commit 1a2189353f744f79a43511707c090c3807a4978e
author Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> Sat Oct 06 21:33:37 2018 -0700
committer Ned Deily <nad@python.org> Sun Oct 07 00:33:37 2018 -0400
tree eb6b401ac5fe7ebf029eb94295a913a29e30dad4
parent 4322b8dd0fa4a9d14a54a50e4aedf40777d9a029

bpo-34334: Don't log traceback twice in QueueHandler (GH-9537) (GH-9581)

(cherry picked from commit d345bb4d9b6e16c681cd8a4e1fff94ecd6b0bb09)

Co-authored-by: Cheryl Sabella <cheryl.sabella@gmail.com>

Lib/test/test_logging.py

diff --git a/Lib/test/test_logging.py b/Lib/test/test_logging.py
index 13f49f6..5d5eba7 100644
--- a/Lib/test/test_logging.py
+++ b/Lib/test/test_logging.py
@@ -3278,6 +3278,21 @@
         self.assertFalse(handler.matches(levelno=logging.WARNING, message='4'))
         self.assertFalse(handler.matches(levelno=logging.ERROR, message='5'))
         self.assertTrue(handler.matches(levelno=logging.CRITICAL, message='6'))
+        handler.close()
+
+    @unittest.skipUnless(hasattr(logging.handlers, 'QueueListener'),
+                         'logging.handlers.QueueListener required for this test')
+    def test_queue_listener_with_StreamHandler(self):
+        # Test that traceback only appends once (bpo-34334).
+        listener = logging.handlers.QueueListener(self.queue, self.root_hdlr)
+        listener.start()
+        try:
+            1 / 0
+        except ZeroDivisionError as e:
+            exc = e
+            self.que_logger.exception(self.next_message(), exc_info=exc)
+        listener.stop()
+        self.assertEqual(self.stream.getvalue().strip().count('Traceback'), 1)
 
 if hasattr(logging.handlers, 'QueueListener'):
     import multiprocessing