Re: snippet throws programming errors

[Keith OHara]

Cynthia Karl <pckarl <at> mac.com> writes:

> \score        {
>   \new Staff << \key c \major  \music >>
>   \layout {
>     \context { \Voice \consists "Ambitus_engraver" } 
>   }
> }
> 
> throws the following two programming errors:

"Programming errors" are intended to report conditions that a programmer
thinks cannot happen in correct operation of the program. But with a large 
program with large numbers of people working on it, what one programmer thinks 
is an obviously-wrong situation might be considered a harmless null-case by 
another programmer.

In this case, \key c\major is alone in its own voice with no notes, so the 
Ambitus_engraver for that voice creates an ambitus with no note-heads,
but the note-column engraver thinks that an ambitus with nothing in it
must be an error.

> Where can I find out what's happening here?
http://git.savannah.gnu.org/gitweb/?p=lilypond.git;a=blob;f=lily/note-column.cc

>  and is there a way to suppress these errors similar to the way that
> warnings can be suppressed.  

I don't think so. 
I would write
 \new Staff \new Voice << \key c \major  \music >>

so that LilyPond's right hand doesn't fret about the empty voice for which 
her left hand created an empty ambitus