facebook/tornado — pull request #741 by schlamar (2013-04-18 09:49:24+00:00)
Title: Do not configure the root logger.

Calling `basicConfig` leaks to other custom defined logger, so this leads to undesirable behavior. For example in this code example log messages gets printed out twice:

logger = logging.getLogger('mylogger')
logger.addHandler(logging.StreamHandler(sys.stdout))

loop = ioloop.IOLoop.current()
loop._stopped = True
loop.start()
logger.info('Test')

This PR changes the check of handlers by adding only the basicConfig handlers to the Tornado loggers.