bug#45181: 27.1; exit status and emacs.service

[Tim Ruffing]

The current emacs.service file contains the line  
'ExecStop=/usr/bin/emacsclient --eval "(kill-emacs)"'

I think there are two minor issues with that line.

First, it's redundant. If this  line is removed, systemd will default
to sending SIGTERM and emacs will call kill-emacs on SIGTERM.

Second, I don't think this is really doing what is intended. Sure,
emacsclient is invoking kill-emacs but the systemd will later tell me
that emacs was not cleanly stopped. Here's sample output of "systemctl
--user status emacs" after "systemctl --user stop emacs". Note the
"failed (Result: exit-code)".

● emacs.service - Emacs text editor
     Loaded: loaded (/home/tim/.config/systemd/user/emacs.service;
enabled; vendor preset: enabled)
     Active: failed (Result: exit-code) since Fri 2020-12-11 15:10:53
CET; 19min ago
       Docs: info:emacs
             man:emacs(1)
             https://gnu.org/software/emacs/
    Process: 3523 ExecStart=/usr/bin/emacs --fg-daemon (code=exited,
status=15)
    Process: 4121 ExecStop=/usr/bin/emacsclient --eval (kill-emacs)
(code=exited, status=0/SUCCESS)
   Main PID: 3523 (code=exited, status=15)

The problem here is the exit code 15, which emacs will return *only* if
it has received SIGTERM. I believe what's happening here is that
emacsclient will call kill-emacs but not wait until the emacs server
has properly shut down. However, it's supposed to wait for the shutdown
as an "ExecStop" command according to "man systemd.service". So since
the process is still alive when emacsclient comes back, systemd will
still issue SIGTERM, making emacs return 15 (maybe after calling kill-
emacs again?!).

I verified that if I spawn the server manually and invoke
"/usr/bin/emacsclient --eval "(kill-emacs)"" manually, then the server
will exit with status 0.

I think the proper thing to do is 
 - remove the ExecStop line (it's at least redundant and confusing)
 - add SuccessExitStatus=15 (to tell systemd that 15 is fine)

Best,
Tim

In GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.22,
cairo version 1.17.3)
 of 2020-08-28 built on juergen
Windowing system distributor 'The X.Org Foundation', version
11.0.12099001
System Description: Arch Linux

Configured using:
 'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
 --localstatedir=/var --with-x-toolkit=gtk3 --with-xft --with-wide-int
 --with-modules --with-cairo --with-harfbuzz 'CFLAGS=-march=x86-64
 -mtune=generic -O2 -pipe -fno-plt' CPPFLAGS=-D_FORTIFY_SOURCE=2
 LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'

Configured features:
XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND GPM DBUS GSETTINGS GLIB NOTIFY
INOTIFY ACL GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS LIBSYSTEMD JSON
PDUMPER LCMS2 GMP

Important settings:
  value of $LC_COLLATE: de_DE.UTF-8
  value of $LC_CTYPE: de_DE.UTF-8
  value of $LC_MESSAGES: en_US.UTF-8
  value of $LC_MONETARY: de_DE.UTF-8
  value of $LC_NUMERIC: de_DE.UTF-8
  value of $LC_TIME: de_DE.UTF-8
  value of $LANG: en_US.utf8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
format-spec rfc822 mml easymenu mml-sec password-cache epa derived epg
epg-config gnus-util rmail rmail-loaddefs text-property-search time-
date
subr-x seq byte-opt gv bytecomp byte-compile cconv mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader cl-
loaddefs
cl-lib sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-
utils
tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type
mwheel term/x-win x-win term/common-win x-dnd tool-bar dnd fontset
image
regexp-opt fringe tabulated-list replace newcomment text-mode elisp-
mode
lisp-mode prog-mode register page tab-bar menu-bar rfn-eshadow isearch
timer select scroll-bar mouse jit-lock font-lock syntax facemenu
font-core term/tty-colors frame minibuffer cl-generic cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese eucjp-ms cp51932 hebrew greek romanian slovak czech european
ethiopic indian cyrillic chinese composite charscript charprop
case-table epa-hook jka-cmpr-hook help simple abbrev obarray
cl-preloaded nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote threads dbusbind
inotify lcms2 dynamic-setting system-font-setting font-render-setting
cairo move-toolbar gtk x-toolkit x multi-tty make-network-process
emacs)

Memory information:
((conses 16 45785 10306)
 (symbols 48 6004 1)
 (strings 32 15644 1809)
 (string-bytes 1 511947)
 (vectors 16 10258)
 (vector-slots 8 133231 10154)
 (floats 8 19 43)
 (intervals 56 206 0)
 (buffers 1000 11))