Overriding tie-configuration & \shape breaks custom Scheme function since 2.19.24

[Peter Crighton]

Hello,

I have a small Scheme function to make single note heads in a chord
smaller which used to work in the past. But now there’s a bug in it
when I override the tie-configuration or use the \shape function,
which makes all note heads in the chord smaller from that point
onwards.
As you can see in the example code below, the bug only appears when
the override is set in the part affected by the Scheme function \bgr.
If you comment that out and use the upper override, it works.
This behaviour appears since 2.19.24, before that my function used to
work regardless of where I put the override. Any ideas what causes
this and how to fix it?

Thanks,
Peter


\version "2.19.33"

bgr = #(define-music-function (parser location music) (ly:music?)
         (music-map (lambda (mus)
                      (if (or (music-is-of-type? mus 'rest-event)
                              (music-is-of-type? mus 'multi-measure-rest))
                          (make-music 'SkipEvent mus)
                          #{
                            \tweak NoteHead.font-size #-2
                            \tweak Accidental.font-size #-2
                            #mus
                          #}))
           music))


\new Staff <<
  \new Voice <<
    \relative c' {
      <<
        {
          c4 d e f~
          %\once \override TieColumn.tie-configuration = #'((0 . 1) (0 . -1))
          f g a b
        }

        \bgr {
          g a b c~
          \once \override TieColumn.tie-configuration = #'((0 . 1) (0 . -1))
          c d e f
        }
      >>
    }
  >>
>>


--
Peter Crighton | Musician & Music Engraver based in Mainz, Germany
http://www.petercrighton.de