xorriso : FAILURE : Not a known command

[Thomas Schmitt]

Hi,

Jakub Jermar wrote:
> I was able to workaround this issue by dropping the test for scriptness
> of grub[2]-mkrescue:

This will not work with the intermediate form of the binary which
existed from november 2013 to may 2015 and went e.g. into Debian 8.
This program needs a "--" between its own options and the arguments
which it shall forward to xorriso's mkisofs emulation.


> The test seems to draw wrong conclusions at least on Fedora 25.

Leslie's local version of grub-mkrescue is obviously the modern released
one. It is not easy to distinguish it from the unreleased but nevertheless
widespread version.
Leslie confirms that this shell gesture
  strings /usr/bin/grub-mkrescue | grep '^--usage'
yields a match with his local binary. I can confirm that it yields no
match with the binary in Debian 8.

Another way to find out would be to do it like autotool's ./configure:
First run without "--" and retry with "--" if this fails.


> The concern here would be if "-follow default" has the same semantics as
> "-as mkisofs -f".

Good question.
Indeed the mkisofs emulation option -f triggers the native command
-follow "on".
(https://dev.lovelyhq.com/libburnia/libisoburn/raw/master/xorriso/emulators.c
 line 1101 in function Xorriso_genisofs_fused_options():
     ret= Xorriso_option_follow(xorriso, "on", 0);
)
-follow "default" is equivalent to not using mkisofs option -f.


But as developer of xorriso i would really, really advise not to hop
out of mkisofs emulation in order to perform a native xorriso command.
It would work but would also give future developers of Grub.pm something
to riddle.
I.e. omit "-- -as mkisofs" with script and modern binary version,
use "--" with the intermediate binary version.


Have a nice day :)

Thomas