From bc10ba21ee605c9727d447537119b7f89731f3a6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9rome=20Perrin?= <perrinjerome@gmail.com>
Date: Tue, 16 Jan 2024 18:49:24 +0900
Subject: [PATCH] gh-113358: Fix rendering tracebacks with exceptions with a
 broken __getattr__ (GH-113359)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

cherry picked from commit 04fabe22dd98b4d87f672254b743fbadd5206352

Adjusted for 3.11, because exception printing also happens in C
code. For simplicity, instead of including the repr of the exception
that happened during __getattr__, this just prints that an error
occured.

Co-authored-by: Jérome Perrin <perrinjerome@gmail.com>
Co-authored-by: Irit Katriel <1055913+iritkatriel@users.noreply.github.com>
---
 Lib/test/test_traceback.py                        | 15 +++++++++++++++
 Lib/traceback.py                                  |  5 ++++-
 ...2023-12-21-14-55-06.gh-issue-113358.nRkiSL.rst |  1 +
 Python/pythonrun.c                                |  6 +++++-
 4 files changed, 25 insertions(+), 2 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2023-12-21-14-55-06.gh-issue-113358.nRkiSL.rst

diff --git a/Lib/test/test_traceback.py b/Lib/test/test_traceback.py
index 2881a3489084a08..b81419c29243f29 100644
--- a/Lib/test/test_traceback.py
+++ b/Lib/test/test_traceback.py
@@ -1601,6 +1601,21 @@ 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}')
+                raise AttributeError(name)
+
+        e = BrokenException(123)
+        vanilla = self.get_report(e)
+        e.broken = True
+        self.assertEqual(
+            self.get_report(e),
+            vanilla + "Ignored error getting __notes__\n")
+
     def test_exception_with_multiple_notes(self):
         for e in [ValueError(42), SyntaxError('bad syntax')]:
             with self.subTest(e=e):
diff --git a/Lib/traceback.py b/Lib/traceback.py
index ea045e27610d4d5..92e517467d5c3b0 100644
--- a/Lib/traceback.py
+++ b/Lib/traceback.py
@@ -733,7 +733,10 @@ 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__ = ['Ignored error getting __notes__']
 
         if exc_type and issubclass(exc_type, SyntaxError):
             # Handle SyntaxError's specially
diff --git a/Misc/NEWS.d/next/Library/2023-12-21-14-55-06.gh-issue-113358.nRkiSL.rst b/Misc/NEWS.d/next/Library/2023-12-21-14-55-06.gh-issue-113358.nRkiSL.rst
new file mode 100644
index 000000000000000..76416553a231a0d
--- /dev/null
+++ b/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__
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index 91c2ad3a13d4327..6431c69bc5eb0a1 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -1219,7 +1219,11 @@ print_exception(struct exception_print_context *ctx, PyObject *value)
     /* grab the type and notes now because value can change below */
     PyObject *type = (PyObject *) Py_TYPE(value);
     if (_PyObject_LookupAttr(value, &_Py_ID(__notes__), &notes) < 0) {
-        goto error;
+        PyErr_Clear();
+        notes = Py_BuildValue("[s]", "Ignored error getting __notes__");
+        if (notes == NULL) {
+            goto error;
+        }
     }
 
     if (print_exception_file_and_line(ctx, &value) < 0) {