[pull] main from python:main

Doc/library/argparse.rst

@@ -1564,12 +1564,12 @@ it exits and prints the error along with a usage message::
    >>> # invalid option
    >>> parser.parse_args(['--bar'])
    usage: PROG [-h] [--foo FOO] [bar]
-   PROG: error: no such option: --bar
+   PROG: error: unrecognized arguments: --bar
 
    >>> # wrong number of arguments
    >>> parser.parse_args(['spam', 'badger'])
    usage: PROG [-h] [--foo FOO] [bar]
-   PROG: error: extra arguments found: badger
+   PROG: error: unrecognized arguments: badger
 
 
 Arguments containing ``-``
@@ -1606,7 +1606,7 @@ there are no options in the parser that look like negative numbers::
    >>> # negative number options present, so -2 is an option
    >>> parser.parse_args(['-2'])
    usage: PROG [-h] [-1 ONE] [foo]
-   PROG: error: no such option: -2
+   PROG: error: unrecognized arguments: -2
 
    >>> # negative number options present, so both -1s are options
    >>> parser.parse_args(['-1', '-1'])

Lib/argparse.py

@@ -2917,11 +2917,14 @@ def print_help(self, file=None):
         self._print_message(help_text, file)
 
     def _print_message(self, message, file=None):
-        if message:
-            file = file or _sys.stderr
+        if not message:
+            return
+        if file is None:
+            file = _sys.stderr
+        if file is not None:
             try:
                 file.write(message)
-            except (AttributeError, OSError):
+            except OSError:
                 pass
 
     def _get_theme(self, file=None):

Lib/test/test_argparse.py

@@ -80,6 +80,24 @@ def test_skip_invalid_stdout(self):
                 func()
                 self.assertRegex(mocked_stderr.getvalue(), r'usage:')
 
+    def test_invalid_file_only(self):
+        parser = argparse.ArgumentParser()
+        for func in (parser.print_usage, parser.print_help):
+            for invalid_f in ("invalid file", "", 0):
+                with (
+                    self.subTest(func=func, invalid_f=invalid_f),
+                    self.assertRaises(AttributeError),
+                ):
+                    func(file=invalid_f)
+
+    def test_exit_when_stderr_oserror(self):
+        parser = argparse.ArgumentParser()
+        with (mock.patch('argparse._sys.stderr.write',
+                         side_effect=OSError('not raise this')),
+              self.assertRaises(SystemExit),
+              ):
+            parser.exit(status=0, message='foo')
+
 
 class TestLazyImports(unittest.TestCase):
     LAZY_IMPORTS = {

Lib/typing.py

@@ -25,6 +25,7 @@
 import collections.abc
 import copyreg
 import functools
+import keyword
 import operator
 import sys
 import types
@@ -998,8 +999,12 @@ def _make_forward_ref(code, *, parent_fwdref=None, **kwargs):
         if parent_fwdref.__owner__ is not None:
             kwargs['owner'] = parent_fwdref.__owner__
     forward_ref = annotationlib.ForwardRef(code, **kwargs)
-    # For compatibility, eagerly compile the forwardref's code.
-    forward_ref.__forward_code__
+    # For compatibility, eagerly compile the forwardref's code so that any
+    # SyntaxError is raised immediately rather than when the forward
+    # reference is evaluated. Similar to 'ForwardRef.evaluate()', we only compile
+    # it if necessary:
+    if not (code.isidentifier() and not keyword.iskeyword(code)):
+        forward_ref.__forward_code__
     return forward_ref
 
 

Misc/NEWS.d/next/Library/2026-07-18-16-05-38.gh-issue-153967.-OUNXe.rst

@@ -0,0 +1,3 @@
+:meth:`argparse.ArgumentParser.print_usage` and
+:meth:`argparse.ArgumentParser.print_help` won't silently fail when an invalid
+file object is specified. Patch by Timothy Poon.