GH-142928: Add deprecation warning for removal of color on HelpFormatter

Doc/whatsnew/3.15.rst

@@ -1078,6 +1078,12 @@
 New deprecations
 ----------------
 
+* :mod:`argparse`:
+
+  * The *color* parameter of :class:`~argparse.HelpFormatter` is deprecated.
+    Use the *color* parameter of :class:`~argparse.ArgumentParser` instead.
+    (Contributed by Savannah Ostrowski in :gh:`142946`.)
+
 * CLI:
 
   * Deprecate :option:`-b` and :option:`!-bb` command-line options

Lib/argparse.py

@@ -166,7 +166,17 @@ def __init__(
         indent_increment=2,
         max_help_position=24,
         width=None,
+        color=None,
     ):
+        if color is not None:
+            import warnings
+            warnings.warn(
+                "The 'color' parameter is deprecated. "
+                "Set 'color' in ArgumentParser instead.",
+                DeprecationWarning,
+                stacklevel=2,
+            )
+
         # default setting for width
         if width is None:
             import shutil

Lib/test/test_argparse.py

@@ -5702,6 +5702,12 @@ def test_direct_formatter_instantiation(self):
         help_text = formatter.format_help()
         self.assertEqual(help_text, "usage: program\n")
 
+    def test_formatter_color_parameter_deprecated(self):
+        with self.assertWarns(DeprecationWarning) as cm:
+            argparse.HelpFormatter(prog="program", color=True)
+        self.assertIn("'color' parameter is deprecated", str(cm.warning))
+        self.assertIn("ArgumentParser", str(cm.warning))
+
 # =====================================
 # Optional/Positional constructor tests
 # =====================================

Misc/NEWS.d/next/Library/2025-12-18-17-13-10.gh-issue-142928.bcgx78.rst

@@ -0,0 +1 @@
+Deprecate :class:`~argparse.HelpFormatter`'s *color* parameter. Users should use the *color* parameter on :class:`~argparse.ArgumentParser` instead.