Re: [PATCH] A myriad of interrelated daemon-mode startup bugs

[Stefan Monnier <monnier@IRO.UMontreal.CA>]

> [Stefan Cc:ed because part of this is fixing lexical-binding fallout,
>  and as a way of saying thank you for fixing a bug of mine: here's a
>  fix for a bug of yours! :) ]

Actually, it's got nothing to do with lexical-binding, but is due to
a bug of mine in gv-define-simpler-setter which was fixed yesterday.

> --- lisp/desktop.el.orig	2012-11-13 16:36:38.833375966 +0000
> +++ lisp/desktop.el	2012-11-13 16:38:18.634889091 +0000
> @@ -627,6 +627,7 @@
>                     (and
>                      (or (memq desktop-save '(ask ask-if-new))
>                          (and exists (eq desktop-save 'ask-if-exists)))
> +                    (and (not noninteractive))
>                      (y-or-n-p "Save desktop? ")))))

No need for `and' here, but otherwise, that looks OK.  Tho maybe a better
fix is to make it so y-or-n-p just returns nil when there's no live
terminal.

> -      (cl-letf (((default-file-modes) ?\700)) (make-directory dir t))
> +      (make-directory dir t ?\700)

The cl-letf ends up doing the exact same thing, via dynamic scoping
(note how it's not a simple `let' and it doesn't bind a variable but
a "place").
I'm not completely opposed to adding a "modes" argument to
make-directory, but I'm not sure it's worth the trouble.

> -      (server-start)
> +      (condition-case err
> +	  (server-start)
> +	(error (message (error-message-string err))))
>        (if server-process
>  	  (daemon-initialized)
>  	(if (stringp dn)

I'm not sure I understand enough of what could/should happen.  E.g. how
does the above compare to using:

    (unwind-protect
        (server-start)
      (if server-process
          (daemon-initialized)
        (if (stringp dn)
        ...

> +	;; We must pretend to be noninteractive at this point to tell
> +	;; kill-emacs-hook functions that read input if interactive
> +	;; not to do so, since reads from stdin are shared with the
> +	;; parent.
> +	(let ((noninteractive t))
> +	    (kill-emacs 1)))))

Actually, `noninteractive' can sometimes interact with the user via
stdin/stdout.

> -	/* End of file in -batch run causes exit here.  */
> -	if (noninteractive)
> +	/* End of file in -batch run or before the daemon is
> +	   initialized causes exit here.  */
> +	if ((noninteractive) ||
> +	    (IS_DAEMON && !daemon_initialized))
>  	  Fkill_emacs (Qt);

How 'bout having a Lisp-exported variable that controls whether to call
kill-emacs here?  Then server.el could set this var (after successfully
starting the daemon) to prevent exit.

Also, maybe the right way to solve this is to think harder about what
noninteractive means and how to split it into several variables.
E.g. one meaning is "no input events", another is "I/O is via
stdin/stdout", and another we need is "there's no I/O available right
now".


        Stefan