bug#23450: 24.5; Lossing DECCKM application sequences on "fg"

bug#23450: 24.5; Lossing DECCKM application sequences on "fg"

[Julien Palard]

Hi,

We noticed a bug, we're reproducing it like twice a week but we're still
unable to reproduce it explicitly, sorry for that.

Bug is: After sending emacs to the background with `C-z` and getting it
back with `fg`, sometimes, our terminal misses the
[DECCKM](http://www.vt100.net/docs/vt510-rm/DECCKM.html) flag.

We can easily fix it via `(send-string-to-terminal "\e[?1h")`, so we're
"sure" that this flag the "missing one", but we have no proof emacs is
faulty here.

It look like we're not alone:
http://stackoverflow.com/questions/4548106/screen-somehow-unmaps-my-arrow-keys-in-emacs-after-a-z/37032152

Here, we reproduced it with:

 - urxvt, putty, gnome term
 - emacs 24.5.1, emacs 24.4.1
 - GNU screen 4.02.01, 4.03.01, tmux 2.2
 - Debian GNU/Linux 8.4 (jessie)

Configured using:
 `configure --build x86_64-linux-gnu --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/lib
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes
 --enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.5/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.5/site-lisp:/usr/share/emacs/site-lisp
 --build x86_64-linux-gnu --prefix=/usr --sharedstatedir=/var/lib
 --libexecdir=/usr/lib --localstatedir=/var/lib
 --infodir=/usr/share/info --mandir=/usr/share/man --with-pop=yes
 --enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.5/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.5/site-lisp:/usr/share/emacs/site-lisp
 --with-x=no --without-gconf --without-gsettings 'CFLAGS=-g -O2
 -fstack-protector-strong -Wformat -Werror=format-security -Wall'
 CPPFLAGS=-D_FORTIFY_SOURCE=2 LDFLAGS=-Wl,-z,relro'

Important settings:
  value of $LC_ALL: en_US.utf8
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

     Minor modes in effect:
  global-company-mode: t
  company-mode: t
  global-flycheck-mode: t
  flycheck-mode: t
  icomplete-mode: t
  show-paren-mode: t
  tooltip-mode: t
  electric-indent-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
Quit
M-[ c is undefined [2 times]
M-[ d is undefined
M-[ c is undefined
Quit
call-interactively: Symbol's value as variable is void: Warning
M-[ d is undefined
M-[ c is undefined [2 times]
M-[ d is undefined
M-[ c is undefined

Load-path shadows:
/usr/share/emacs/24.5/site-lisp/debian-startup hides
/usr/share/emacs/site-lisp/debian-startup
/usr/share/emacs24/site-lisp/dictionaries-common/flyspell hides
/usr/share/emacs/24.5/lisp/textmodes/flyspell
/usr/share/emacs/site-lisp/rst hides
/usr/share/emacs/24.5/lisp/textmodes/rst
/usr/share/emacs24/site-lisp/dictionaries-common/ispell hides
/usr/share/emacs/24.5/lisp/textmodes/ispell




Features:
(shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util
help-fns mail-prsvr mail-utils windmove mule-util xterm warnings
company-files company-oddmuse company-keywords company-gtags
company-dabbrev-code company-dabbrev company-capf company-cmake
company-ropemacs company-xcode company-clang company-semantic
company-eclim company-template company-css company-nxml company-bbdb
company-jedi jedi-core python-environment epc ctable concurrent deferred
company-etags etags ring company solarized-theme solarized-definitions
flycheck regexp-opt find-func help-mode rx subr-x seq dash icomplete
info tool-bar easymenu cl-macs package epg-config time-date paren
footnote edmacro kmacro cl gv cl-loaddefs cl-lib tooltip electric
uniquify ediff-hook vc-hooks lisp-float-type tabulated-list newcomment
lisp-mode prog-mode register page menu-bar rfn-eshadow timer select
mouse jit-lock font-lock syntax facemenu font-core frame cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev
minibuffer 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 make-network-process
dbusbind gfilenotify multi-tty emacs)

Memory information:
((conses 16 170938 7052)
 (symbols 48 24321 1)
 (miscs 40 47 144)
 (strings 32 34351 4678)
 (string-bytes 1 910734)
 (vectors 16 15367)
 (vector-slots 8 408448 2523)
 (floats 8 86 337)
 (intervals 56 250 123)
 (buffers 960 12)
 (heap 1024 23206 943))

-- 
Julien Palard
http://mdk.fr

bug#23450: 24.5; Lossing DECCKM application sequences on "fg"

[Stefan Kangas]

Julien Palard <julien@palard.fr> writes:

> We noticed a bug, we're reproducing it like twice a week but we're still
> unable to reproduce it explicitly, sorry for that.
>
> Bug is: After sending emacs to the background with `C-z` and getting it
> back with `fg`, sometimes, our terminal misses the
> [DECCKM](http://www.vt100.net/docs/vt510-rm/DECCKM.html) flag.
>
> We can easily fix it via `(send-string-to-terminal "\e[?1h")`, so we're
> "sure" that this flag the "missing one", but we have no proof emacs is
> faulty here.
>
> It look like we're not alone:
> http://stackoverflow.com/questions/4548106/screen-somehow-unmaps-my-arrow-keys-in-emacs-after-a-z/37032152
>
> Here, we reproduced it with:
>
>  - urxvt, putty, gnome term
>  - emacs 24.5.1, emacs 24.4.1
>  - GNU screen 4.02.01, 4.03.01, tmux 2.2
>  - Debian GNU/Linux 8.4 (jessie)

This sounds a lot like Bug#2772 which was recently closed as unreproducible:
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=2772

Maybe we'll have better luck here.  One good piece of information that
the old bug lacked is that this is not happening consistently.

Are you still seeing this problem in a more recent version of Emacs,
preferably the latest version 26.2?

If the answer is yes, Eli Zaretskii suggested the following in the
discussion about the old bug report:

> A termscript file with all the keyboard input starting from before the
> suspension, from a system where the problem can be reproduced, could
> give us some hints.  See open-termscript.

Could you please provide us with such a termscript file?

Thanks,
Stefan Kangas

bug#23450: 24.5; Lossing DECCKM application sequences on "fg"

[Julien Palard via Bug reports for GNU Emacs, the Swiss army knife of text editors]

> Are you still seeing this problem in a more recent version of Emacs,
> preferably the latest version 26.2?

No, I stopped using GNU Screen a long time ago, so no fresh reproduction of this issue, sry.

-- 
Julien Palard
https://mdk.fr

bug#23450: 24.5; Lossing DECCKM application sequences on "fg"

[Stefan Kangas]

tags 23450 + unreproducible
close 23450
thanks

Julien Palard <julien@palard.fr> writes:

>> Are you still seeing this problem in a more recent version of Emacs,
>> preferably the latest version 26.2?
>
> No, I stopped using GNU Screen a long time ago, so no fresh reproduction of this issue, sry.

Thanks.  Since it's unlikely that we'll make any progress here without
a way to reproduce the bug, I'm closing this bug as unreproducible.

Best regards,
Stefan Kangas