[luatex] \hyphenpenalty not working

[Élie Roux]

> There seems to be some interaction with \pretolerance.
>
> If you add \pretolerance=-10000, LuaTeX does break at the penalty.

Let me try to understand what's going on...

On http://www.tug.org/utilities/plain/cseq.html#pretolerance-rp it says 
that if you set pretolerance to a negative value (and indeed -1 is 
enough to get the expected result), TeX will skip its first attempt to 
build the paragraph without hyphenation.

This means that:

  * in pdfTeX, the first attempt results in breaking at the discretionary
    due to hyphenpenalty

  * in LuaTeX, the hyphenpenalty is not taken into account in the first
    attempt (which is the big difference), but if the first attempt is
    skipped with pretolerance=-1, then it's taken into account in the
    second attempt

Am I correct?

Would it be possible to make hyphenpenalty taken into account in the 
first attempt?

Thank you,
-- 
Elie