Subject: bug#76404: 31.0.50; ERC 5.6.1-git: new erc query buffer becomes sole window on RET

From: Trevor Arjeski <[email-masked]>
Date: Tue, 18 Feb 2025 23:27:58 +0300

Using a few new emacs 31 window configurations, upon creating a new erc
query buffer with `/query yournick`, hitting RET or sending a message
makes the window the sole window in the frame as if C-x 1 was entered.

Minimal reproduction:

(use-package window
  :custom
  (kill-buffer-quit-windows t)
  (quit-restore-window-no-switch 'skip-first))

1. Start erc
2. Open a query from the server buffer with `/query trev`
3. Hit enter
4. Notice that the query buffer that was created as a split becomes the
only window in the frame.

This seems to trigger in `erc--split-line` in erc-backend.el, where a
temp buffer is created and then subsequently killed.

In GNU Emacs 31.0.50 (build 10, x86_64-pc-linux-gnu, GTK+ Version
 3.24.48, cairo version 1.18.2) of 2025-02-14 built on trevarch
Repository revision: 4d6f40dfc9075d64275da97dc35a2becc9eca4a2
Repository branch: makepkg
System Description: Arch Linux

Configured using:
 'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
 --localstatedir=/var --mandir=/usr/share/man --with-gameuser=:games
 --with-modules --without-m17n-flt --without-gconf
 --with-native-compilation=yes --with-xinput2 --with-pgtk
 --without-xaw3d --with-sound=no --with-tree-sitter --without-gpm
 --without-compress-install
 '--program-transform-name=s/\([ec]tags\)/\1.emacs/'
 'CFLAGS=-march=x86-64 -mtune=generic -O2 -pipe -fno-plt -fexceptions
 -Wp,-D_FORTIFY_SOURCE=3 -Wformat -Werror=format-security
 -fstack-clash-protection -fcf-protection -fno-omit-frame-pointer
 -mno-omit-leaf-frame-pointer -Wno-implicit-function-declaration -g
 -ffile-prefix-map=/home/trev/Workspace/emacs-git/src=/usr/src/debug/emacs-git
 -flto=auto' 'LDFLAGS=-Wl,-O1 -Wl,--sort-common -Wl,--as-needed
 -Wl,-z,relro -Wl,-z,now -Wl,-z,pack-relative-relocs -flto=auto''

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG
LCMS2 LIBOTF LIBSYSTEMD LIBXML2 MODULES NATIVE_COMP NOTIFY INOTIFY
PDUMPER PGTK PNG RSVG SECCOMP SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS
TREE_SITTER WEBP XIM GTK3 ZLIB

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

Major mode: ELisp/l

Minor modes in effect:
  erc-track-mode: t
  erc-track-minor-mode: t
  erc-spelling-mode: t
  erc-ring-mode: t
  erc-netsplit-mode: t
  erc-menu-mode: t
  erc-match-mode: t
  erc-list-mode: t
  erc-irccontrols-mode: t
  erc-move-to-prompt-mode: t
  erc-readonly-mode: t
  erc-scrolltobottom-mode: t
  erc-imenu-mode: t
  erc-pcomplete-mode: t
  erc-button-mode: t
  erc-fill-mode: t
  erc-stamp-mode: t
  erc-autojoin-mode: t
  erc-networks-mode: t
  diff-hl-flydiff-mode: t
  global-diff-hl-mode: t
  diff-hl-mode: t
  paredit-mode: t
  display-line-numbers-mode: t
  ligature-mode: t
  rainbow-delimiters-mode: t
  format-all-mode: t
  global-auto-revert-mode: t
  repeat-mode: t
  ws-butler-global-mode: t
  ws-butler-mode: t
  global-treesit-auto-mode: t
  corfu-popupinfo-mode: t
  global-corfu-mode: t
  corfu-mode: t
  marginalia-mode: t
  savehist-mode: t
  vertico-mode: t
  auto-insert-mode: t
  undo-fu-session-global-mode: t
  undo-fu-session-mode: t
  which-key-mode: t
  electric-pair-mode: t
  desktop-save-mode: t
  recentf-mode: t
  save-place-mode: t
  override-global-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  window-divider-mode: t
  minibuffer-regexp-mode: t
  column-number-mode: t
  line-number-mode: t
  auto-fill-function: do-auto-fill
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t

Load-path shadows:
~/.emacs.d//lisp/aoc hides /home/trev/.emacs.d/elpa/aoc-1.0.0/aoc
~/.emacs.d//lisp/launch-program hides /home/trev/.emacs.d/elpa/launch-program-1.0.0/launch-program
~/.emacs.d//lisp/my-secrets hides /home/trev/.emacs.d/elpa/my-secrets-1.0.0/my-secrets

