python · savannahostrowski · Oct 9, 2025 · Oct 9, 2025
@@ -1960,7 +1960,9 @@ def add_subparsers(self, **kwargs):
        # prog defaults to the usage message of this parser, skipping
        # optional arguments and with no "usage:" prefix
        if kwargs.get('prog') is None:
-            formatter = self._get_formatter()
+            # Create formatter without color to avoid storing ANSI codes in prog
+            formatter = self.formatter_class(prog=self.prog)
+            formatter._set_color(False)
            positionals = self._get_positional_actions()
            groups = self._mutually_exclusive_groups
            formatter.add_usage(None, positionals, groups, '')

@@ -22,6 +22,7 @@
    captured_stderr,
    force_not_colorized,
    force_not_colorized_test_class,
+    swap_attr,
 )
 from test.support import import_helper
 from test.support import os_helper
@@ -7128,7 +7129,8 @@ class TestColorized(TestCase):
    def setUp(self):
        super().setUp()
        # Ensure color even if ran with NO_COLOR=1
-        _colorize.can_colorize = lambda *args, **kwargs: True
+        self.enterContext(swap_attr(_colorize, 'can_colorize',
+                                     lambda *args, **kwargs: True))
        self.theme = _colorize.get_theme(force_color=True).argparse

    def test_argparse_color(self):
@@ -7355,6 +7357,17 @@ def __init__(self, prog):
                 {short_b}+f{reset}, {long_b}++foo{reset} {label_b}FOO{reset}  foo help
        '''))

+    def test_subparser_prog_is_stored_without_color(self):
+        parser = argparse.ArgumentParser(prog='complex', color=True)
+        sub = parser.add_subparsers(dest='command')
+        demo_parser = sub.add_parser('demo')
+
+        self.assertNotIn('\x1b[', demo_parser.prog)
+
+        demo_parser.color = False
+        help_text = demo_parser.format_help()
+        self.assertNotIn('\x1b[', help_text)
+

 def tearDownModule():
    # Remove global references to avoid looking like we have refleaks.

diff --git a/Misc/NEWS.d/next/Library/2025-10-09-03-06-19.gh-issue-139809.lzHJNu.rst b/Misc/NEWS.d/next/Library/2025-10-09-03-06-19.gh-issue-139809.lzHJNu.rst
@@ -0,0 +1 @@
+Prevent premature colorization of subparser ``prog`` in :meth:`argparse.ArgumentParser.add_subparsers` to respect color environment variable changes after parser creation.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Prevent premature colorization of subparser ``prog`` in :meth:`argparse.ArgumentParser.add_subparsers` to respect color environment variable changes after parser creation.