Add typing to spec cache

astroid/interpreter/_import/spec.py

@@ -15,7 +15,7 @@
 import types
 import warnings
 import zipimport
-from collections.abc import Iterator, Sequence
+from collections.abc import Callable, Iterator, Sequence
 from pathlib import Path
 from typing import Any, Literal, NamedTuple, Protocol
 
@@ -24,10 +24,10 @@
 
 from . import util
 
-_spec_cache = {}
+_spec_cache: dict[str, ModuleSpec] = {}
 
 
-def clear_spec_cache():
+def clear_spec_cache() -> None:
     _spec_cache.clear()
 
 
@@ -429,11 +429,13 @@ def _find_spec_with_path(
     raise ImportError(f"No module named {'.'.join(module_parts)}")
 
 
-def spec_cache(func):
-    def wrapper(*args):
-        key = ".".join(args[0])
+def spec_cache(
+    func: Callable[[list[str], Sequence[str] | None], ModuleSpec]
+) -> Callable[..., ModuleSpec]:
+    def wrapper(modpath: list[str], *args) -> ModuleSpec:
+        key = ".".join(modpath)
         if key not in _spec_cache:
-            _spec_cache[key] = func(*args)
+            _spec_cache[key] = func(modpath, *args)
 
         return _spec_cache[key]