[NTG-context] [luatex-plain] disappearing math-on node

3 Apr 2014

      Hi,

This is a bug report based on the issue discussed at
https://github.com/lualatex/luaotfload/issues/212

\font\tenrm{file:lmroman10-regular.otf:mode=node;script=latn}\tenrm
\setbox0\vbox{%
  x\penalty-10000
  $a$x$a$
}
\unvbox0
\setbox0\lastbox
\unhbox0
\end

The plain tex code shown above fails with a lua error:
luatex-fonts-merged.lua:9616: attempt to index local 'current' (a nil value)

My guess is: as math-on (math-off too) is a "discardable" item after a
linebreak, the first math-on node has gone away. So the
math-on/math-off pair has become broken, by which the behavior of
"node.end_of_math" is confused.

Regards,
-- 
Dohyun Kim
Seoul, Republic of Korea