GH-139809: Fix argparse subcommand prog not respecting color environment variables

Lib/argparse.py

@@ -1963,7 +1963,7 @@ def add_subparsers(self, **kwargs):
             positionals = self._get_positional_actions()
             groups = self._mutually_exclusive_groups
             formatter.add_usage(None, positionals, groups, '')
-            kwargs['prog'] = formatter.format_help().strip()
+            kwargs['prog'] = formatter._decolor(formatter.format_help().strip())
 
         # create the parsers action and add it to the positionals list
         parsers_class = self._pop_action_class(kwargs, 'parsers')

Lib/test/test_argparse.py

@@ -7356,6 +7356,28 @@ def __init__(self, prog):
         '''))
 
 
+class TestColorEnvironment(TestCase):
+    """Tests for color behavior with environment variable changes."""
+
+    def test_subparser_respects_no_color_environment(self):
+        # Cleanup to ensure environment is properly reset
+        self.addCleanup(os.environ.pop, 'FORCE_COLOR', None)
+        self.addCleanup(os.environ.pop, 'NO_COLOR', None)
+
+        # Create parser with FORCE_COLOR, capturing colored prog
+        os.environ['FORCE_COLOR'] = '1'
+        parser = argparse.ArgumentParser(prog='complex')
+        sub = parser.add_subparsers(dest='command')
+        demo_parser = sub.add_parser('demo')
+
+        # Switch to NO_COLOR environment
+        os.environ.pop('FORCE_COLOR', None)
+        os.environ['NO_COLOR'] = '1'
+
+        # Subparser help should have no color codes
+        help_text = demo_parser.format_help()
+        self.assertNotIn('\x1b[', help_text)
+
 class TestModule(unittest.TestCase):
     def test_deprecated__version__(self):
         with self.assertWarnsRegex(