bug#30461: 27.0.50; Incorrect description of sentinels

bug#30461: 27.0.50; Incorrect description of sentinels

[p.stephani2]

The manual says:

> A =E2=80=9Cprocess sentinel=E2=80=9D is a function that is called wheneve=
r the
> associated process changes status for any reason, including signals
> (whether sent by Emacs or caused by the process=E2=80=99s own actions) th=
at
> terminate, stop, or continue the process.

But that doesn't seem to be the case:

(let ((p (make-process :name "sleep"
		       :command '("sleep" "1h")
		       :sentinel (lambda (p s)
				   (message "sentinel: %S" s)))))
   (sit-for 0.1)
   (stop-process p)
   (sit-for 0.1)
   (continue-process p))

If you then check the messages buffer, you see only the following:

> sentinel: "run"

That is, the sentinel isn't called when the process is stopped or
continued.  However, the sentinel *is* called when manually sending a
STOP signal to the process.

Furthermore, the description about the possible event strings doesn't
mention "run".


In GNU Emacs 27.0.50 (build 13, x86_64-pc-linux-gnu, GTK+ Version 3.22.24)
  of 2018-02-14 built on localhost
Repository revision: 298275c595f6ca9e77f8131d34dda2b58fe1faa5
Windowing system distributor 'The X.Org Foundation', version 11.0.11903000
System Description: Debian GNU/Linux buster/sid

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Configured using:
  'configure --without-threads --enable-gcc-warnings=3Dwarn-only
  --enable-gtk-deprecation-warnings --without-pop --with-mailutils
  --enable-checking --enable-check-lisp-object-type --with-modules
  'CFLAGS=3D-O0 -ggdb3''

Configured features:
XPM JPEG TIFF GIF PNG SOUND DBUS GSETTINGS NOTIFY GNUTLS FREETYPE XFT
ZLIB TOOLKIT_SCROLL_BARS GTK3 X11 MODULES JSON

Important settings:
   value of $LANG: en_US.UTF-8
   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 seq byte-opt gv
bytecomp byte-compile cconv cl-loaddefs cl-lib dired dired-loaddefs
format-spec rfc822 mml easymenu mml-sec password-cache epa derived epg
epg-config gnus-util rmail rmail-loaddefs mm-decode mm-bodies mm-encode
mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047
rfc2045 ietf-drums mm-util mail-prsvr mail-utils elec-pair time-date
mule-util 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 menu-bar
rfn-eshadow isearch timer select scroll-bar mouse jit-lock font-lock
syntax facemenu font-core term/tty-colors frame 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 minibuffer
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 dbusbind inotify
dynamic-setting system-font-setting font-render-setting move-toolbar gtk
x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 95233 8069)
  (symbols 48 20245 1)
  (miscs 40 40 121)
  (strings 32 28327 2177)
  (string-bytes 1 757222)
  (vectors 16 14136)
  (vector-slots 8 499270 14020)
  (floats 8 50 67)
  (intervals 56 223 0)
  (buffers 992 12))

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bug#30461: 27.0.50; Incorrect description of sentinels

[Eli Zaretskii]

> Date: Wed, 14 Feb 2018 23:10:32 +0100
> From: p.stephani2@gmail.com
> 
> > A =E2=80=9Cprocess sentinel=E2=80=9D is a function that is called wheneve=
> r the
> > associated process changes status for any reason, including signals
> > (whether sent by Emacs or caused by the process=E2=80=99s own actions) th=
> at
> > terminate, stop, or continue the process.
> 
> But that doesn't seem to be the case:
> 
> (let ((p (make-process :name "sleep"
> 		       :command '("sleep" "1h")
> 		       :sentinel (lambda (p s)
> 				   (message "sentinel: %S" s)))))
>    (sit-for 0.1)
>    (stop-process p)
>    (sit-for 0.1)
>    (continue-process p))
> 
> If you then check the messages buffer, you see only the following:
> 
> > sentinel: "run"
> 
> That is, the sentinel isn't called when the process is stopped or
> continued.

I think the sentinel is in fact called when the process is continued:
that's where that "run" came from, right?  You will see in
process_send_signal that we explicitly call the sentinel when the
signal is SIGCONT.

> However, the sentinel *is* called when manually sending a STOP
> signal to the process.

Did you send SIGSTOP or SIGTSTP?  stop-process sends the latter.

> Furthermore, the description about the possible event strings doesn't
> mention "run".

The documentation describes the strings produced by status_message.
You will see that there's an "else" catch-all clause there that
produces the name of the status symbol it is passed as an argument, in
case it doesn't recognize it.  I believe that's where "run" comes from
(note that it has no final newline, unlike the documented event
strings).  We could add "run", but it should be clear that by the same
token the string could be _anything_, a name of any symbol which is
stashed in the process's status.

bug#30461: 27.0.50; Incorrect description of sentinels

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

>> That is, the sentinel isn't called when the process is stopped or
>> continued.
>
> I think the sentinel is in fact called when the process is continued:
> that's where that "run" came from, right?  You will see in
> process_send_signal that we explicitly call the sentinel when the
> signal is SIGCONT.

[...]

> The documentation describes the strings produced by status_message.
> You will see that there's an "else" catch-all clause there that
> produces the name of the status symbol it is passed as an argument, in
> case it doesn't recognize it.  I believe that's where "run" comes from
> (note that it has no final newline, unlike the documented event
> strings).

I've now added "run\n" to the list of example strings in the manual, and
also clarified that it's not an exhaustive list.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no