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

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/

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

[Eli Zaretskii]

tags 60298 notabug
thanks

> From: Jean Louis <bugs@gnu.support>
> Date: Sat, 24 Dec 2022 15:49:37 +0300
> 
> 
> 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)

You cannot use split-window-vertically as the value of
split-window-preferred-function.  The doc string of
split-window-preferred-function says:

  This function is called with a window as single argument and is
  supposed to split that window and return the new window.

Whereas the signature of split-window-vertically is:

  (split-window-vertically &optional SIZE WINDOW-TO-SPLIT)

So it accepts zero to 2 arguments, but if called with one argument, it
interprets the argument as the size:

  If optional argument SIZE is omitted or nil, both windows get the
  same height, or close to it.  If SIZE is positive, the upper
  (selected) window gets SIZE lines.  If SIZE is negative, the
  lower (new) window gets -SIZE lines.

I see no bug here, just a cockpit error.

If you want to prefer vertical splitting, you should do this with
other variables, as the doc string of split-window-preferred-function
says:

  The default is to call the function ‘split-window-sensibly’ which
  tries to split the window in a way which seems most suitable.
  You can customize the options ‘split-height-threshold’ and/or
  ‘split-width-threshold’ in order to have ‘split-window-sensibly’
  prefer either vertical or horizontal splitting.

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

[Stefan Kangas]

Eli Zaretskii <eliz@gnu.org> writes:

> tags 60298 notabug
> thanks
[...]
>
> I see no bug here, just a cockpit error.

I'm therefore closing this bug report.