Issue 5192: Update log message formatting.

Allow logger object log message creation methods using ''.format method.

have:

logger_object.info('%s','lazy is better')
logger_object.debug('{0!s}'.format('wasted effort'))


want:

logger_object.debug('{0}','Lazy')


Work'rounds from pep282:

if log.isEnabledFor(logging.INFO):
            hamletStr = hamletDom.toxml()
            log.info(hamletStr)

or install custom Formatter.

I presume this is already on the back burner.


Incidentally, BufferingFormatter.format uses string += string instead of
''.join(list_of_strings).

Isn't there a backward compatibility problem? If a message format string
contains both "%s" and "{0}", how is logging supposed to know what to
use - a % b or a.format(b)?

The way to do it is a custom Formatter, as you've indicated.