Move wsgiref.types to _typeshed.wsgi (#4175)

Re-export the types from wsgiref.types for now to avoid breaking
existing code. wsgiref.types should be removed eventually.

Also, reduce the boilerplate description in _typeshed/wsgi.pyi as it
mirrors the description in _typeshed/__init__.pyi.

stdlib/2and3/_typeshed/wsgi.pyi

@@ -0,0 +1,32 @@
+# Types to support PEP 3333 (WSGI)
+#
+# This module doesn't exist at runtime and neither do the types defined in this
+# file. They are provided for type checking purposes.
+
+from sys import _OptExcInfo
+from typing import Callable, Dict, Iterable, List, Any, Text, Protocol, Tuple, Optional
+
+class StartResponse(Protocol):
+    def __call__(self, status: str, headers: List[Tuple[str, str]], exc_info: Optional[_OptExcInfo] = ...) -> Callable[[bytes], Any]: ...
+
+WSGIEnvironment = Dict[Text, Any]
+WSGIApplication = Callable[[WSGIEnvironment, StartResponse], Iterable[bytes]]
+
+# WSGI input streams per PEP 3333
+class InputStream(Protocol):
+    def read(self, size: int = ...) -> bytes: ...
+    def readline(self, size: int = ...) -> bytes: ...
+    def readlines(self, hint: int = ...) -> List[bytes]: ...
+    def __iter__(self) -> Iterable[bytes]: ...
+
+# WSGI error streams per PEP 3333
+class ErrorStream(Protocol):
+    def flush(self) -> None: ...
+    def write(self, s: str) -> None: ...
+    def writelines(self, seq: List[str]) -> None: ...
+
+class _Readable(Protocol):
+    def read(self, size: int = ...) -> bytes: ...
+# Optional file wrapper in wsgi.file_wrapper
+class FileWrapper(Protocol):
+    def __call__(self, file: _Readable, block_size: int = ...) -> Iterable[bytes]: ...

stdlib/2and3/wsgiref/types.pyi

@@ -1,44 +1,3 @@
-# Type declaration for a WSGI Function
-#
-# wsgiref/types.py doesn't exist and neither do the types defined in this
-# file. They are provided for type checking purposes.
-#
-# This means you cannot simply import wsgiref.types in your code. Instead,
-# use the `TYPE_CHECKING` flag from the typing module:
-#
-#   from typing import TYPE_CHECKING
-#
-#   if TYPE_CHECKING:
-#       from wsgiref.types import WSGIApplication
-#
-# This import is now only taken into account by the type checker. Consequently,
-# you need to use 'WSGIApplication' and not simply WSGIApplication when type
-# hinting your code.  Otherwise Python will raise NameErrors.
+# Obsolete, use _typeshed.wsgi directly.
 
-from sys import _OptExcInfo
-from typing import Callable, Dict, Iterable, List, Any, Text, Protocol, Tuple, Optional
-
-class StartResponse(Protocol):
-    def __call__(self, status: str, headers: List[Tuple[str, str]], exc_info: Optional[_OptExcInfo] = ...) -> Callable[[bytes], Any]: ...
-
-WSGIEnvironment = Dict[Text, Any]
-WSGIApplication = Callable[[WSGIEnvironment, StartResponse], Iterable[bytes]]
-
-# WSGI input streams per PEP 3333
-class InputStream(Protocol):
-    def read(self, size: int = ...) -> bytes: ...
-    def readline(self, size: int = ...) -> bytes: ...
-    def readlines(self, hint: int = ...) -> List[bytes]: ...
-    def __iter__(self) -> Iterable[bytes]: ...
-
-# WSGI error streams per PEP 3333
-class ErrorStream(Protocol):
-    def flush(self) -> None: ...
-    def write(self, s: str) -> None: ...
-    def writelines(self, seq: List[str]) -> None: ...
-
-class _Readable(Protocol):
-    def read(self, size: int = ...) -> bytes: ...
-# Optional file wrapper in wsgi.file_wrapper
-class FileWrapper(Protocol):
-    def __call__(self, file: _Readable, block_size: int = ...) -> Iterable[bytes]: ...
+from _typeshed.wsgi import *

stdlib/2and3/wsgiref/validate.pyi

@@ -1,7 +1,7 @@
 import sys
 from typing import Any, Iterable, Iterator, Optional, NoReturn, Callable
 
-from wsgiref.types import WSGIApplication, InputStream, ErrorStream
+from _typeshed.wsgi import WSGIApplication, InputStream, ErrorStream
 
 class WSGIWarning(Warning): ...