poll: who really uses mutter?

[Martin Pool]

In general application debug logs are handy things.  But I'm not finding
mutter and .bzr.log super useful at the moment, on the crucial test of
"when something goes wrong, can you work it out just from the logs
messages already produced".  (One can probably make a theory about the
intersection of problem space, log setup, and typical bug where they do
work like that, but let's leave that for now.)

Getting .bzr.log (other than the traceback) rarely seems to add much to
bug reports.  (In 0.9 the tracback will just be printed when something
goes wrong.)  When I do add mutter calls they're typically useful for
tracking down one particular bug and not much after that, and having
them in the log is not so useful.  Many of the existing mutter() calls
produce noise without being very useful, particularly when they're shown
in test failures.

I suppose having them go to .bzr.log does have the advantage that it
doesn't pollute stderr if you're using it for something else.

I have a branch where I'm trying to clean up some of the trace code.  I
propose to 

 - prune or comment out some of the mutter calls that aren't helping
   much
 - not send them to .bzr.log by default?
 - perhaps add a -D option that writes to stderr - so they're more
   visible when debugging, and to make a pressure to remove useless
   traces

-- 
Martin