From f36fccb22c4e1fe25fe20694c3c0c1cf26581010 Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Wed, 25 Sep 2024 12:47:54 +0300
Subject: [PATCH] gh-66419: Make optional arguments with nargs=REMAINDER
 consume all arguments

It no longer stops at the first '--'.
---
 Lib/argparse.py                                    |  2 +-
 Lib/test/test_argparse.py                          | 14 ++++++++++++++
 .../2024-09-25-12-47-50.gh-issue-66419.DVSukU.rst  |  2 ++
 3 files changed, 17 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Library/2024-09-25-12-47-50.gh-issue-66419.DVSukU.rst

diff --git a/Lib/argparse.py b/Lib/argparse.py
index 690b2a9db9481b..ef825cdef92a37 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -2363,7 +2363,7 @@ def _get_nargs_pattern(self, action):
 
         # allow any number of options or arguments
         elif nargs == REMAINDER:
-            nargs_pattern = '([-AO]*)'
+            nargs_pattern = '(.*)'
 
         # allow one argument followed by any number of options or arguments
         elif nargs == PARSER:
diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
index ef05a6fefcffcc..be6a907f47b5bd 100644
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -6036,6 +6036,20 @@ def test_remainder(self):
         args = parser.parse_args(['--foo', 'a', '--', 'b', '--', 'c'])
         self.assertEqual(NS(foo='a', bar=['--', 'b', '--', 'c']), args)
 
+    def test_optional_remainder(self):
+        parser = argparse.ArgumentParser(exit_on_error=False)
+        parser.add_argument('--foo', nargs='...')
+        parser.add_argument('bar', nargs='*')
+
+        args = parser.parse_args(['--', '--foo', 'a', 'b'])
+        self.assertEqual(NS(foo=None, bar=['--foo', 'a', 'b']), args)
+        args = parser.parse_args(['--foo', '--', 'a', 'b'])
+        self.assertEqual(NS(foo=['--', 'a', 'b'], bar=[]), args)
+        args = parser.parse_args(['--foo', 'a', '--', 'b'])
+        self.assertEqual(NS(foo=['a', '--', 'b'], bar=[]), args)
+        args = parser.parse_args(['--foo', 'a', 'b', '--'])
+        self.assertEqual(NS(foo=['a', 'b', '--'], bar=[]), args)
+
     def test_subparser(self):
         parser = argparse.ArgumentParser(exit_on_error=False)
         parser.add_argument('foo')
diff --git a/Misc/NEWS.d/next/Library/2024-09-25-12-47-50.gh-issue-66419.DVSukU.rst b/Misc/NEWS.d/next/Library/2024-09-25-12-47-50.gh-issue-66419.DVSukU.rst
new file mode 100644
index 00000000000000..45da08bde7c311
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2024-09-25-12-47-50.gh-issue-66419.DVSukU.rst
@@ -0,0 +1,2 @@
+Optional argument with :ref:`nargs` equals to ``argparse.REMAINDER`` now
+consumes all remaining arguments, not only to the first ``'--'``.