[3.11] pythongh-113358: Fix rendering tracebacks with exceptions with…

… a broken __getattr__ (pythonGH-113359)

(cherry picked from commit 04fabe2)

Co-authored-by: Jérome Perrin <perrinjerome@gmail.com>
Co-authored-by: Irit Katriel <1055913+iritkatriel@users.noreply.github.com>

Lib/test/test_traceback.py

@@ -1601,6 +1601,20 @@ def __repr__(self):
         err_msg = '<note str() failed>'
         self.assertEqual(self.get_report(e), vanilla + err_msg + '\nFinal Note\n')
 
+        # an exception with a broken __getattr__ raising a non expected error
+        class BrokenException(Exception):
+            broken = False
+            def __getattr__(self, name):
+                if self.broken:
+                    raise ValueError(f'no {name}')
+
+        e = BrokenException(123)
+        vanilla = self.get_report(e)
+        e.broken = True
+        self.assertEqual(
+            self.get_report(e),
+            vanilla + "Ignored error getting __notes__: ValueError('no __notes__')\n")
+
     def test_exception_with_multiple_notes(self):
         for e in [ValueError(42), SyntaxError('bad syntax')]:
             with self.subTest(e=e):

Lib/traceback.py

@@ -733,7 +733,11 @@ def __init__(self, exc_type, exc_value, exc_traceback, *, limit=None,
         # Capture now to permit freeing resources: only complication is in the
         # unofficial API _format_final_exc_line
         self._str = _safe_string(exc_value, 'exception')
-        self.__notes__ = getattr(exc_value, '__notes__', None)
+        try:
+            self.__notes__ = getattr(exc_value, '__notes__', None)
+        except Exception as e:
+            self.__notes__ = [
+                f'Ignored error getting __notes__: {_safe_string(e, "__notes__", repr)}']
 
         if exc_type and issubclass(exc_type, SyntaxError):
             # Handle SyntaxError's specially

Misc/NEWS.d/next/Library/2023-12-21-14-55-06.gh-issue-113358.nRkiSL.rst

@@ -0,0 +1 @@
+Fix rendering tracebacks with exceptions with a broken __getattr__