Not exactly! I've modded my example and am getting interesting results. In my original music (far too long to show here) without the change to voltaSpannerDuration the 2nd time volta spanner stretches right over the repeat unfold (over several lines) without any error message.
My original had two nested repeat unfolds (I didn't put this into my snippet an I didn't think it would be relevant), so I've replicated the correct structure below. With the change to voltaSpannerDuration I get the desired effect but a warning message. Without it there's no error message but the 2nd time volta spanner spans 5 bars - to the end of the line. Which is different from what happens in my original music. I can try to provide a reduced version which displays the issue, but it'll probably take some time to work it out.
\relative c''
{
c1
\repeat volta 2 {
c d e f
}
\alternative {
{
g f e d
}
{
% \set Score.voltaSpannerDuration = #(ly:make-moment 4/4)
\repeat unfold 2 {
\repeat unfold 12 {g8 a} g f e d c d e f
}
}
}
b1 a g f e
}
}
}
-------------------------
Thursday, October 6, 2016, 7:09:35 PM, you wrote:
Wright> On Thu 06 Oct 2016 at 18:12:27 (+0100), Peter Toye wrote:
>> Mark and Kieren,
>> Of course! The reason I didn't spot it is that the alternative starts with a 16-bar section in a \repeat unfold 2, and that of course is a separate _expression_.
>> It looks like I'll have to do the unfolding manually - what a pain!
Wright> Why? \set Score.voltaSpannerDuration = #(ly:make-moment 4/4)
Wright> still works.