Subject: Re: [bug#73416] [PATCH core-updates] build: Set $0 to basename of command in `wrap-program'.

From: Liam Hupfer <[email-masked]>
Date: Mon, 21 Jul 2025 00:24:18 -0500

Liam Hupfer <[email-masked]> writes:

> I am not really advocating for reverting this. I don’t think Emacs
> should assume ‘argv[0]’ is correlated to the executable file name. I
> just want to write this down in proximity to the change that exposed it.
> I will probably report to Emacs since the C is relatively new.

I opened [bug#79064: native-lisp directory resolution shouldn’t depend on
Emacs filename resolution via argv[0]​].

On second thought, though, I think we should consider reverting the
change to ‘wrap-program’. [bug#73405: wrap-program should use the
basename of $0 as arg0] does not describe why ‘cling’ was segfaulting,
but I suspect it’s due to similar bad assumptions about argv[0] as the
Emacs issue.

I think wrappers should be as transparent as possible—however the user
invokes a command should be preserved in argv[0], whether using a
basename with PATH resolution or a relative or absolute filename. We
shouldn’t coerce argv[0] to a basename when the wrapper wasn’t called
that way. 99% of the time argv[0] is irrelevant, but the common case I’m
considering is programs that log how they were called—it’s disorienting
for the wrapper to affect that.

Maybe we can expose an argument to wrap-program to use the basename
approach, but IMO we should be handling the root cause in cases where
problems occur and pushing upstreams to handle arbitrary argv[0] values
robustly.

WDYT? Thanks!

—Liam

[bug#79064: native-lisp directory resolution shouldn’t depend on
Emacs filename resolution via argv[0]​] <https://yhetil.org/emacs/[email-masked]/>

[bug#73405: wrap-program should use the
basename of $0 as arg0] <https://yhetil.org/guix/[email-masked]/>