Re: Lilypond crash related to tuplets

[Aaron Hill]

On 2019-03-23 6:46 am, Andrew Bernard wrote:
> What calls calc_x_offset for Tuplet Number?

This likely may be coming from Scheme.  If you look at the Internals 
reference, you will see that the X-offset property for TupletNumber is 
by default set to ly:tuplet-number::calc-x-offset.

That means that if you were to call (ly:grob-property grob 'X-offset) 
against a TupletNumber, it will end up consulting the specified 
procedure which is in this case implemented in C++.

> Any assistance would be greatly appreciated. My string quartet is going
> nowhere but I am learning a lot about debugging lilypond.

Are you able to share your .ly that exhibits this behavior?  Without a 
failing case on my side, I am left to only guess what might be 
triggering the behavior.  That said, I have found a few things in the 
code that *could* be problematic.

For instance, would you try adding this to your project:

%%%%
  \override TupletBracket.X-positions = #(lambda (grob)
    (let ((xpos (ly:tuplet-bracket::calc-x-positions grob)))
      (if (> (car xpos) (cdr xpos))
        (format #t "\nwarning: Inverted X-positions ~a" xpos))
      (cons (min (car xpos) (cdr xpos)) (max (car xpos) (cdr xpos)))))
%%%%

This will emit a warning when it detects that the calculated X-positions 
are inverted, but it also patches the issue by making the interval 
valid.

-- Aaron Hill