bug#60298: 30.0.50; switch-to-buffer-other-window opens new frame when split-window-preferred-function is split-window-vertically

[Jean Louis]

Function `switch-to-buffer-other-window' opens new frame when variable
`split-window-preferred-function' is set to `split-window-vertically':

Here is the recipe:

1. emacs -Q

2. (setq split-window-preferred-function 'split-window-vertically)

3. (switch-to-buffer-other-window (get-buffer-create "My buffer"))

My expectation is not that new frame get created under above conditions,
but that window is split vertically.



In GNU Emacs 30.0.50 (build 1, x86_64-pc-linux-gnu, X toolkit, cairo
 version 1.17.6, Xaw3d scroll bars) of 2022-12-22 built on
 protected.rcdrun.com
Repository revision: e98ab3f458b25812eff1b3a7ce6429caece4c891
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101004
System Description: Parabola GNU/Linux-libre

Configured using:
 'configure --with-x-toolkit=lucid --with-mailutils'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
JSON LCMS2 LIBOTF LIBSYSTEMD LIBXML2 M17N_FLT MODULES NOTIFY INOTIFY
PDUMPER PNG RSVG SECCOMP SOUND SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS
TREE_SITTER WEBP X11 XAW3D XDBE XIM XINPUT2 XPM LUCID ZLIB

Important settings:
  value of $LC_ALL: en_US.UTF-8
  value of $LANG: de_DE.UTF-8
  value of $XMODIFIERS: @im=exwm-xim
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  show-paren-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
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media puny dired
dired-loaddefs rfc822 mml mml-sec password-cache epa derived epg rfc6068
epg-config gnus-util 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 subr-x shortdoc
text-property-search help-fns radix-tree cl-extra help-mode cl-loaddefs
cl-lib novice rmc iso-transl tooltip cconv eldoc paren electric uniquify
ediff-hook vc-hooks lisp-float-type elisp-mode 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 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 lcms2 dynamic-setting system-font-setting
font-render-setting cairo x-toolkit xinput2 x multi-tty
make-network-process emacs)

Memory information:
((conses 16 48670 9765)
 (symbols 48 5506 0)
 (strings 32 16234 2490)
 (string-bytes 1 452817)
 (vectors 16 11161)
 (vector-slots 8 167251 13305)
 (floats 8 99 31)
 (intervals 56 490 2)
 (buffers 984 16))

-- 
Jean

Take action in Free Software Foundation campaigns:
https://www.fsf.org/campaigns

In support of Richard M. Stallman
https://stallmansupport.org/