bug#21730: 25.0.50; Random errors in redisplay--pre-redisplay-functions

[Michael Welsh Duggan]

I don't have a recipe for this.  Every now again I get the following in
my *Messages* buffer:

  redisplay--pre-redisplay-functions: (args-out-of-range 0)

I turned on debug-on-error, and got the following backtrace:

  Debugger entered--Lisp error: (args-out-of-range 0)
    get-char-property(0 cursor-sensor-functions)
    cursor-sensor--detect(#<window 224 on *Group*>)
    run-hook-with-args(cursor-sensor--detect #<window 224 on *Group*>)
    redisplay--pre-redisplay-functions(t)
    apply(redisplay--pre-redisplay-functions t)
    #[128 "\300\301\"\210\300\302\"\207" [apply 
redisplay--pre-redisplay-functions ignore nil] 4 nil nil](t)
    redisplay_internal\ \(C\ function\)()

This happens infrequently, about a couple of times a day.  I cannot make
this happen on demand, but I can add debugging code if led in the
correct direction.
  

In GNU Emacs 25.0.50.1 (x86_64-pc-linux-gnu, X toolkit)
 of 2015-10-09
Repository revision: f7acc9ce65bc6c1080aa6c85618cf854ed0047ee
Windowing system distributor 'The X.Org Foundation', version 11.0.11702000
System Description:     Debian GNU/Linux unstable (sid)

Configured using:
 'configure --without-toolkit-scroll-bars --with-x-toolkit=lucid
 'CFLAGS=-Og -ggdb3' --with-wide-int --with-gameuser=:staff'

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND GPM DBUS GCONF GSETTINGS NOTIFY ACL
GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB LUCID X11

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

Major mode: Dired by date

Minor modes in effect:
  display-time-mode: t
  magit-auto-revert-mode: t
  shell-dirtrack-mode: t
  diff-auto-refine-mode: t
  tooltip-mode: t
  global-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
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  line-number-mode: t

Recent messages:
Saving /home/md5i/.newsrc.eld...
Saving file /home/md5i/.newsrc.eld...
Wrote /home/md5i/.newsrc.eld
Saving /home/md5i/.newsrc.eld...done
Checking new news...
Reading active file from ~/Mail via nnml...done
nnimap read 0k from localhost
Reading active file via nndraft...done
Checking new news...done
Scanning for dabbrevs...done

Load-path shadows:
/usr/share/emacs/site-lisp/rst hides 
/usr/local/share/emacs/25.0.50/lisp/textmodes/rst

Features:
(shadow emacsbug gnus-fun calc-alg calc-ext calc-menu calc calc-loaddefs
calc-macs doc-view css-mode smie image-mode pcmpl-unix debug js
nxml-uchnm rng-xsd xsd-regexp rng-cmpct rng-nxml rng-valid nxml-mode
nxml-outln nxml-rap nxml-glyph conf-mode cus-edit cus-start cus-load
tramp-cache rect python tramp-sh json dabbrev gud imenu man time-stamp
whitespace tabify two-column iso-transl make-mode dired-aux
vc-dispatcher vc-hg cc-mode cc-fonts cc-guess cc-menus cc-cmds misearch
multi-isearch gnus-dup shr-color color url-util url-parse url-vars shr
dom subr-x browse-url flow-fill jka-compr mm-archive qp sort gnus-cite
mail-extr gnus-async gnus-bcklg gnus-ml disp-table gnus-topic
cursor-sensor utf-7 nndraft nnmh epa-file network-stream nsm starttls
nnml gnus-agent gnus-srvr gnus-score score-mode nnvirtual gnus-msg
gnus-art mm-uu mml2015 mm-view mml-smime smime dig gnus-cache gnus-demon
nntp gnutls nnir gnus-sum gnus-group gnus-undo gnus-start gnus-cloud
nnimap nnmail mail-source tls utf7 netrc nnoo parse-time gnus-spec
gnus-int gnus-range gnus-win gnus gnus-ems nnheader flyspell ispell
yaml-mode uptimes pp descr-text time sieve-manage rng-loc rng-uri
rng-parse rng-match rng-dt rng-util rng-pttrn nxml-parse nxml-ns
nxml-enc xmltok nxml-util sgml-mode psvn wid-edit cl magit-key-mode
magit view tramp tramp-compat auth-source eieio byte-opt bytecomp
byte-compile cl-extra cconv eieio-core cl-macs gv gnus-util time-date
password-cache tramp-loaddefs trampver shell pcomplete advice grep
compile epa derived epg epg-config diff-mode autorevert filenotify
git-rebase-mode thingatpt git-commit-mode server log-edit easy-mmode
pcvs-util add-log mailcap message sendmail format-spec rfc822 mml
mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045
ietf-drums mm-util help-fns help-mode mail-prsvr mailabbrev mail-utils
gmm-utils mailheader lua-mode edmacro rx generated generic-x ediff-merg
ediff-wind ediff-diff ediff-mult ediff-help ediff-init ediff-util ediff
debian-el debian-el-loaddefs dired-x easymenu dired cc-styles cc-align
cc-engine cc-vars cc-defs ange-ftp comint ansi-color ring cl-seq kmacro
cl-loaddefs pcase cl-lib mule-util tooltip eldoc electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel x-win term/common-win x-dnd
tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment
elisp-mode lisp-mode prog-mode register page menu-bar rfn-eshadow timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
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 charscript
case-table epa-hook jka-cmpr-hook help simple abbrev 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
dynamic-setting system-font-setting font-render-setting x-toolkit x
multi-tty make-network-process emacs)

Memory information:
((conses 16 885412 104614)
 (symbols 48 49376 228)
 (miscs 40 1199 2821)
 (strings 32 113818 15421)
 (string-bytes 1 3593164)
 (vectors 16 52064)
 (vector-slots 8 1440209 35827)
 (floats 8 761 638)
 (intervals 56 24560 199)
 (buffers 976 98)
 (heap 1024 103928 10949))

-- 
Michael Welsh Duggan
(md5i@md5i.com)