Fix formfield() methods

Author: adamchainz

src/django_mysql/models/fields/dynamic.py

@@ -8,6 +8,7 @@
 from typing import Union
 from typing import cast
 
+from django import forms
 from django.core import checks
 from django.db.backends.base.base import BaseDatabaseWrapper
 from django.db.models import DateField
@@ -289,7 +290,7 @@ def deconstruct(self) -> DeconstructResult:
             kwargs["blank"] = False
         return name, path, args, kwargs
 
-    def formfield(self, *args: Any, **kwargs: Any) -> Any:
+    def formfield(self, *args: Any, **kwargs: Any) -> forms.Field | None:
         """
         Disabled in forms - there is no sensible way of editing this
         """

src/django_mysql/models/fields/lists.py

@@ -5,6 +5,7 @@
 from typing import Callable
 from typing import cast
 
+from django import forms
 from django.core import checks
 from django.db.backends.base.base import BaseDatabaseWrapper
 from django.db.models import CharField
@@ -154,7 +155,7 @@ def value_to_string(self, obj: Any) -> str:
         vals = self.value_from_object(obj)
         return self.get_prep_value(vals)
 
-    def formfield(self, **kwargs: Any) -> Any:
+    def formfield(self, **kwargs: Any) -> forms.Field | None:
         defaults = {
             "form_class": SimpleListField,
             "base_field": self.base_field.formfield(),

src/django_mysql/models/fields/sets.py

@@ -3,6 +3,7 @@
 from typing import Any
 from typing import cast
 
+from django import forms
 from django.core import checks
 from django.db.backends.base.base import BaseDatabaseWrapper
 from django.db.models import CharField
@@ -135,7 +136,7 @@ def value_to_string(self, obj: Any) -> str:
         vals = self.value_from_object(obj)
         return self.get_prep_value(vals)
 
-    def formfield(self, **kwargs: Any) -> Any:
+    def formfield(self, **kwargs: Any) -> forms.Field | None:
         defaults = {
             "form_class": SimpleSetField,
             "base_field": self.base_field.formfield(),