bug#68799: 30.0.50; emacs --fg-daemon fails silently if server-start fails

[Eli Zaretskii <eliz@gnu.org>]

> From: Spencer Baugh <sbaugh@janestreet.com>
> Cc: 68799@debbugs.gnu.org
> Date: Mon, 29 Jan 2024 15:28:47 -0500
> 
> >> --- a/lisp/startup.el
> >> +++ b/lisp/startup.el
> >> @@ -1627,7 +1627,11 @@ command-line
> >>    (let ((dn (daemonp)))
> >>      (when dn
> >>        (when (stringp dn) (setq server-name dn))
> >> -      (server-start)
> >> +      (condition-case err
> >> +          (server-start)
> >> +        (error
> >> +         (message "%s" (error-message-string err))
> >> +         (kill-emacs 1)))
> >
> > Thanks, this needs a comment explaining why we need condition-case and
> > where does error-message-string come from.
> 
> Actually, on second thought, we could fail anywhere in startup.el, not
> just in server-start.  So should we actually have a wrapper around all
> of normal-top-level which detects an error at startup in a daemon?

I'd prefer to handle each specific problem specially, to make sure the
error message is self-explanatory.  Also, if the error happens after
the server has been started, there's no reason to forcibly exit.

So I think we should for now solve this particular issue, and not try
generalizing too much.