[luatex] Bug in io.popen

[Deepak Jois]

On Fri, Oct 21, 2016 at 8:19 PM, Taco Hoekwater <taco at elvenkind.com> wrote:
> I am pretty sure that would have said:
>
>> $ luatex popen.tex
>> This is LuaTeX, Version 0.95.0 (TeX Live 2016)
>>  system commands enabled.
>
> if kpathsea’s texmf.cnf variable shell_escape was set to ’t’.
>
> In ‘restricted’ mode (that you appear to be running in), only a preset
> list of commands may be executed, these are stored in the kpathsea
> shell_escape_commands variable.

Fair enough. I actually have a more elaborate setup where I disable
kpse and set texconfig.shell_escape to 't' as the first two things in
a Lua file passed as an argument to the --lua flag. Replicating that
as a minimal working example might take a bit of effort.

However, why does this not work?

$ cat popen.lua
texconfig.kpse_init = false
texconfig.shell_escape = 't'
io.popen("ls"):read("*l")

$ ~/.ufy/luatex --lua=popen.lua  "\bye"
popen.lua:3: attempt to index a nil value