Fix ConfigHandler generic

setuptools/config/setupcfg.py

@@ -27,7 +27,6 @@
     List,
     Tuple,
     TypeVar,
-    Union,
     cast,
 )
 
@@ -53,7 +52,7 @@
 while the second element of the tuple is the option value itself
 """
 AllCommandOptions = Dict["str", SingleCommandOptions]  # cmd name => its options
-Target = TypeVar("Target", bound=Union["Distribution", "DistributionMetadata"])
+Target = TypeVar("Target", "Distribution", "DistributionMetadata")
 
 
 def read_configuration(
@@ -96,7 +95,7 @@ def _apply(
     filepath: StrPath,
     other_files: Iterable[StrPath] = (),
     ignore_option_errors: bool = False,
-) -> tuple[ConfigHandler, ...]:
+) -> tuple[ConfigMetadataHandler, ConfigOptionsHandler]:
     """Read configuration from ``filepath`` and applies to the ``dist`` object."""
     from setuptools.dist import _Distribution
 
@@ -122,7 +121,7 @@ def _apply(
     return handlers
 
 
-def _get_option(target_obj: Target, key: str):
+def _get_option(target_obj: Distribution | DistributionMetadata, key: str):
     """
     Given a target object and option key, get that option from
     the target object, either through a get_{key} method or
@@ -134,10 +133,14 @@ def _get_option(target_obj: Target, key: str):
     return getter()
 
 
-def configuration_to_dict(handlers: tuple[ConfigHandler, ...]) -> dict:
+def configuration_to_dict(
+    handlers: Iterable[
+        ConfigHandler[Distribution] | ConfigHandler[DistributionMetadata]
+    ],
+) -> dict:
     """Returns configuration data gathered by given handlers as a dict.
 
-    :param list[ConfigHandler] handlers: Handlers list,
+    :param Iterable[ConfigHandler] handlers: Handlers list,
         usually from parse_configuration()
 
     :rtype: dict
@@ -254,7 +257,7 @@ def __init__(
         ensure_discovered: expand.EnsurePackagesDiscovered,
     ):
         self.ignore_option_errors = ignore_option_errors
-        self.target_obj = target_obj
+        self.target_obj: Target = target_obj
         self.sections = dict(self._section_options(options))
         self.set_options: list[str] = []
         self.ensure_discovered = ensure_discovered

setuptools/tests/config/test_setupcfg.py

@@ -7,7 +7,7 @@
 import pytest
 from packaging.requirements import InvalidRequirement
 
-from setuptools.config.setupcfg import ConfigHandler, read_configuration
+from setuptools.config.setupcfg import ConfigHandler, Target, read_configuration
 from setuptools.dist import Distribution, _Distribution
 from setuptools.warnings import SetuptoolsDeprecationWarning
 
@@ -16,7 +16,7 @@
 from distutils.errors import DistutilsFileError, DistutilsOptionError
 
 
-class ErrConfigHandler(ConfigHandler):
+class ErrConfigHandler(ConfigHandler[Target]):
     """Erroneous handler. Fails to implement required methods."""
 
     section_prefix = "**err**"