Re: [UX] real names exposed

[ludo@gnu.org (Ludovic Courtès)]

Eric Bavier <ericbavier@openmailbox.org> skribis:

> On 2016-08-31 18:11, Leo Famulari wrote:
>> On Wed, Aug 31, 2016 at 02:25:49PM -0400, Troy Sankey wrote:
>>> I understand why this happens:
>>>
>>>   % khal --help
>>>   Usage: .khal-real [OPTIONS] COMMAND [ARGS]...
>>>   [...]
>>>
>>> but I think it sorta sucks for user experience.  Just thought I'd
>>> point this
>>> out, and I was wondering if there were any ideas to address this.
>>>
>>> Specifically, argv[0] references the name of the "real" executable,
>>> rather than
>>> the guix wrapper.  This is almost always benign, but it looks ugly
>>> in help
>>> menus.
>>
>> I wonder if the Khal author (Christian) intends for users to rename the
>> executable. Otherwise, why use argv[0]? Is it some side-effect of a
>> documentation tool used by Khal?
>>
>> I would understand if khal and ikhal were the same executable, and
>> behavior was changed based on argv[0], but that's not the case.
>>
>> It does look ugly.
>
> It's not just khal.  Most other executables and scripts that reference
> argv[0] or $0 end up with the *=real string.
>
> In our wrapper scripts, we pass -a to exec, which is supposed to
> address this issue, but for some reason it seems ineffective.

‘exec -a’ works as advertised:

--8<---------------cut here---------------start------------->8---
$ sh -c 'exec -a FOO guile -c "(pk (command-line))"'

;;; (("FOO"))
--8<---------------cut here---------------end--------------->8---

Yet:

--8<---------------cut here---------------start------------->8---
$ sh -c 'exec -a FOO /gnu/store/6vmniz83k46l8jpry50wdvwxsncz1r5w-khal-0.7.0/bin/.khal-wrap-01  --version'
.khal-real, version 0.7.0
--8<---------------cut here---------------end--------------->8---

And in fact:

--8<---------------cut here---------------start------------->8---
$ cat > t.py
import sys
print(sys.argv[0])
$ sh -c 'exec -a FOO python3 t.py'
t.py
--8<---------------cut here---------------end--------------->8---

… even though argv[0] is initially correct:

--8<---------------cut here---------------start------------->8---
$ sh -c 'exec -a FOO python3 --help' | head -1
usage: FOO [option] ... [-c cmd | -m mod | file | -] [arg] ...
--8<---------------cut here---------------end--------------->8---

So somewhere, Python finds out the real name, but it doesn’t seem to be
via /proc/cmdline or anything like that, and I couldn’t find the exact
hack in the source.

Ideas?

I would really like to fix it in ‘core-updates’.

Ludo’.