fix: Sort ENUM candidates by repr string to handle None correctly

ENUM(None, 'day', 'month', 'year') would crash sorted() because
Python 3 cannot compare str with None using '<'. Convert candidates
to repr strings before sorting to handle any type safely.

Co-authored-by: DeepSeek <service@deepseek.com>

Author: SilverRainZ

src/sphinxnotes/project/sphinxnotes_render_ext.py

@@ -41,7 +41,8 @@ def _fmt_type(t) -> str:
 
 def _format_autoconfval_types(valid_types) -> list[str]:
     if isinstance(valid_types, ENUM):
-        return [f'``{c!r}``' for c in sorted(valid_types._candidates)]  # pyright: ignore[reportPrivateUsage]
+        reprs = [repr(c) for c in valid_types._candidates]  # pyright: ignore[reportPrivateUsage]
+        return [f':py:`{r}`' for r in sorted(reprs)]
     return [f':py:`{_fmt_type(t)}`' for t in valid_types]
 
 

tests/test_render_ext.py

@@ -1,6 +1,9 @@
 """Tests for sphinxnotes_render_ext."""
 
-from sphinxnotes.project.sphinxnotes_render_ext import _fmt_type, _format_autoconfval_types
+from sphinxnotes.project.sphinxnotes_render_ext import (
+    _fmt_type,
+    _format_autoconfval_types,
+)
 from sphinx.config import ENUM
 
 
@@ -34,7 +37,11 @@ def test_union_type(self):
 class TestFormatAutoconfvalTypes:
     def test_enum(self):
         result = _format_autoconfval_types(ENUM('tab', 'grid'))
-        assert result == ["``'grid'``", "``'tab'``"]
+        assert result == [":py:`'grid'`", ":py:`'tab'`"]
+
+    def test_enum_with_none(self):
+        result = _format_autoconfval_types(ENUM(None, 'day', 'month', 'year'))
+        assert result == [":py:`'day'`", ":py:`'month'`", ":py:`'year'`", ':py:`None`']
 
     def test_simple_types(self):
         result = _format_autoconfval_types(frozenset({str, int}))