bug#66546: 30.0.50; save-buffer to write-protected file without backup fails

[Eli Zaretskii]

> From: Jens Schmidt <jschmidt4gnu@vodafonemail.de>
> Cc: 66546@debbugs.gnu.org
> Date: Sun, 15 Oct 2023 11:34:17 +0200
> 
> Now the Emacs 29 code.  We simplify that in the assumption, that the
> extended attribute calls always succeed, and that we do not need the
> regular calls:
> 
>   (setq setmodes (list (file-extended-attributes buffer-file-name)
>                        buffer-file-name))
>   (set-file-extended-attributes buffer-file-name
>                                 (nth 0 setmodes))
> 
> The pseudo-code here looks like this:
> 
>   setmodes = file-extended-attributes (buffer-file-name);
>   set-file-extended-attributes (setmodes);

That's not what the code does, since it does call

   (set-file-modes buffer-file-name (logior (car setmodes) 128))

But I think I can guess what you wanted to say: you wanted to say that
set-file-modes is called _only_ if set-file-extended-attributes fails,
and it doesn't fail in this scenario.  Is that what you wanted to say?