Features:
(shadow sort mail-extr emacsbug pulse bug-reference eglot
external-completion jsonrpc flymake ert pcase c++-ts-mode c-ts-mode
c-ts-common xref project cc-mode cc-fonts cc-guess cc-menus cc-cmds
cc-styles cc-align cc-engine comp comp-cstr warnings thingatpt helpful
cc-langs cc-vars cc-defs trace cl-print edebug debug backtrace info-look
find-func f help-fns radix-tree elisp-refs s comp-run comp-common novice
misearch multi-isearch mule-util orderless cape-char cape network-stream
nsm erc-track erc-spelling flyspell ispell erc-ring erc-nicks
erc-netsplit erc-menu erc-match erc-list erc-goodies erc-imenu imenu
erc-pcomplete pcomplete erc-button erc-fill erc-stamp erc-join
my-secrets cus-start epa-file erc format-spec erc-backend erc-networks
erc-common erc-compat erc-loaddefs diff-hl-flydiff diff diff-hl log-view
log-edit message sendmail yank-media puny dired dired-loaddefs rfc822
mml mml-sec epa derived epg rfc6068 epg-config mm-decode mm-bodies
mm-encode mail-parse rfc2231 rfc2047 rfc2045 ietf-drums mailabbrev
gmm-utils mailheader add-log pcvs-util vc-dir ewoc vc vc-git diff-mode
track-changes files-x vc-dispatcher jka-compr paredit
display-line-numbers rx ligature rainbow-delimiters format-all
language-id inheritenv autorevert filenotify repeat init gnus nnheader
gnus-util time-date mail-utils range mm-util mail-prsvr cus-edit pp
ws-butler treesit-auto treesit corfu-popupinfo corfu marginalia savehist
vertico compat autoinsert grep compile text-property-search comint
ansi-osc ansi-color ring cus-load undo-fu-session which-key diminish
finder-inf edmacro kmacro elec-pair desktop frameset recentf tree-widget
wid-edit saveplace nord-theme autothemer color lisp-mnt dash use-package
use-package-ensure use-package-delight use-package-diminish
use-package-bind-key bind-key easy-mmode package browse-url xdg url
url-proxy url-privacy url-expand url-methods url-history url-cookie
generate-lisp-file url-domsuf url-util mailcap url-handlers url-parse
auth-source eieio eieio-core icons password-cache json subr-x map
byte-opt url-vars cl-macs gv cl-extra help-mode cl-seq use-package-core
cl-loaddefs cl-lib bytecomp byte-compile info 2048-game-autoloads
ace-window-autoloads aio-autoloads aoc-autoloads autothemer-autoloads
avy-autoloads benchmark-init-autoloads cape-autoloads corfu-autoloads
debbugs-autoloads diff-hl-autoloads diminish-autoloads elfeed-autoloads
emacsql-autoloads envrc-autoloads format-all-autoloads
geiser-guile-autoloads geiser-autoloads git-modes-autoloads
heap-autoloads helpful-autoloads elisp-refs-autoloads f-autoloads
ht-autoloads inheritenv-autoloads language-id-autoloads
launch-program-autoloads ligature-autoloads log4e-autoloads
magit-autoloads magit-section-autoloads dash-autoloads
marginalia-autoloads markdown-mode-autoloads my-secrets-autoloads
orderless-autoloads paredit-autoloads rainbow-delimiters-autoloads
rainbow-mode-autoloads request-autoloads rust-mode-autoloads s-autoloads
sly-autoloads treesit-auto-autoloads undo-fu-autoloads
undo-fu-session-autoloads vertico-autoloads vterm-autoloads
with-editor-autoloads ws-butler-autoloads early-init rmc iso-transl
tooltip cconv eldoc paren electric uniquify ediff-hook vc-hooks
lisp-float-type elisp-mode mwheel term/pgtk-win pgtk-win term/common-win
touch-screen pgtk-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode lisp-mode prog-mode register
page tab-bar menu-bar rfn-eshadow isearch easymenu timer select
scroll-bar mouse jit-lock font-lock syntax font-core term/tty-colors
frame minibuffer nadvice seq simple cl-generic indonesian philippine
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 emoji-zwj charscript
charprop case-table epa-hook jka-cmpr-hook help abbrev obarray oclosure
cl-preloaded button loaddefs theme-loaddefs faces cus-face macroexp
files window text-properties overlay sha1 md5 base64 format env
code-pages mule custom widget keymap hashtable-print-readable backquote
threads dbusbind inotify dynamic-setting system-font-setting
font-render-setting cairo gtk pgtk lcms2 multi-tty move-toolbar
make-network-process tty-child-frames native-compile emacs)

Memory information:
((conses 16 753787 456549) (symbols 48 29546 38) (strings 32 122308 34583)
 (string-bytes 1 4464676) (vectors 16 60371) (vector-slots 8 1478094 442007)
 (floats 8 389 931) (intervals 56 35024 2770) (buffers 992 38))