Revert "gh-85567: Register a cleanup function to close files for FileType objects in argparse (#32257)" (#91771)

This reverts commit 328dbc051f84bd5fdf61101bb4fa61d85f8b7feb.

Lib/argparse.py

@@ -84,7 +84,7 @@ __all__ = [
     'ZERO_OR_MORE',
 ]
 
-import atexit as _atexit
+
 import os as _os
 import re as _re
 import sys as _sys
@@ -1268,12 +1268,8 @@ class FileType(object):
 
         # all other arguments are used as file names
         try:
-            fh = open(string, self._mode, self._bufsize, self._encoding, self._errors)
-
-            # Register cleanup function to close file
-            _atexit.register(fh.close)
-
-            return fh
+            return open(string, self._mode, self._bufsize, self._encoding,
+                        self._errors)
         except OSError as e:
             args = {'filename': string, 'error': e}
             message = _("can't open '%(filename)s': %(error)s")

Misc/ACKS

@@ -313,7 +313,6 @@ Nicolas Chauvat
 Jerry Chen
 Michael Chermside
 Ingrid Cheung
-Adam Chhina
 Terry Chia
 Albert Chin-A-Young
 Adal Chiriliuc

Misc/NEWS.d/next/Library/2022-04-02-14-40-53.bpo-41395.Y1ZVvT.rst

@@ -1,3 +0,0 @@
-FileType objects from argparse may not be closed and lead to
-ResourceWarning. Register a file.close function with atexit for FileType
-objects to ensure they are closed. Patch Contributed by Adam Chhina.