From 732cfbb0607a558004a58f738ffb55c8cf663403 Mon Sep 17 00:00:00 2001
From: 180909 <734461790@qq.com>
Date: Tue, 17 Oct 2023 14:06:55 +0800
Subject: [PATCH] gho-109475: argument get the value is `--`

---
 Lib/argparse.py           | 3 +++
 Lib/test/test_argparse.py | 6 ++++++
 2 files changed, 9 insertions(+)

diff --git a/Lib/argparse.py b/Lib/argparse.py
index a32884db80d1ea..2059ec880c6a2d 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -2536,6 +2536,9 @@ def _get_values(self, action, arg_strings):
         elif action.nargs == SUPPRESS:
             value = SUPPRESS
 
+        elif len(arg_strings) == 0:
+            value = '--'
+
         # all other types of nargs produce a list
         else:
             value = [self._get_value(action, v) for v in arg_strings]
diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
index 7c1f5d36999a3d..295fda5dfba210 100644
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -5405,6 +5405,12 @@ def test_zero_or_more_optional(self):
         args = parser.parse_args([])
         self.assertEqual(NS(x=[]), args)
 
+    def test_double_dash(self):
+        parser = argparse.ArgumentParser()
+        parser.add_argument('--foo')
+        args = parser.parse_args(['--foo=--'])
+        self.assertEqual(NS(foo='--'), args)
+
 
 # ===========================
 # parse_intermixed_args tests