bug#33490: 27.0.50; auto-save-visited-mode clears the echo area every time the save interval is hit

bug#33490: 27.0.50; auto-save-visited-mode clears the echo area every time the save interval is hit

[Terje Larsen]

M-x auto-save-visited-mode
M-: (message "%s" "hello")

... Wait 5 seconds ...

Now the message buffer gets cleared and you lose the message. This is
causing usability issues when using eldoc/reading some output message as
it continously gets cleared.

I would expect the `auto-save-visited' feature to not change the behaviour
of the Echo Area. If you compare this to the `auto-save-mode' which
outputs a message indicating a save, but restores the Echo Area after.

I have tracked down this to the `save-some-buffers' function or more
specifically the `map-y-or-n-p' function that it calls. In this function
there is a call to message like `(message "")`.


In GNU Emacs 27.0.50 (build 2, x86_64-apple-darwin18.0.0, NS appkit-1671.00 Version 10.14 (Build 18A391))
of 2018-11-07 built on C02V91MHHV2Q.local
Repository revision: 811d9291fcfb12d87bad277d4e8b25152129d73d
Windowing system distributor 'Apple', version 10.3.1671
System Description:  Mac OS X 10.14.1

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Auto-Save-Visited mode enabled
You can run the command ‘auto-save-visited-mode’ with M-x au-v RET
Auto-Save-Visited mode enabled
hello
"hello"
Making completion list... [2 times]

Configured using:
'configure --disable-dependency-tracking --disable-silent-rules
--enable-locallisppath=/usr/local/share/emacs/site-lisp
--infodir=/usr/local/Cellar/emacs/HEAD-811d929_1/share/info/emacs
--prefix=/usr/local/Cellar/emacs/HEAD-811d929_1 --with-gnutls
--without-x --with-xml2 --without-dbus --with-imagemagick --with-rsvg
--with-ns --disable-ns-self-contained'

Configured features:
RSVG IMAGEMAGICK GLIB NOTIFY KQUEUE ACL GNUTLS LIBXML2 ZLIB
TOOLKIT_SCROLL_BARS NS THREADS LCMS2 GMP

Important settings:
  value of $LC_ALL: en_US.UTF-8
  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
  auto-save-visited-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny seq byte-opt gv
bytecomp byte-compile cconv dired dired-loaddefs format-spec rfc822 mml
easymenu mml-sec password-cache epa derived epg epg-config gnus-util
rmail rmail-loaddefs time-date 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 cus-start
cus-load elec-pair tooltip eldoc electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel term/ns-win ns-win ucs-normalize mule-util
term/common-win 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 threads kqueue cocoa ns lcms2 multi-tty make-network-process
emacs)

Memory information:
((conses 16 211301 10028)
(symbols 48 20869 1)
(strings 32 30416 1948)
(string-bytes 1 793438)
(vectors 16 35289)
(vector-slots 8 725548 23404)
(floats 8 47 72)
(intervals 56 245 0)
(buffers 992 12))

bug#33490: 27.0.50; auto-save-visited-mode clears the echo area every time the save interval is hit

[Eli Zaretskii]

> From: Terje Larsen <terje.larsen@klarna.com>
> Date: Sat, 24 Nov 2018 12:56:19 +0100
> 
> M-x auto-save-visited-mode
> M-: (message "%s" "hello")
> 
> ... Wait 5 seconds ...
> 
> Now the message buffer gets cleared and you lose the message. This is
> causing usability issues when using eldoc/reading some output message as
> it continously gets cleared.
> 
> I would expect the `auto-save-visited' feature to not change the behaviour
> of the Echo Area. If you compare this to the `auto-save-mode' which
> outputs a message indicating a save, but restores the Echo Area after.
> 
> I have tracked down this to the `save-some-buffers' function or more
> specifically the `map-y-or-n-p' function that it calls. In this function
> there is a call to message like `(message "")`.

