bug#29506: find-composition segfaults

[Edgard Bikelis]

Hi!

I was testing decomposing some characters in malayalam, and by evaluating this:

(find-composition 0 1 "ദേ")

emacs segfaults when it’s in gui mode, but not when it’s on the
console, with the -nw option. I have asked on #emacs on freenode, and
other people had the same effect on version 25.2 and 26. It seems to
happen with unicode past some high number, it doesn’t happen with "á"
for instance, with a+ combining acute above, but it does happen in
Arabic also, like with "ڜ".

Thanks,

Edgard

In GNU Emacs 27.0.50 (build 2, x86_64-pc-linux-gnu, GNU/LessTif
Version 2.1 Release 0.95.2)
 of 2017-11-28 built on svar
Repository revision: c816e647ebf128eccc9df6ce3d64ebc5a5554aec
Windowing system distributor 'The X.Org Foundation', version 11.0.11704000
Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Configured using:
 'configure --with-x-toolkit=motif'

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GSETTINGS NOTIFY
ACL GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB TOOLKIT_SCROLL_BARS
MOTIF X11 LIBSYSTEMD LCMS2

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

Major mode: Lisp Interaction

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

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny seq byte-opt gv
bytecomp byte-compile cconv cl-loaddefs cl-lib dired dired-loaddefs
format-spec rfc822 mml easymenu mml-sec password-cache 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 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 dbusbind inotify lcms2
dynamic-setting system-font-setting font-render-setting motif x-toolkit
x multi-tty make-network-process emacs)

Memory information:
((conses 16 94775 7532)
 (symbols 48 20346 1)
 (miscs 40 47 118)
 (strings 32 29096 1253)
 (string-bytes 1 753509)
 (vectors 16 13955)
 (vector-slots 8 491574 10496)
 (floats 8 51 66)
 (intervals 56 227 0)
 (buffers 992 11))