bpo-36829: test_threading: Fix a ref cycle (GH-13752)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 8c8cc128b0513b6c04194de3852a93e2e445cd8b..6ac4ea9623de0d065d936fcbfb712ce792021104 100644 (file)
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -1140,7 +1140,11 @@ class ExceptHookTests(BaseTestCase):
                 raise ValueError("bug")
             except Exception as exc:
                 args = threading.ExceptHookArgs([*sys.exc_info(), None])
-                threading.excepthook(args)
+                try:
+                    threading.excepthook(args)
+                finally:
+                    # Explicitly break a reference cycle
+                    args = None
 
         stderr = stderr.getvalue().strip()
         self.assertIn(f'Exception in thread {threading.get_ident()}:\n', stderr)