In working with the TeXLive 2017 pretest, we (the Gregorio developers)
came across what appears to be a bug in io.popen: it's passing the
statement `all commands are permitted` to the sh instance that it was
creating, resulting in an `all: command not found` error. After some
considerable testing (see conversation here:
https://github.com/gregorio-project/gregorio/issues/1362), we isolated
the problem to the `--shell-escape` switch. If the simple document
below is compiled *without* the switch, it is behaves as expected and is
able to retrieve the gregorio version number (gregorio is on the list of
commands permitted without shell-escape in texmf.cnf for TeXLive 2017).
When compiled with the switch, however, the error crops up and the
document reads `l is nil`.
```
\documentclass{article}
\begin{document}
\directlua{
f = io.popen('gregorio --version', 'r')
if f then
l = f:read('*l')
if l then
tex.print('got '..l)
else
tex.print('l is nil')
end
else
tex.print('f is nil')
end
}
\end{document}
```
Besides the original Ubuntu 16.04 system this was seen on, we've also
been able to confirm it on Gentoo, Mac 10.10 (Yosemite), and Windows 10
and so believe the problem to be platform independent.
--
✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝
Br. Samuel, OSB
St. Anselm’s Abbey
Washington, DC
(R. Padraic Springuel)
PAX ☧ ΧΡΙΣΤΟΣ
