[MERGE] ``BZR_LOG=disable`` suppresses writing messages to .bzr.log.

[John Arbash Meinel]

Alexander Belchenko wrote:
> This patch adds support for BZR_LOG env variables that allows to 
> suppress .bzr.log.
> 

It seems to me that it should be done by the 'bzr' code, not inside the 
bzrlib code.

Specifically, inside 'bzr' we have:
if __name__ == '__main__':
     bzrlib.trace.enable_default_logging()
     exit_val = bzrlib.commands.main(sys.argv)

If someone is asking 'bzrlib' to enable the log, then I think we should 
be doing so.

So I would prefer something like:

if __name__ == '__main__':
   if os.environ.get('BZR_LOG', '').lower() != 'disable':
     bzrlib.trace.enable_default_logging()

As far as having it in a config file rather than in an environment 
variable... I understand the utility of it, but by the time we get to 
parsing config files, we've already started logging.

So we *could* do that, but it would be difficult to make it not log 
anything.

I'm also not a big fan of calling it "BZR_LOG=disable". I might prefer 
BZR_DISABLE_LOG=1
or
BZR_ENABLE_LOG=0

John
=:->