gh-132385: Fix instance error suggestions trigger potential exceptions in traceback (#132387)

Author: sobolevn

Lib/test/test_traceback.py

@@ -4555,6 +4555,28 @@ def foo(self):
         actual = self.get_suggestion(instance.foo)
         self.assertNotIn("self.blech", actual)
 
+    def test_unbound_local_error_with_side_effect(self):
+        # gh-132385
+        class A:
+            def __getattr__(self, key):
+                if key == 'foo':
+                    raise AttributeError('foo')
+                if key == 'spam':
+                    raise ValueError('spam')
+
+            def bar(self):
+                foo
+            def baz(self):
+                spam
+
+        suggestion = self.get_suggestion(A().bar)
+        self.assertNotIn('self.', suggestion)
+        self.assertIn("'foo'", suggestion)
+
+        suggestion = self.get_suggestion(A().baz)
+        self.assertNotIn('self.', suggestion)
+        self.assertIn("'spam'", suggestion)
+
     def test_unbound_local_error_does_not_match(self):
         def func():
             something = 3

Lib/traceback.py

@@ -1636,7 +1636,11 @@ def _compute_suggestion_error(exc_value, tb, wrong_name):
         # has the wrong name as attribute
         if 'self' in frame.f_locals:
             self = frame.f_locals['self']
-            if hasattr(self, wrong_name):
+            try:
+                has_wrong_name = hasattr(self, wrong_name)
+            except Exception:
+                has_wrong_name = False
+            if has_wrong_name:
                 return f"self.{wrong_name}"
 
     try:

Misc/NEWS.d/next/Library/2025-04-11-12-41-47.gh-issue-132385.86HoA7.rst

@@ -0,0 +1,2 @@
+Fix instance error suggestions trigger potential exceptions
+in :meth:`object.__getattr__` in :mod:`traceback`.