Subject: bug#56237: 29.0.50; delete-forward-char fails to delete character

From: [email-masked]
Date: Sun, 26 Jun 2022 21:37:07 +0530

delete-forward-char fails to delete if the point is between two composed
characters.  To demonstrate,

        1. emacs -Q
        2. Yank "ரு போ" to the *scratch* buffer
        3. Place the cursor on the space character and say <Delete>

Observe how delete-forward-char does nothing.

In GNU Emacs 29.0.50 (build 22, x86_64-pc-linux-gnu, X toolkit, Xaw scroll bars)
 of 2022-06-25 built on astatine
Repository revision: 376ecd5346496a4f11a3bc93814b03d7a884b841
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101003
System Description: Debian GNU/Linux 11 (bullseye)

Configured using:
 'configure --with-modules --with-sound=alsa --with-x-toolkit=lucid
 --with-json --without-xaw3d --without-gconf --without-libsystemd
 --with-x --without-cairo'

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

Important settings:
  value of $LC_MONETARY: ta_IN.UTF-8
  value of $LC_NUMERIC: ta_IN.UTF-8
  value of $LANG: en_GB.UTF-8
  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 text-property-search time-date subr-x mm-decode
mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader
sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils
cus-start cus-load ind-util quail help-mode cl-loaddefs cl-lib rmc
iso-transl tooltip 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 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 x-toolkit
xinput2 x multi-tty make-network-process emacs)

Memory information:
((conses 16 110282 8844)
 (symbols 48 6549 0)
 (strings 32 40942 1993)
 (string-bytes 1 619696)
 (vectors 16 23168)
 (vector-slots 8 327896 13098)
 (floats 8 24 24)
 (intervals 56 2398 6)
 (buffers 992 11))