Re: Issue 1695 in lilypond: Clef change placed outside score

[lilypond]

Comment #4 on issue 1695 by address@hidden: Clef change placed outside  
score
http://code.google.com/p/lilypond/issues/detail?id=1695

1d4914c023a672e0e80b9b9eafc123605f4c0f00 is the first really bad commit (my  
initial commit is also a bit weird, but it's the tempo mark which is  
wrongly positioned in that case. :)

It looks like a Break_align_engraver problem: despite the MetronomeMark  
being aligned on a note, it's still acknowledged as a break-alignable  
object.  It gets a BreakAlignment as a temporary X-parent (until the  
Metronome_engraver changes it at the end of the timestep), which interferes  
with the loose column the clef's attached to.

I think we can use 'non-musical to prevent this: if it's set in  
Metronome_engraver when we're sure the MetronomeMark *is* non-musical  
(i.e., not positioned over a note or rest), it should be easy to filter out  
any mark which doesn't need the services of the Break_align_engraver.