
+
+assert_type(SplitDateTimeField.widget, type[Widget] | Widget)
+assert_type(SplitDateTimeField().widget, Widget)
+
+assert_type(GenericIPAddressField.widget, type[Widget] | Widget)
+assert_type(GenericIPAddressField().widget, Widget)
+
+assert_type(SlugField.widget, type[Widget] | Widget)
+assert_type(SlugField().widget, Widget)
+
+assert_type(UUIDField.widget, type[Widget] | Widget)
+assert_type(UUIDField().widget, Widget)
+
+assert_type(JSONField.widget, type[Widget] | Widget)
+assert_type(JSONField().widget, Widget)

tests/assert_type/forms/test_models.py

@@ -0,0 +1,23 @@
+from typing import cast
+
+from django.db.models import Model, QuerySet
+from django.forms.models import InlineForeignKeyField, ModelChoiceField, ModelMultipleChoiceField
+from django.forms.widgets import Widget
+from typing_extensions import assert_type
+
+
+class TestModel(Model): ...
+
+
+testmodel_instance = cast(TestModel, ...)
+
+assert_type(InlineForeignKeyField.widget, type[Widget] | Widget)
+assert_type(InlineForeignKeyField(testmodel_instance).widget, Widget)
+
+testmodel_queryset = cast(QuerySet[TestModel], ...)
+
+assert_type(ModelChoiceField.widget, type[Widget] | Widget)
+assert_type(ModelChoiceField(testmodel_queryset).widget, Widget)
+
+assert_type(ModelMultipleChoiceField.widget, type[Widget] | Widget)
+assert_type(ModelMultipleChoiceField(testmodel_queryset).widget, Widget)