Re: Issue 1274 in lilypond: convert-ly does not warn about #'dash-period = #-1 for LyricHyphen

[lilypond]

Comment #2 on issue 1274 by n.puttock: convert-ly does not warn about  
#'dash-period = #-1 for LyricHyphen
http://code.google.com/p/lilypond/issues/detail?id=1274

This is a weird one, since it shouldn't work in 2.12.3: it has exactly the  
same code for ly:lyric-hyphen::print as 2.13.34.  There's a line in the  
code which changes 'dash-period if it's smaller than 'length, so negative  
amounts shouldn't make the line invisible (this really only applies to  
grobs which support line-interface, whereas LyricHyphen brews its own line  
via Lookup::round_filled_box ()).

> The format changed, but the convert-ly rule (as currently written) only  
> applies to Slur and Tie.

That convert rule is unrelated to this.  The one I added in 2.13.31 changed  
negative 'dash-period to #'style = #'none, but it doesn't apply to  
LyricHyphen (perhaps it should, but then we'd have to change the stencil  
callback to use line-interface code).