Right.  Does the patch below fix the problem?

diff --git a/lisp/emacs-lisp/map-ynp.el b/lisp/emacs-lisp/map-ynp.el
index 8260af5..93235bd 100644
--- a/lisp/emacs-lisp/map-ynp.el
+++ b/lisp/emacs-lisp/map-ynp.el
@@ -79,6 +79,7 @@ map-y-or-n-p
 
 Returns the number of actions taken."
   (let* ((actions 0)
+         (msg (current-message))
 	 user-keys mouse-event map prompt char elt def
 	 ;; Non-nil means we should use mouse menus to ask.
 	 use-menus
@@ -250,9 +251,10 @@ map-y-or-n-p
       (if delayed-switch-frame
 	  (setq unread-command-events
 		(cons delayed-switch-frame unread-command-events))))
-    ;; Clear the last prompt from the minibuffer.
+    ;; Clear the last prompt from the minibuffer, and restore the
+    ;; previous echo-area message, if any.
     (let ((message-log-max nil))
-      (message ""))
+      (message (or msg "")))
     ;; Return the number of actions that were taken.
     actions))
 

bug#33490: 27.0.50; auto-save-visited-mode clears the echo area every time the save interval is hit

[Terje Larsen]

[-- Attachment #1: Type: text/plain, Size: 2047 bytes --]

Thank you for the quick fix, that seems to solve the issue.
Applying this patch and repeating the same kind of testing procedure produced the expected result.

> On 24 Nov 2018, at 19:40, Eli Zaretskii <eliz@gnu.org> wrote:
> 
>> From: Terje Larsen <terje.larsen@klarna.com>
>> Date: Sat, 24 Nov 2018 12:56:19 +0100
>> 
>> M-x auto-save-visited-mode
>> M-: (message "%s" "hello")
>> 
>> ... Wait 5 seconds ...
>> 
>> Now the message buffer gets cleared and you lose the message. This is
>> causing usability issues when using eldoc/reading some output message as
>> it continously gets cleared.
>> 
>> I would expect the `auto-save-visited' feature to not change the behaviour
>> of the Echo Area. If you compare this to the `auto-save-mode' which
>> outputs a message indicating a save, but restores the Echo Area after.
>> 
>> I have tracked down this to the `save-some-buffers' function or more
>> specifically the `map-y-or-n-p' function that it calls. In this function
>> there is a call to message like `(message "")`.
> 
> Right.  Does the patch below fix the problem?
> 
> diff --git a/lisp/emacs-lisp/map-ynp.el b/lisp/emacs-lisp/map-ynp.el
> index 8260af5..93235bd 100644
> --- a/lisp/emacs-lisp/map-ynp.el
> +++ b/lisp/emacs-lisp/map-ynp.el
> @@ -79,6 +79,7 @@ map-y-or-n-p
> 
> Returns the number of actions taken."
>   (let* ((actions 0)
> +         (msg (current-message))
> 	 user-keys mouse-event map prompt char elt def
> 	 ;; Non-nil means we should use mouse menus to ask.
> 	 use-menus
> @@ -250,9 +251,10 @@ map-y-or-n-p
>       (if delayed-switch-frame
> 	  (setq unread-command-events
> 		(cons delayed-switch-frame unread-command-events))))
> -    ;; Clear the last prompt from the minibuffer.
> +    ;; Clear the last prompt from the minibuffer, and restore the
> +    ;; previous echo-area message, if any.
>     (let ((message-log-max nil))
> -      (message ""))
> +      (message (or msg "")))
>     ;; Return the number of actions that were taken.
>     actions))


[-- Attachment #2: Type: text/html, Size: 23532 bytes --]

bug#33490: 27.0.50; auto-save-visited-mode clears the echo area every time the save interval is hit

[Eli Zaretskii]

> From: Terje Larsen <terje.larsen@klarna.com>
> Date: Sat, 24 Nov 2018 21:26:06 +0100
> 
> Thank you for the quick fix, that seems to solve the issue.
> Applying this patch and repeating the same kind of testing procedure produced the expected result.

Thanks, pushed to the emacs-26 branch.