argparse: use str() consistently and explicitly to print choices

Fixes: python#86357

Signed-off-by: Jan Chren ~rindeal <dev.rindeal@gmail.com>

Lib/argparse.py

@@ -548,8 +548,7 @@ def _metavar_formatter(self, action, default_metavar):
         if action.metavar is not None:
             result = action.metavar
         elif action.choices is not None:
-            choice_strs = [str(choice) for choice in action.choices]
-            result = '{%s}' % ','.join(choice_strs)
+            result = '{%s}' % ','.join(map(str, action.choices))
         else:
             result = default_metavar
 
@@ -597,8 +596,7 @@ def _expand_help(self, action):
             if hasattr(params[name], '__name__'):
                 params[name] = params[name].__name__
         if params.get('choices') is not None:
-            choices_str = ', '.join([str(c) for c in params['choices']])
-            params['choices'] = choices_str
+            params['choices'] = ', '.join(map(str, params['choices']))
         return self._get_help_string(action) % params
 
     def _iter_indented_subactions(self, action):
@@ -707,7 +705,7 @@ def _get_action_name(argument):
     elif argument.dest not in (None, SUPPRESS):
         return argument.dest
     elif argument.choices:
-        return '{' + ','.join(argument.choices) + '}'
+        return '{%s}' % ','.join(map(str, argument.choices))
     else:
         return None
 
@@ -2556,8 +2554,8 @@ def _check_value(self, action, value):
         # 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)')
+                    'choices': ', '.join(map(str, action.choices))}
+            msg = _('invalid choice: %(value)s (choose from %(choices)s)')
             raise ArgumentError(action, msg % args)
 
     # =======================

Lib/test/test_argparse.py

@@ -15,6 +15,7 @@
 import argparse
 import warnings
 
+from enum import StrEnum
 from test.support import os_helper, captured_stderr
 from unittest import mock
 
@@ -952,6 +953,35 @@ class TestDisallowLongAbbreviationAllowsShortGroupingPrefix(ParserTestCase):
     ]
 
 
+class TestStrEnumChoices(TestCase):
+    class Color(StrEnum):
+        RED = "red"
+        GREEN = "green"
+        BLUE = "blue"
+
+    def test_metavar_formatter_with_strenum(self):
+        parser = argparse.ArgumentParser()
+        parser.add_argument('--color', choices=self.Color)
+        args = parser.parse_args(['--color', 'red'])
+        self.assertEqual(args.color, self.Color.RED)
+
+    def test_expand_help_with_strenum(self):
+        parser = argparse.ArgumentParser()
+        parser.add_argument('--color', choices=self.Color, help='Choose a color')
+        help_output = parser.format_help()
+        self.assertIn('[--color {red,green,blue}]', help_output)
+        self.assertIn('  --color {red,green,blue}', help_output)
+
+    def test_check_value_with_strenum(self):
+        parser = argparse.ArgumentParser()
+        parser.add_argument('--color', choices=self.Color)
+        self.assertRaisesRegex(
+            argparse.ArgumentError,
+            "invalid choice: yellow \(choose from red, green, blue\)",
+            parser.parse_args,
+            ['--color', 'yellow'],
+        )
+
 # ================
 # Positional tests
 # ================
@@ -2399,7 +2429,7 @@ def test_wrong_argument_subparsers_no_destination_error(self):
             parser.parse_args(('baz',))
         self.assertRegex(
             excinfo.exception.stderr,
-            r"error: argument {foo,bar}: invalid choice: 'baz' \(choose from 'foo', 'bar'\)\n$"
+            r"error: argument {foo,bar}: invalid choice: baz \(choose from foo, bar\)\n$"
         )
 
     def test_optional_subparsers(self):
@@ -6061,7 +6091,7 @@ def test_subparser(self):
         args = parser.parse_args(['x', '--', 'run', '--', 'a', '--', 'b'])
         self.assertEqual(NS(foo='x', f=None, bar=['a', '--', 'b']), args)
         self.assertRaisesRegex(argparse.ArgumentError,
-            "invalid choice: '--'",
+            "invalid choice: --",
             parser.parse_args, ['--', 'x', '--', 'run', 'a', 'b'])
 
     def test_subparser_after_multiple_argument_option(self):
@@ -6075,7 +6105,7 @@ def test_subparser_after_multiple_argument_option(self):
         args = parser.parse_args(['--foo', 'x', 'y', '--', 'run', 'a', 'b', '-f', 'c'])
         self.assertEqual(NS(foo=['x', 'y'], f='c', bar=['a', 'b']), args)
         self.assertRaisesRegex(argparse.ArgumentError,
-            "invalid choice: '--'",
+            "invalid choice: --",
             parser.parse_args, ['--foo', 'x', '--', '--', 'run', 'a', 'b'])
 
 

Misc/NEWS.d/next/Library/2024-04-19-05-58-50.gh-issue-117766.J3xepp.rst

@@ -0,0 +1 @@
+Always use :func:`str` to print ``choices`` in :mod:`argparse`.