logging: don't define QueueListener if Python has no thread support

Lib/logging/handlers.py

@@ -27,7 +27,10 @@ To use, simply 'import logging.handlers' and log away!
 import logging, socket, os, pickle, struct, time, re
 from stat import ST_DEV, ST_INO, ST_MTIME
 import queue
-import threading
+try:
+    import threading
+except ImportError:
+    threading = None
 
 try:
     import codecs
@@ -1218,7 +1221,8 @@ class QueueHandler(logging.Handler):
         except:
             self.handleError(record)
 
-class QueueListener(object):
+if threading:
+    class QueueListener(object):
         """
         This class implements an internal threaded listener which watches for
         LogRecords being added to a queue, removes them and passes them to a

Lib/test/test_logging.py

@@ -2093,6 +2093,8 @@ class QueueHandlerTest(BaseTest):
         self.assertEqual(data.name, self.que_logger.name)
         self.assertEqual((data.msg, data.args), (msg, None))
 
+    @unittest.skipUnless(hasattr(logging.handlers, 'QueueListener'),
+                         'logging.handlers.QueueListener required for this test')
     def test_queue_listener(self):
         handler = TestHandler(Matcher())
         listener = logging.handlers.QueueListener(self.queue, handler)

Misc/NEWS

@@ -79,6 +79,8 @@ Core and Builtins
 Library
 -------
 
+- logging: don't define QueueListener if Python has no thread support.
+
 - Issue #11277: mmap.mmap() calls fcntl(fd, F_FULLFSYNC) on Mac OS X to get
   around a mmap bug with sparse files. Patch written by Steffen Daode Nurpmeso.