#137 non letters in discretionar causing dropped nodes

[David Carlisle]

this was originally reported on stackexchange at

http://tex.stackexchange.com/questions/350210/letters-after-discretionary-disappear-seems-an-issue-of-package-fontspec

but a kern in the thrid argument of \discretionary makes following text be dropped.

In the following plain tex example cult is dropped in all but the last case.

\font\test="Latin Modern Roman:mapping=tex-text" at 12pt

\test

\hsize =2in \advance\hsize by 11pt

shelf{}ful shelf{}ful shelf\-ful di\discretionary{f-}{fi}{f\kern0ptfi}cult task

shelf{}ful shelf{}ful shelf\-ful di\discretionary{f-}{fi}{f\/fi}cult task

shelf{}ful shelf{}ful shelf\-ful di\discretionary{f-}{fi}{f{}fi}cult task

shelf{}ful shelf{}ful shelf\-ful di\discretionary{f-}{fi}{ffi}cult task

di\discretionary{f-}{fi}{ffi}cult task

\bye

[Jonathan Kew]

I believe this should be fixed by commit 6a6805694f5509fe1c08ef2669ec3f514bc1649d, just pushed to the repository. Testing appreciated!

[Enrico Gregorio]

Tested with TeX Live 2018/pretest, it seems to work.