Add importlib.resources.files for Python 3.9 (#4807)

Co-authored-by: hauntsaninja <>
Co-authored-by: Sebastian Rittau <srittau@rittau.biz>

stdlib/3/importlib/abc.pyi

@@ -3,6 +3,7 @@ import sys
 import types
 from abc import ABCMeta, abstractmethod
 from typing import IO, Any, Iterator, Mapping, Optional, Sequence, Tuple, Union
+from typing_extensions import Literal
 
 # Loader is exported from this module, but for circular import reasons
 # exists in its own stub file (with ModuleSpec and ModuleType).
@@ -70,3 +71,27 @@ if sys.version_info >= (3, 7):
         def is_resource(self, name: str) -> bool: ...
         @abstractmethod
         def contents(self) -> Iterator[str]: ...
+
+if sys.version_info >= (3, 9):
+    from typing import Protocol, runtime_checkable
+    @runtime_checkable
+    class Traversable(Protocol):
+        @abstractmethod
+        def iterdir(self) -> Iterator[Traversable]: ...
+        @abstractmethod
+        def read_bytes(self) -> bytes: ...
+        @abstractmethod
+        def read_text(self, encoding: Optional[str] = ...) -> str: ...
+        @abstractmethod
+        def is_dir(self) -> bool: ...
+        @abstractmethod
+        def is_file(self) -> bool: ...
+        @abstractmethod
+        def joinpath(self, child: Traversable) -> Traversable: ...
+        @abstractmethod
+        def __truediv__(self, child: Traversable) -> Traversable: ...
+        @abstractmethod
+        def open(self, mode: Literal["r", "rb"] = ..., *args: Any, **kwargs: Any) -> IO: ...
+        @property
+        @abstractmethod
+        def name(self) -> str: ...

stdlib/3/importlib/resources.pyi

@@ -16,3 +16,7 @@ if sys.version_info >= (3, 7):
     def path(package: Package, resource: Resource) -> ContextManager[Path]: ...
     def is_resource(package: Package, name: str) -> bool: ...
     def contents(package: Package) -> Iterator[str]: ...
+
+if sys.version_info >= (3, 9):
+    from importlib.abc import Traversable
+    def files(package: Package) -> Traversable: ...

tests/stubtest_whitelists/py39.txt

@@ -51,6 +51,7 @@ hmac.new  # Stub is a white lie; see comments in the stub
 http.client.HTTPSConnection.__init__
 http.cookiejar.DefaultCookiePolicy.__init__
 http.server.SimpleHTTPRequestHandler.__init__
+importlib.abc.Traversable.__init__  # Inherits __init__ from typing.Protocol
 importlib.metadata.DistributionFinder.Context.pattern
 importlib.metadata.EntryPointBase
 ipaddress.IPv4Interface.hostmask