Intermittent core dumps with 2.25.8 under Ubuntu 22.04.3

[Trevor Bača]

Hi,

Moving from 2.25.7 to 2.25.8 causes intermittent core dumps under Ubuntu
22.04.3 when run on a score I've been maintaining through successive
versions of LilyPond.

The details here are a little tricky.

The score is divided into 14 separate LilyPond files.

When I build the score on my laptop (macOS, Ventura 13.5.2), LilyPond
2.25.8 interprets all 14 files perfectly; no core dumps.

But when I build the score on GitHub Actions (as a type of CI running on
old scores), LilyPond 2.25.8 core dumps while trying to interpret one
(randomly chosen!) file of the 14 input files. GitHub Actions declares
Ubuntu 22.04.3 as its operating system, and the LilyPond log at GitHub
looks like this:

Tue Sep 19 19:30:17 2023
Processing `/home/runner/work/dornen/dornen/dornen/sections/02/music.ly'
Parsing...
Interpreting music...Floating point exception (core dumped)

Now for the frustrating part:

I'm not sure how to further debug the problem, *because the file on which
2.25.8 core dumps appears to change every time GitHub Actions runs*. In the
example above, it was the input file for the 2nd section of the score that
core-dumped; on a previous run, it was section 8; and before that it was
section 9. Strangely, only 1 file ever seems to core dump per run.

Any advice on how to try to better report what's going on?

For obvious reasons, I can't bisect the .ly file down to a single offending
line. But FWIW my (completely blind) guess as to what's causing Lily to
core dump is one of these to things:

* grace notes
* multiplied note durations (used to create feather-beam style rhythms)

To be clear, I have absolutely no proof that that's what's going on. But
the music features these two types of input quite a bit, and in far distant
years I seem to remember one (or both?) of these things perhaps also
causing a core dump (on a much, much earlier version of the LilyPond). (And
perhaps the timing issues involved with grace notes would also make sense
with the floating point exception raised in the error message.)

Happy to try to help, if anyone can offer guidance on how to better report
the problem,

Trevor.

-- 
Trevor Bača
www.trevorbaca.com
soundcloud.com/trevorbaca