Subject: 26.3; Strange bidi behavior
From: [email-masked] (Niels Möller)
To: [email-masked]
Date: Fri, 04 Sep 2020 21:36:41 +0200
List-Id: <debbugs-submit.debbugs.gnu.org>

I get a pretty confusing behavior when I load the file at

  https://www.lysator.liu.se/~nisse/misc/emacs-bidi-bug-2.txt

This is what it looks like

  https://www.lysator.liu.se/~nisse/misc/emacs-bidi-bug-2.png

I'll try to describe the behavior I get when loading the file with

  emacs -Q emacs-bidi-bug-2.txt

(I'm not sure exactly what intended behavior is, but what I see is quite
confusing). The file contains some arabic characters (originating in a
discussion of the vatican reportedly registering an arabic domain name
meaning "katholic"), followed by some Swedish text.

The Swedish text is displayed mostly in left-to-right order (except for
punctuation characters), but right-justified in the buffer, and to me it
seems like some parts of emacs thinks the text is rendered
right-to-left.

More specifically, C-f moves point in the expected "logical order" of
the text, which is mostly to the right on the screen. However pressing
the right-arrow key (bound to right-char) moves cursor to the left on
most parts of this text (the opposite direction of C-f (forward-char)),
despite the text being rendered in left-to-right order.

I would have expected the later part of the file to be displayed
left-justified in left-to-right order, with the exception of the single
word "كاثولي" rendered right-to-left.

Regards,
/Niels

In GNU Emacs 26.3 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3.24.20)
 of 2020-05-17, modified by Debian built on x86-csail-01
Windowing system distributor 'The X.Org Foundation', version
 11.0.12004000

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/26.3/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/26.3/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/26.3/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/26.3/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --without-gconf --with-mailutils --with-x=yes
 --with-x-toolkit=gtk3 --with-toolkit-scroll-bars 'CFLAGS=-g -O2
 -fdebug-prefix-map=/build/emacs-mHAik2/emacs-26.3+1=.
 -fstack-protector-strong
 -Wformat -Werror=format-security -Wall' 'CPPFLAGS=-Wdate-time
 -D_FORTIFY_SOURCE=2' LDFLAGS=-Wl,-z,relro'

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GSETTINGS GLIB
NOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM THREADS LIBSYSTEMD LCMS2

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

Major mode: Text

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-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
  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/lyskom-elisp-client hides
/usr/share/emacs/site-lisp/lyskom-elisp-client/lyskom-elisp-client

Features:
(pp shadow sort mail-extr emacsbug message dired dired-loaddefs
format-spec rfc822 mml mml-sec epa derived epg epg-config gnus-util
rmail rmail-loaddefs mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils parse-time browse-url wid-edit
network-stream puny nsm rmc seq auth-source cl-seq eieio eieio-core
cl-macs eieio-loaddefs password-cache starttls tls gnutls lyskom-rest
string lyskom-menus lyskom-ansaphone lyskom-messages mship-edit
lyskom-cache lyskom-services lyskom-mime lyskom-aux-items lyskom-command
advice lyskom-clienttypes lyskom-types lyskom-language-sv lyskom-strings
lyskom-language lyskom-macros lyskom-vars lyskom-feature lyskom-defvar
lyskom edmacro kmacro cl-print byte-opt gv bytecomp byte-compile cconv
thingatpt cl-extra help-fns radix-tree help-mode easymenu cl-loaddefs
cl-lib elec-pair time-date mule-util 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 menu-bar rfn-eshadow isearch timer select
scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame 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 minibuffer 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 move-toolbar gtk x-toolkit x
multi-tty make-network-process emacs)

Memory information:
((conses 16 264803 23621)
 (symbols 48 30298 0)
 (miscs 40 845 608)
 (strings 32 61450 3495)
 (string-bytes 1 1701594)
 (vectors 16 37130)
 (vector-slots 8 1636019 140596)
 (floats 8 99 394)
 (intervals 56 3949 356)
 (buffers 992 21))

-- 
Niels Möller. PGP-encrypted email is preferred. Keyid 368C6677.
Internet email is subject to wholesale government surveillance.