[Python-checkins] bpo-31234: test_threading: fix ref cycle (#3150) (#3152)

[Victor Stinner]

https://github.com/python/cpython/commit/b50e7683acac36ff16e6c6c2c32d9a15e46b5174
commit: b50e7683acac36ff16e6c6c2c32d9a15e46b5174
branch: 3.6
author: Victor Stinner <victor.stinner at gmail.com>
committer: GitHub <noreply at github.com>
date: 2017-08-19T02:32:54+02:00
summary:

bpo-31234: test_threading: fix ref cycle (#3150) (#3152)

test_bare_raise_in_brand_new_thread() now explicitly breaks a
reference cycle to not leak a dangling thread.
(cherry picked from commit 3d284c081fc3042036adfe1bf2ce92c34d743b0b)

files:
M Lib/test/test_threading.py

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 0db028864d2..162a72ea03f 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -1066,6 +1066,8 @@ def run(self):
         thread.join()
         self.assertIsNotNone(thread.exc)
         self.assertIsInstance(thread.exc, RuntimeError)
+        # explicitly break the reference cycle to not leak a dangling thread
+        thread.exc = None
 
 class TimerTests(BaseTestCase):