[luatex] \hyphenpenalty not working

[Élie Roux]

Dear all,

It seems that \hyphenpenalty is not working at all in LuaTeX. See the 
difference between the outputs of LuaTeX and pdfTeX on the following 
example:

\hyphenpenalty=-10000
ab\discretionary{-}{-}{-}cd
\bye

P.S.: I have reporter the issue on http://tracker.luatex.org/view.php?id=842

Thank you!
--
Elie