Simplified pkg_resources._declare_state (#4346)

pkg_resources/__init__.py

@@ -27,7 +27,7 @@
 import time
 import re
 import types
-from typing import Any, Callable, Dict, Iterable, List, Protocol, Optional
+from typing import Callable, Dict, Iterable, List, Protocol, Optional, TypeVar
 import zipfile
 import zipimport
 import warnings
@@ -103,6 +103,8 @@
     stacklevel=2,
 )
 
+T = TypeVar("T")
+
 
 _PEP440_FALLBACK = re.compile(r"^v?(?P<safe>(?:[0-9]+!)?[0-9]+(?:\.[0-9]+)*)", re.I)
 
@@ -117,11 +119,12 @@ class PEP440Warning(RuntimeWarning):
 parse_version = packaging.version.Version
 
 
-_state_vars: Dict[str, Any] = {}
+_state_vars: Dict[str, str] = {}
 
 
-def _declare_state(vartype: str, **kw: object) -> None:
-    _state_vars.update(dict.fromkeys(kw, vartype))
+def _declare_state(vartype: str, varname: str, initial_value: T) -> T:
+    _state_vars[varname] = vartype
+    return initial_value
 
 
 def __getstate__():
@@ -2023,8 +2026,7 @@ def __init__(self, importer):
 
 _distribution_finders: Dict[
     type, Callable[[object, str, bool], Iterable["Distribution"]]
-] = {}
-_declare_state('dict', _distribution_finders=_distribution_finders)
+] = _declare_state('dict', '_distribution_finders', {})
 
 
 def register_finder(importer_type, distribution_finder):
@@ -2199,10 +2201,10 @@ def resolve_egg_link(path):
 
 _namespace_handlers: Dict[
     type, Callable[[object, str, str, types.ModuleType], Optional[str]]
-] = {}
-_declare_state('dict', _namespace_handlers=_namespace_handlers)
-_namespace_packages: Dict[Optional[str], List[str]] = {}
-_declare_state('dict', _namespace_packages=_namespace_packages)
+] = _declare_state('dict', '_namespace_handlers', {})
+_namespace_packages: Dict[Optional[str], List[str]] = _declare_state(
+    'dict', '_namespace_packages', {}
+)
 
 
 def register_namespace_handler(importer_type, namespace_handler):
@@ -3301,8 +3303,7 @@ def _initialize_master_working_set():
     Invocation by other packages is unsupported and done
     at their own risk.
     """
-    working_set = WorkingSet._build_master()
-    _declare_state('object', working_set=working_set)
+    working_set = _declare_state('object', 'working_set', WorkingSet._build_master())
 
     require = working_set.require
     iter_entry_points = working_set.iter_entry_points