Use protocols instead of importlib.abc.Loader/MetaPathFinder/PathEntryFinder (#11890)

stdlib/_typeshed/importlib.pyi

@@ -0,0 +1,18 @@
+# Implicit protocols used in importlib.
+# We intentionally omit deprecated and optional methods.
+
+from collections.abc import Sequence
+from importlib.machinery import ModuleSpec
+from types import ModuleType
+from typing import Protocol
+
+__all__ = ["LoaderProtocol", "MetaPathFinderProtocol", "PathEntryFinderProtocol"]
+
+class LoaderProtocol(Protocol):
+    def load_module(self, fullname: str, /) -> ModuleType: ...
+
+class MetaPathFinderProtocol(Protocol):
+    def find_spec(self, fullname: str, path: Sequence[str] | None, target: ModuleType | None = ..., /) -> ModuleSpec | None: ...
+
+class PathEntryFinderProtocol(Protocol):
+    def find_spec(self, fullname: str, target: ModuleType | None = ..., /) -> ModuleSpec | None: ...