bug#74966: 31.0.50; Crash report (using igc on macOS)

[Eli Zaretskii]

> From: Gerd Möllmann <gerd.moellmann@gmail.com>
> Cc: Andrea Corallo <acorallo@gnu.org>,  pipcet@protonmail.com,
>   spd@toadstyle.org,  74966@debbugs.gnu.org
> Date: Fri, 20 Dec 2024 09:21:38 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> Cc: spd@toadstyle.org, 74966@debbugs.gnu.org
> >> From: Gerd Möllmann <gerd.moellmann@gmail.com>
> >> Date: Fri, 20 Dec 2024 08:30:55 +0100
> >> 
> >> Gerd Möllmann <gerd.moellmann@gmail.com> writes:
> >> 
> >> > I think I'll read the code a bit now.
> >> 
> >> BTW, does C-h f x-file-dialog work on platforms != macOS?
> >
> > In what version of Emacs? and with or without native compilation?
> 
> master with native compilation, if possible with --enable-checking.
> 
> >
> > It works here as follows:
> >
> >   . On MS-Windows:
> >     - emacs 31 without native compilation
> >     - emacs 30 with and without native compilation
> >   . On GNU/Linux:
> >     - emacs 31 with and without native compilation
> >     - emacs 30 with and without native compilation
> >
> >> It aborts here for the same reason.
> >> 
> >> And I'm asking myself now why the heck it lands in native_function_doc in
> >> the first place. Isn't x-file-dialog a C function everywhere?
> >
> > It is a C function, yes.
> 
> My current theory is that one needs to C-h f a function with a doc
> string lie this one:
> 
> (defun x-file-dialog (prompt dir &optional default-filename
>                              mustmatch only-dir-p)
>   "SKIP: real doc in xfns.c."
>   (ns-read-file-name prompt dir mustmatch default-filename only-dir-p))
> 
> And the function must be native-comp-function-p.
> 
> I can't see so far how/where such "redirections" are handled.

AFAIR, the doc string is in etc/DOC, and is collected by
lib-src/make-docfile.  That program scans the C source according to
what src/Makefile tells is (see the $(etc)/DOC rule there), so it
doesn't care whether xfns.c is or isn't compiled into the binary.

But we had many changes lately in how etc/DOC is handled, and maybe my
memory is no long accurate.  So I added Stefan to this discussion, who
made at least some of those DOC-related changes.