bpo-42848: remove recursion from TracebackException (GH-24158)

1 files changed, 25 insertions, 0 deletions

diff --git a/Lib/test/test_traceback.py b/Lib/test/test_traceback.py
index abb5762..07555a0 100644
--- a/Lib/test/test_traceback.py
+++ b/Lib/test/test_traceback.py
@@ -1148,6 +1148,31 @@ class TestTracebackException(unittest.TestCase):
         self.assertEqual(exc_info[0], exc.exc_type)
         self.assertEqual(str(exc_info[1]), str(exc))
 
+    def test_long_context_chain(self):
+        def f():
+            try:
+                1/0
+            except:
+                f()
+
+        try:
+            f()
+        except RecursionError:
+            exc_info = sys.exc_info()
+        else:
+            self.fail("Exception not raised")
+
+        te = traceback.TracebackException(*exc_info)
+        res = list(te.format())
+
+        # many ZeroDiv errors followed by the RecursionError
+        self.assertGreater(len(res), sys.getrecursionlimit())
+        self.assertGreater(
+            len([l for l in res if 'ZeroDivisionError:' in l]),
+            sys.getrecursionlimit() * 0.5)
+        self.assertIn(
+            "RecursionError: maximum recursion depth exceeded", res[-1])
+
     def test_no_refs_to_exception_and_traceback_objects(self):
         try:
             1/0