[luatex] Luatex: \prevdepth is unset after \halign

[Petr Olsak]

Hello,

LuaTeX behaves differently than other TeX engines in the following 
situation. After \halign contributes the lines to the vertical list, the 
\prevdepth is not set. Example:

\catcode`\{=1 \catcode`\}=2 \catcode `\#=6
\font\f=cmr10 \f
\halign{#\cr g\cr}
\message{::: \the\prevdepth}
\end

This file is named prev.tex. Now you can try:

$ luatex -ini prev.tex
This is LuaTeX, Version beta-0.76.0-2013052800 (rev 4627)  (INITEX)
  restricted \write18 enabled.
(./prev.tex ::: -1000.0pt [0] )
Output written on prev.dvi (1 page, 184 bytes).
Transcript written on prev.log.

$ tex -ini prev.tex
This is TeX, Version 3.1415926 (TeX Live 2013) (INITEX)
(./prev.tex ::: 1.94444pt [0] )
Output written on prev.dvi (1 page, 180 bytes).
Transcript written on prev.log.

$ xetex -ini prev.tex
This is XeTeX, Version 3.1415926-2.5-0.9999.3 (TeX Live 2013) (INITEX)
  restricted \write18 enabled.
(./prev.tex ::: 1.94444pt [0] )
Output written on prev.pdf (1 page).
Transcript written on prev.log.

$ pdftex -ini prev.tex
This is pdfTeX, Version 3.1415926-2.5-1.40.14 (TeX Live 2013) (INITEX)
  restricted \write18 enabled.
(./prev.tex ::: 1.94444pt [0] )
Output written on prev.dvi (1 page, 180 bytes).
Transcript written on prev.log.

I mean that this is a bug in the LuaTeX code.

Best regards

Petr Olsak