From 78965e1ae2c80f92d403aa891e81a6de92d47c62 Mon Sep 17 00:00:00 2001
From: Savannah Ostrowski <savannah@python.org>
Date: Fri, 24 Jul 2026 14:45:28 -0700
Subject: [PATCH 1/2] Accept string-like proxy objects in colorized argparse
 help

---
 Lib/argparse.py           |  2 +-
 Lib/test/test_argparse.py | 30 ++++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/Lib/argparse.py b/Lib/argparse.py
index f8739d031e01c5..c87ac7e34b0c4d 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -760,7 +760,7 @@ def colorize(match):
             return spec % params
 
         return self._apply_text_markup(
-            _re.sub(fmt_spec, colorize, help_string, flags=_re.VERBOSE)
+            _re.sub(fmt_spec, colorize, str(help_string), flags=_re.VERBOSE)
         )
 
     def _iter_indented_subactions(self, action):
diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
index 442cbb1aaadfe3..edd145382a4a14 100644
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -7898,6 +7898,36 @@ def test_backtick_markup_in_argument_help_color_disabled(self):
         self.assertIn("set the `foo` value", help_text)
         self.assertNotIn("\x1b[", help_text)
 
+    def test_argument_help_interpolation_accepts_string_like_proxy(self):
+        class LazyStr:
+            def __init__(self, message):
+                self._message = message
+
+            def __str__(self):
+                return self._message
+
+            def __getattr__(self, name):
+                return getattr(str(self), name)
+
+            def __contains__(self, item):
+                return item in self._message
+
+            def __mod__(self, other):
+                return self._message % other
+
+        parser = argparse.ArgumentParser(prog="PROG", color=True)
+        parser.add_argument(
+            "--foo",
+            default="bar",
+            help=LazyStr("foo (default: %(default)s)"),
+        )
+
+        interp = self.theme.interpolated_value
+        reset = self.theme.reset
+
+        help_text = parser.format_help()
+        self.assertIn(f"foo (default: {interp}bar{reset})", help_text)
+
     def test_help_with_format_specifiers(self):
         # GH-142950: format specifiers like %x should work with color=True
         parser = argparse.ArgumentParser(prog='PROG', color=True)

From c9ca9a7c35b9445e3d8a368e4f680af87bdca431 Mon Sep 17 00:00:00 2001
From: "blurb-it[bot]" <43283697+blurb-it[bot]@users.noreply.github.com>
Date: Fri, 24 Jul 2026 21:49:50 +0000
Subject: [PATCH 2/2] =?UTF-8?q?=F0=9F=93=9C=F0=9F=A4=96=20Added=20by=20blu?=
 =?UTF-8?q?rb=5Fit.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../next/Library/2026-07-24-21-49-45.gh-issue-148468.pHoF_Q.rst  | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Library/2026-07-24-21-49-45.gh-issue-148468.pHoF_Q.rst

diff --git a/Misc/NEWS.d/next/Library/2026-07-24-21-49-45.gh-issue-148468.pHoF_Q.rst b/Misc/NEWS.d/next/Library/2026-07-24-21-49-45.gh-issue-148468.pHoF_Q.rst
new file mode 100644
index 00000000000000..d1d0deb139bc20
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-07-24-21-49-45.gh-issue-148468.pHoF_Q.rst
@@ -0,0 +1 @@
+Fix a regression in :mod:`argparse` where colorized argument help containing format specifiers did not accept string-like proxy objects.