Tweak warning message for an edge case of default in markup (#154)

Author: hamdanal

CHANGELOG.md

@@ -14,7 +14,8 @@
 
 ### Fixes
 - [GH-152](https://github.com/hamdanal/rich-argparse/issues/152),
-  [PR-153](https://github.com/hamdanal/rich-argparse/pull/153)
+  [PR-153](https://github.com/hamdanal/rich-argparse/pull/153),
+  [PR-154](https://github.com/hamdanal/rich-argparse/pull/154)
   Fix `ValueError` when using `%(default)s` inside square brackets and `help_markup` is enabled.
 - [GH-141](https://github.com/hamdanal/rich-argparse/issues/141),
   [PR-142](https://github.com/hamdanal/rich-argparse/pull/142)

rich_argparse/_argparse.py

@@ -452,13 +452,14 @@ def _rich_expand_help(self, action: Action) -> r.Text:
                 import warnings
 
                 action_id = next(iter(action.option_strings), action.dest)
-                md = re.search(
-                    rf"\[([^\]]*{self._printf_style_pattern.pattern}[^\]]*)\]", help_string, re.X
-                )
-                repl = (
-                    repr(md.group(1))[1:-1]
-                    if md and md.group("mapping") == "default"
-                    else "default: %(default)s"
+                printf_pat = self._printf_style_pattern.pattern
+                repl = next(
+                    (
+                        repr(m.group(1))[1:-1]
+                        for m in re.finditer(rf"\[([^\]]*{printf_pat}[^\]]*)\]", help_string, re.X)
+                        if m.group("mapping") == "default"
+                    ),
+                    "default: %(default)s",  # pragma: >=3.9 cover # fails on Python 3.8!
                 )
                 msg = (
                     f"Failed to process default value in help string of argument {action_id!r}."

tests/test_argparse.py

@@ -1028,23 +1028,23 @@ def test_arg_default_in_markup():
         "--foo",
         default="def",
         help=(
-            "(default: %(default)r)[default wrong: %(default)r] text [default wrong: %(default)s]"
-            "(default: %(default)s) [link default wrong %(default)s] %(default)s"
+            "[%(type)r type](good: %(default)r)[bad: %(default)r] text [bad: %(default)s]"
+            "(good: %(default)s) [link bad %(default)s] %(default)s"
         ),
     )
     expected_help_text = """\
     Usage: PROG [-h] [--foo FOO]
 
     Optional Arguments:
       -h, --help  show this help message and exit
-      --foo FOO   (default: 'def') text (default: def) def
+      --foo FOO   [None type](good: 'def') text (good: def) def
     """
     with pytest.warns(
         UserWarning,
         match=re.escape(
             "Failed to process default value in help string of argument '--foo'.\n"
             "Hint: try disabling rich markup: `RichHelpFormatter.help_markup = False`\n"
-            "      or replace brackets by parenthesis: `[default wrong: %(default)r]` -> `(default wrong: %(default)r)`"
+            "      or replace brackets by parenthesis: `[bad: %(default)r]` -> `(bad: %(default)r)`"
         ),
     ):
         help_text = parser.format_help()