gh-99749: Add closest choice if exists in Argparser if wrong choice picked

Lib/argparse.py

@@ -84,7 +84,7 @@
     'ZERO_OR_MORE',
 ]
 
-
+import difflib as _difflib
 import os as _os
 import re as _re
 import sys as _sys
@@ -2541,11 +2541,29 @@ def _get_value(self, action, arg_string):
         return result
 
     def _check_value(self, action, value):
+        if not action.choices and isinstance(action.choices, list):
+            msg = 'Either add options in choices array or remove it'
+            raise ArgumentError(action, msg)
+
         # converted value must be one of the choices (if specified)
         if action.choices is not None and value not in action.choices:
-            args = {'value': value,
-                    'choices': ', '.join(map(repr, action.choices))}
-            msg = _('invalid choice: %(value)r (choose from %(choices)s)')
+            try:
+                closest_choice = _difflib.get_close_matches(value, action.choices, 1)
+            except TypeError:
+                closest_choice = []
+
+            args = {
+                'value': value,
+                'choices': ', '.join(map(repr, action.choices)),
+            }
+            if closest_choice:
+                closest_choice = closest_choice[0]
+                args['closest'] = closest_choice
+                msg = _('invalid choice: %(value)r, maybe you meant %(closest)r? '
+                        '(choose from %(choices)s)')
+            else:
+                msg = _('invalid choice: %(value)r (choose from %(choices)s)')
+
             raise ArgumentError(action, msg % args)
 
     # =======================

Lib/test/test_argparse.py

@@ -2193,9 +2193,9 @@ def test_wrong_argument_subparsers_no_destination_error(self):
         subparsers.add_parser('bar')
         with self.assertRaises(ArgumentParserError) as excinfo:
             parser.parse_args(('baz',))
-        self.assertRegex(
+        self.assertIn(
+            "error: argument {foo,bar}: invalid choice: 'baz', maybe you meant 'bar'? (choose from 'foo', 'bar')",
             excinfo.exception.stderr,
-            r"error: argument {foo,bar}: invalid choice: 'baz' \(choose from 'foo', 'bar'\)\n$"
         )
 
     def test_optional_subparsers(self):

Misc/NEWS.d/next/Core and Builtins/2022-11-25-12-23-56.gh-issue-99749.-S_guS.rst

@@ -0,0 +1 @@
+Add closest choice if exists in Argparser if wrong choice picked.