[importlib] Add MetaPathFinder/PathEntryFinder.discover for Python 3.15 (#16158)

Author: aminalaee

stdlib/@tests/stubtest_allowlists/py315.txt

@@ -4,7 +4,6 @@
 
 _frozen_importlib.BuiltinImporter.load_module
 _frozen_importlib.FrozenImporter.load_module
-_frozen_importlib_external.FileFinder.discover
 _frozen_importlib_external.NamespaceLoader.load_module
 _frozen_importlib_external.NamespacePath
 _frozen_importlib_external.PathFinder.discover
@@ -22,8 +21,6 @@ dataclasses._MISSING_TYPE
 dataclasses.field
 importlib._abc.Loader.load_module
 importlib._bootstrap_external.NamespacePath
-importlib.abc.MetaPathFinder.discover
-importlib.abc.PathEntryFinder.discover
 importlib.resources._common.package_to_anchor
 mailbox._ProxyFile.__class_getitem__
 multiprocessing.process.BaseProcess.__init__

stdlib/importlib/abc.pyi

@@ -3,7 +3,7 @@ import sys
 import types
 from _typeshed import ReadableBuffer, StrPath
 from abc import ABCMeta, abstractmethod
-from collections.abc import Iterator, Mapping, Sequence
+from collections.abc import Iterable, Iterator, Mapping, Sequence
 from importlib import _bootstrap_external
 from importlib._abc import Loader as Loader
 from importlib.machinery import ModuleSpec
@@ -77,6 +77,8 @@ class MetaPathFinder(metaclass=ABCMeta):
     def find_spec(
         self, fullname: str, path: Sequence[str] | None, target: types.ModuleType | None = ..., /
     ) -> ModuleSpec | None: ...
+    if sys.version_info >= (3, 15):
+        def discover(self, parent: ModuleSpec | None = None) -> Iterable[ModuleSpec]: ...
 
 class PathEntryFinder(metaclass=ABCMeta):
     if sys.version_info < (3, 12):
@@ -88,6 +90,8 @@ class PathEntryFinder(metaclass=ABCMeta):
     def invalidate_caches(self) -> None: ...
     # Not defined on the actual class, but expected to exist.
     def find_spec(self, fullname: str, target: types.ModuleType | None = ...) -> ModuleSpec | None: ...
+    if sys.version_info >= (3, 15):
+        def discover(self, parent: ModuleSpec | None = None) -> Iterable[ModuleSpec]: ...
 
 class FileLoader(_bootstrap_external.FileLoader, ResourceLoader, ExecutionLoader, metaclass=ABCMeta):
     name: str