bug#4714: 23.1.50; wrong-type-argument stringp nil in gdb

Please write in English if possible, because the Emacs maintainers
usually do not have translators to read other languages for them.

Your bug report will be posted to the [email protected] mailing list.

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

If you download the program
http://clivecooper.co.uk/tutorial/changetime.tar.gz
from
http://clivecooper.co.uk/tutorial/index.html

(this was just used to get a small enough program which replicated the
bug - I'm guessing there may be a issue with qt moc'ed file here)

the tar file includes a compiled version of the program - but you should
probably build it yourself though you'll need a qt dev environment.

Run the program under gdb and when the program window appears interrupt
it in gdb and once interrupted move one level up the call stack.

You then get a wrong-type-argument stringp nil error:

Debugger entered--Lisp error: (wrong-type-argument stringp nil)
  string-match("//+" nil)
  gud-find-file(nil)
  gud-display-line(nil 83)
  gud-display-frame()
  gdb-frame-handler()


If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
If you would like to further debug the crash, please read the file
/home/robert/emacs/etc/DEBUG for instructions.


In GNU Emacs 23.1.50.4 (x86_64-unknown-linux-gnu, GTK+ Version 2.16.1)
 of 2009-10-13 on robert-laptop
Windowing system distributor `The X.Org Foundation', version 11.0.10600000
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_GB.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Emacs-Lisp

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


Recent messages:
This version of GDB doesn't support non-stop mode.  Turning it off.
Command: up 1
error in process filter: gud-find-file: Wrong type argument: stringp, nil
error in process filter: Wrong type argument: stringp, nil
Mark set

Load-path shadows:
None found.

Features:
(shadow mail-extr message ecomplete rfc822 mml mml-sec password-cache
mm-decode mm-bodies mm-encode mailcap mail-parse rfc2231 rfc2047 rfc2045
qp ietf-drums mailabbrev nnheader gnus-util netrc time-date mm-util
mail-prsvr gmm-utils wid-edit mailheader canlock sha1 hex-util hashcash
mail-utils emacsbug sendmail help-mode view debug gdb-mi bindat json gud
easy-mmode comint ring multi-isearch parse-time vc-cvs cc-mode cc-fonts
easymenu cc-menus cc-cmds cc-styles cc-align cc-engine cc-vars cc-defs
dired regexp-opt tooltip ediff-hook vc-hooks lisp-float-type mwheel
x-win x-dnd tool-bar dnd fontset image fringe lisp-mode register page
menu-bar rfn-eshadow timer select scroll-bar mldrag mouse jit-lock
font-lock syntax facemenu font-core frame cham georgian utf-8-lang
misc-lang vietnamese tibetan thai tai-viet lao korean japanese hebrew
greek romanian slovak czech european ethiopic indian cyrillic chinese
case-table epa-hook jka-cmpr-hook help simple abbrev loaddefs button
minibuffer faces cus-face text-properties overlay md5 base64 format env
code-pages mule custom widget hashtable-print-readable backquote
make-network-process gtk x-toolkit x multi-tty emacs)

-- 
Robert A J Marshall,  
TNEI Services Ltd, 86-90 London Road, Manchester, M1 2PW 
web: http://IPSA-Power.com