Updated incorrect level-setting code to use setLevel(). (GH-16325)

Lib/logging/config.py

-# Copyright 2001-2016 by Vinay Sajip. All Rights Reserved.
+# Copyright 2001-2019 by Vinay Sajip. All Rights Reserved.
 #
 # Permission to use, copy, modify, and distribute this software and its
 # documentation for any purpose and without fee is hereby granted,
@@ -19,7 +19,7 @@ Configuration functions for the logging package for Python. The core package
 is based on PEP 282 and comments thereto in comp.lang.python, and influenced
 by Apache's log4j system.
 
-Copyright (C) 2001-2016 Vinay Sajip. All Rights Reserved.
+Copyright (C) 2001-2019 Vinay Sajip. All Rights Reserved.
 
 To use, simply 'import logging' and log away!
 """
@@ -173,9 +173,10 @@ def _handle_existing_loggers(existing, child_loggers, disable_existing):
     for log in existing:
         logger = root.manager.loggerDict[log]
         if log in child_loggers:
-            logger.level = logging.NOTSET
-            logger.handlers = []
-            logger.propagate = True
+            if not isinstance(logger, logging.PlaceHolder):
+                logger.setLevel(logging.NOTSET)
+                logger.handlers = []
+                logger.propagate = True
         else:
             logger.disabled = disable_existing
 

Lib/test/test_logging.py

@@ -4315,7 +4315,7 @@ class BasicConfigTest(unittest.TestCase):
         logging._handlers.clear()
         logging._handlers.update(self.saved_handlers)
         logging._handlerList[:] = self.saved_handler_list
-        logging.root.level = self.original_logging_level
+        logging.root.setLevel(self.original_logging_level)
 
     def test_no_kwargs(self):
         logging.basicConfig()