gh-103895: Improve how invalid `Exception.__notes__` are displayed (#103897)

2 files changed, 16 insertions, 4 deletions

diff --git a/Lib/test/test_traceback.py b/Lib/test/test_traceback.py
index 5e2b353..19a2be8 100644
--- a/Lib/test/test_traceback.py
+++ b/Lib/test/test_traceback.py
@@ -1539,11 +1539,11 @@ class BaseExceptionReportingTests:
 
         e.__notes__ = BadThing()
         notes_repr = 'bad repr'
-        self.assertEqual(self.get_report(e), vanilla + notes_repr)
+        self.assertEqual(self.get_report(e), vanilla + notes_repr + '\n')
 
         e.__notes__ = Unprintable()
         err_msg = '<__notes__ repr() failed>'
-        self.assertEqual(self.get_report(e), vanilla + err_msg)
+        self.assertEqual(self.get_report(e), vanilla + err_msg + '\n')
 
         # non-string item in the __notes__ sequence
         e.__notes__  = [BadThing(), 'Final Note']
@@ -1555,6 +1555,14 @@ class BaseExceptionReportingTests:
         err_msg = '<note str() failed>'
         self.assertEqual(self.get_report(e), vanilla + err_msg + '\nFinal Note\n')
 
+        e.__notes__  = "please do not explode me"
+        err_msg = "'please do not explode me'"
+        self.assertEqual(self.get_report(e), vanilla + err_msg + '\n')
+
+        e.__notes__  = b"please do not show me as numbers"
+        err_msg = "b'please do not show me as numbers'"
+        self.assertEqual(self.get_report(e), vanilla + err_msg + '\n')
+
     def test_exception_with_note_with_multiple_notes(self):
         e = ValueError(42)
         vanilla = self.get_report(e)
diff --git a/Lib/traceback.py b/Lib/traceback.py
index 9e720ac..ba4a9ff 100644
--- a/Lib/traceback.py
+++ b/Lib/traceback.py
@@ -852,12 +852,16 @@ class TracebackException:
             yield _format_final_exc_line(stype, self._str)
         else:
             yield from self._format_syntax_error(stype)
-        if isinstance(self.__notes__, collections.abc.Sequence):
+
+        if (
+            isinstance(self.__notes__, collections.abc.Sequence)
+            and not isinstance(self.__notes__, (str, bytes))
+        ):
             for note in self.__notes__:
                 note = _safe_string(note, 'note')
                 yield from [l + '\n' for l in note.split('\n')]
         elif self.__notes__ is not None:
-            yield _safe_string(self.__notes__, '__notes__', func=repr)
+            yield "{}\n".format(_safe_string(self.__notes__, '__notes__', func=repr))
 
     def _format_syntax_error(self, stype):
         """Format SyntaxError exceptions (internal helper)."""