LilyPond - Repeat with Partial Measure at the End

Question

This demonstrates the problem:

\relative c' {
    c4 d e f
    d e
    \repeat volta 2 { 
        f g
        a, b c d
    }
    \alternative {
        {
            e2
        }
        {
            e2~ e2
        }
    }
}

And here's a picture:

I need the first ending to be half a measure, and the second ending to be a whole measure to work out musically. For a published example, see Idumea from the Sacred Harp. Though this is in 3/2, the idea is the same:

Apparently, LilyPond is treating the second ending as the second half the measure beginning in the first ending. I guess I don't expect LilyPond to have more sense than that; it would be a very subtle thing to get right, but how can I convince Lilypond to do the right thing here?

Answer 1

Well, this works:

\relative c' {
    c4 d e f
    d e
    \repeat volta 2 {
            f g
        a, b c d
    }
    \alternative {
        {
            e2
        }
        {
            \set Timing.measureLength = #(ly:make-moment 6/4)
            e2~ e2
        }
    }
}

(And of course, you can put that e2~ e2 back to e1.)