bug#67429: 27.1; oddities with gdb-mode completion buffer

[Bruno Haible]

I did 'M-x gdb-mode', and am trying to make use of gdb's
symbol completion: enter part of the name of a symbol,
and press <TAB>. Inside Emacs, I'm encountering two
oddities:

1) There is a buffer with possible completions, that
   disappears after two seconds if I don't choose a
   completion.
   After this buffer disappears, my cursor is elsewhere.
   I need an extra mouse interaction or key presses in
   order to bring back the cursor, so that I can continue
   typing the symbol's name.

2) In some cases, the buffer does not disappear but stays
   on screen. Why does it disappear in some cases but not
   in others?

Find attached a video that shows both problems.


In GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.33, cairo 
version 1.16.0)
 of 2023-08-16, modified by Debian built on lcy02-amd64-041
Windowing system distributor 'The X.Org Foundation', version 11.0.12101004
System Description: Ubuntu 22.04.3 LTS

Recent messages:
Making completion list...
Complete, but not unique
Making completion list...
Mark set
Complete, but not unique
Making completion list...
Complete, but not unique
Making completion list...
Quit
Making completion list...

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 --enable-libsystemd --with-pop=yes
 
--enable-locallisppath=/etc/emacs:/usr/local/share/emacs/27.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/27.1/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --without-gconf --with-mailutils --build
 x86_64-linux-gnu --prefix=/usr --sharedstatedir=/var/lib
 --libexecdir=/usr/lib --localstatedir=/var/lib
 --infodir=/usr/share/info --mandir=/usr/share/man --enable-libsystemd
 --with-pop=yes
 
--enable-locallisppath=/etc/emacs:/usr/local/share/emacs/27.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/27.1/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --without-gconf --with-mailutils --with-cairo
 --with-x=yes --with-x-toolkit=gtk3 --with-toolkit-scroll-bars
 'CFLAGS=-g -O2
 -ffile-prefix-map=/build/emacs-WL9mhG/emacs-27.1+1=. -fstack-protector-strong
 -Wformat -Werror=format-security -Wall' 'CPPFLAGS=-Wdate-time
 -D_FORTIFY_SOURCE=2' 'LDFLAGS=-Wl,-Bsymbolic-functions -Wl,-z,relro''

Configured features:
XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND GPM DBUS GSETTINGS GLIB NOTIFY
INOTIFY ACL LIBSELINUX 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_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.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Debugger

Minor modes in effect:
  delete-selection-mode: t
  cua-mode: t
  tooltip-mode: t
  global-eldoc-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
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
/usr/share/emacs/site-lisp/llvm-13/llvm-mode hides 
/usr/share/emacs/site-lisp/llvm-14/llvm-mode
/usr/share/emacs/site-lisp/llvm-13/tablegen-mode hides 
/usr/share/emacs/site-lisp/llvm-14/tablegen-mode
/usr/share/emacs/site-lisp/llvm-13/emacs hides 
/usr/share/emacs/site-lisp/llvm-14/emacs
/usr/share/emacs/site-lisp/elpa/cmake-mode-3.22.1/cmake-mode-autoloads hides 
/usr/share/emacs/site-lisp/elpa-src/cmake-mode-3.22.1/cmake-mode-autoloads
/usr/share/emacs/site-lisp/elpa/cmake-mode-3.22.1/cmake-mode-pkg hides 
/usr/share/emacs/site-lisp/elpa-src/cmake-mode-3.22.1/cmake-mode-pkg
/usr/share/emacs/site-lisp/elpa/cmake-mode-3.22.1/cmake-mode hides 
/usr/share/emacs/site-lisp/elpa-src/cmake-mode-3.22.1/cmake-mode

Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
format-spec rfc822 mml mml-sec epa derived epg epg-config gnus-util
rmail rmail-loaddefs text-property-search mm-decode mm-bodies mm-encode
mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047
rfc2045 ietf-drums mm-util mail-prsvr mail-utils time-date vc-git
diff-mode cc-mode cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align
cc-engine cc-vars cc-defs gdb-mi bindat gud easy-mmode comint ansi-color
ring cus-edit cus-start cus-load wid-edit delsel cua-base finder-inf
package easymenu browse-url url-handlers url-parse auth-source cl-seq
eieio eieio-core cl-macs eieio-loaddefs password-cache json subr-x map
url-vars seq byte-opt gv bytecomp byte-compile cconv cl-loaddefs cl-lib
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 138606 9751)
 (symbols 48 13394 1)
 (strings 32 38612 1750)
 (string-bytes 1 1305512)
 (vectors 16 19984)
 (vector-slots 8 251918 11432)
 (floats 8 53 83)
 (intervals 56 1779 0)
 (buffers 1000 19))

emacs-gdb-mode-2023-11-24_09.51.36.webm
Description: video/webm