Re: Issue 1477 in lilypond: suppress output for expected warnings

[lilypond]

Comment #2 on issue 1477 by percival.music.ca: suppress output for expected  
warnings
http://code.google.com/p/lilypond/issues/detail?id=1477

For regtests:
- some people might do "make test" and think that something is wrong when  
they see 500+ lines of errors and warnings.
- the regtest comparison is quite verbose, and generally contains tons of  
false "warnings".  To quantify this, the last three regtest comparisons  
(.50, .49, and .48) contained  18 useless and 3 useful text diffs (4vs1,  
6vs1, 8vs1 respectively).  Admittedly, those "useless diffs" are already  
reported in other issue numbers.

For docs:
- some people might do "make doc" and think that something is wrong then  
they see over 2000 lines of errors and warnings.


I think it would be nice if we could tell programmers and doc writers "if  
your patch produces an error message when compiling regtests (and maybe  
even docs), don't push it".  But clearly that's not possible if we already  
have so many warnings -- even if it would be technically possible (by  
keeping a complete log of the previous doc build and doing a diff?), I  
think it would be horribly unfair to new contributors to insist that their  
work prints no errors when the existing code-base prints so many errors  
already.