Fix CountryField type annotation to accept type[Countries] class

Fixes #482. The stub file incorrectly declared the countries parameter
as accepting a Countries instance instead of a Countries class, causing
mypy errors when passing custom Countries subclasses.

Also removed unnecessary mypy exclusion of tests directory, which would
have caught this issue earlier.

Author: SmileyChris

changes/482.bugfix.md

@@ -0,0 +1 @@
+Fixed type annotation for `CountryField.countries` parameter in stub file to accept `type[Countries]` instead of `Countries` instance, resolving mypy errors when using custom Countries subclasses. Also removed unnecessary exclusion of tests from mypy checking.

django_countries/fields.pyi

@@ -113,7 +113,7 @@ class CountryField(models.CharField):
         multiple: Literal[False] = False,
         null: Literal[False] = False,
         blank: bool = False,
-        countries: Countries | None = None,
+        countries: type[Countries] | None = None,
         countries_flag_url: str | None = None,
         countries_str_attr: str = "code",
         blank_label: str | None = None,
@@ -128,7 +128,7 @@ class CountryField(models.CharField):
         multiple: Literal[False] = False,
         null: Literal[True],
         blank: bool = True,
-        countries: Countries | None = None,
+        countries: type[Countries] | None = None,
         countries_flag_url: str | None = None,
         countries_str_attr: str = "code",
         blank_label: str | None = None,
@@ -145,7 +145,7 @@ class CountryField(models.CharField):
         blank: bool = False,
         multiple_sort: bool = True,
         multiple_unique: bool = True,
-        countries: Countries | None = None,
+        countries: type[Countries] | None = None,
         countries_flag_url: str | None = None,
         countries_str_attr: str = "code",
         **kwargs: Any,
@@ -161,7 +161,7 @@ class CountryField(models.CharField):
         blank: bool = True,
         multiple_sort: bool = True,
         multiple_unique: bool = True,
-        countries: Countries | None = None,
+        countries: type[Countries] | None = None,
         countries_flag_url: str | None = None,
         countries_str_attr: str = "code",
         **kwargs: Any,

pyproject.toml

@@ -93,9 +93,6 @@ exclude_lines = ["pragma: no cover", "@overload", "if TYPE_CHECKING:"]
 plugins = ["mypy_django_plugin.main"]
 disallow_untyped_calls = true
 python_version = "3.9"
-exclude = [
-    'django_countries/tests/',
-]
 
 [[tool.mypy.overrides]]
 module = "mypy_django_plugin.*"