[NTG-context] New tabulate features broken under new maths release

[Bruce Horrocks]

Hi Hans,

A few months back you announced some new tabulate features and gave some examples, from which I have taken the following MWE:

\starttext
\starttabulate[|lG{}|lG{}|]
\NC \showglyphs \setalignmentcharacter{=}111=111 \NC \setalignmentcharacter{=}111=111 \NC\NR
\stoptabulate
\stoptext


This works under "ConTeXt  ver: 2022.01.10 08:36 LMTX  fmt: 2022.1.13  int: english/english" but fails to compile under "ConTeXt  ver: 2022.07.06 21:42 LMTX  fmt: 2022.7.9  int: english/english" with the Lua error:

	callback error: ...-64/tex/texmf-context/tex/context/base/mkxl/node-ali.lmt:366: attempt to index a nil value (field '?')
stack traceback:
	...-64/tex/texmf-context/tex/context/base/mkxl/node-ali.lmt:366: in upvalue 'openup'
	...-64/tex/texmf-context/tex/context/base/mkxl/node-ali.lmt:596: in upvalue 'third_pass'
	...-64/tex/texmf-context/tex/context/base/mkxl/node-ali.lmt:613: in upvalue 'nodes_handlers_fixmathalign'
	[string "local tonut  = nodes.tonut..."]:17: in function <[string "local tonut  = nodes.tonut..."]:8>
	(...tail calls...)
	...-64/tex/texmf-context/tex/context/base/mkxl/node-pro.lmt:148: in function <...-64/tex/texmf-context/tex/context/base/mkxl/node-pro.lmt:146>	

Narrowing it down a bit, it seems to be the use of G{} as the MWE works with a plain \starttabulate[|l|l|] on the latest ConTeXt.

—
Bruce Horrocks
Hampshire, UK