Issue 1240 in lilypond: Music overflows page: #'((space . N) (stretchability . 0)) and nothing more with spacings

[lilypond]

Status: Accepted
Owner: ----
Labels: Type-Defect Priority-Medium

New issue 1240 by brownian.box: Music overflows page: #'((space . N)  
(stretchability . 0)) and nothing more with spacings
http://code.google.com/p/lilypond/issues/detail?id=1240

% ------------------8< ----------------------------
\version "2.13.31"

\score {
  \context ChoirStaff <<
    \new Staff \with {
      \override VerticalAxisGroup #'next-staff-spacing =
        #'((space . 18) (stretchability . 0))
    } <<
      \new Voice {
        \repeat "unfold" 42 { c''4 c'' c'' c'' }
      }
    >>
    %
    \new Staff \with {
      \override VerticalAxisGroup #'next-staff-spacing =
      #'((space . 18) (stretchability . 0))
    } <<
      \new Voice {
        \repeat "unfold" 42 { c''4 c'' c'' c'' }
      }
    >>
    %
    \new Staff \with {
      \override VerticalAxisGroup #'next-staff-spacing =
      #'((space . 18) (stretchability . 0))
    } <<
      \new Voice {
        \clef "treble_8"
        \repeat "unfold" 42 { c'4 c' c' c' }
      }
    >>
    \new Staff <<
      \new Voice {
        \clef "bass"
        \repeat "unfold" 42 { c4 c c c }
      }
    >>
  >>
}
% ------------------8< ----------------------------

This leads to:
% ------------------8< ----------------------------
$ LANG=C lilypond test.ly
GNU LilyPond 2.13.31
Processing `./test.ly'
Parsing...
Interpreting music... [8][16][24][32][40]
Preprocessing graphical objects...
Finding the ideal number of pages...
Fitting music on 1 or 2 pages...
Drawing systems...
warning: couldn't fit music on page: overflow is 147.300236
Layout output to `test.ps'...
Converting to `./test.pdf'...
success: Compilation successfully completed
% ------------------8< ----------------------------

Most recent "affected" version is 2.13.21, i have not tested with earlier  
versions, sorry.

Overflow value, obviously, depends on music (180 for page 2 and 350 for  
page 3 in real score).

Actually 2.12 allows to specify 'minimum-Y-extent for staves, so in some  
sense this is a regression.

But "i'm unsure", so "set it to Medium".

Please, take a look and reassign labels, THANKS.