23.0.60; Error on zero length completion

[David Hansen]

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 address@hidden mailing list.

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

Hello,

to reproduce:

emacs -Q M-x <TAB>

Fix attached.

2008-04-26  David Hansen  <address@hidden>
        * minibuffer.el (completion-emacs22-try-completion): Check for zero
        length completion.

*** minibuffer.el.~1.27.~       2008-04-24 13:38:54.000000000 +0200
--- minibuffer.el       2008-04-26 01:34:55.000000000 +0200
***************
*** 1002,1008 ****
        ;; Merge a trailing / in completion with a / after point.
        ;; We used to only do it for word completion, but it seems to make
        ;; sense for all completions.
!       (if (and (eq ?/ (aref completion (1- (length completion))))
                 (not (zerop (length suffix)))
                 (eq ?/ (aref suffix 0)))
            ;; This leaves point before the / .
--- 1002,1009 ----
        ;; Merge a trailing / in completion with a / after point.
        ;; We used to only do it for word completion, but it seems to make
        ;; sense for all completions.
!       (if (and (< 0 (length completion))
!              (eq ?/ (aref completion (1- (length completion))))
                 (not (zerop (length suffix)))
                 (eq ?/ (aref suffix 0)))
            ;; This leaves point before the / .

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/dhansen/share/emacs/23.0.60/etc/DEBUG for instructions.


In GNU Emacs 23.0.60.2 (i686-pc-linux-gnu, GTK+ Version 2.12.9)
 of 2008-04-24 on robotron
Windowing system distributor `The X.Org Foundation', version 11.0.10400090
configured using `configure  '--prefix=/home/dhansen' '--disable-sound' 
'--disable-pop' '--without-gpm' '--without-toolkit-scroll-bars' 
'--disable-font-backend' '--with-x-toolkit=gtk''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: en_US.UTF-8
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t

Major mode: ERC

Minor modes in effect:
  erc-list-mode: t
  erc-menu-mode: t
  erc-ring-mode: t
  erc-pcomplete-mode: t
  erc-netsplit-mode: t
  erc-spelling-mode: t
  erc-truncate-mode: t
  erc-smiley-mode: t
  erc-irccontrols-mode: t
  erc-noncommands-mode: t
  erc-move-to-prompt-mode: t
  erc-readonly-mode: t
  erc-scrolltobottom-mode: t
  erc-services-mode: t
  erc-networks-mode: t
  erc-autojoin-mode: t
  erc-track-mode: t
  erc-track-minor-mode: t
  erc-match-mode: t
  erc-button-mode: t
  erc-fill-mode: t
  erc-stamp-mode: t
  shell-dirtrack-mode: t
  flyspell-mode: t
  global-visible-mark-mode: t
  visible-mark-mode: t
  which-function-mode: t
  show-paren-mode: t
  iswitchb-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-compression-mode: t
  line-number-mode: t
  abbrev-mode: 1

Recent input:
M-> c v s SPC C-a C-k s h e l l <return> C-x o C-x 
b s t u g C-g C-x b s t u f f C-g C-x C-f s t u g g 
<backspace> <backspace> f f / s t u g <backspace> f 
f . o r <tab> <return> C-n C-n C-n C-n C-n C-n C-n 
<tab> <tab> C-n C-n C-n C-SPC M-} M-w C-x o C-y <return> 
C-x o C-x o d <backspace> c d SPC ~ / s r <tab> w m 
<tab> <backspace> <backspace> e m <tab> a <tab> <return> 
C-y <return> C-x o C-x b e m a <return> ( s y t e m 
C-a C-k C-h v s y s <tab> h o <tab> <M-backspace> <tab> 
n a <tab> <return> s <backspace> s u <backspace> y 
s t e m - n a m e <return> C-x o C-x b s h e <return> 
M-> n i c e SPC - 1 9 SPC m a k e <return> c d SPC 
l i s <tab> <return> m a k SPC e <backspace> <backspace> 
e SPC r e c o m p i l e SPC E M A C S = . . / s r c 
/ e m a c s <return> c d SPC . . / <return> m a k e 
<return> M-v M-v M-v M-> C-x b e s h <return> M-v M-v 
M-v M-> C-x b s h e <return> c d SPC <backspace> <backspace> 
<backspace> c d SPC s r <tab> <return> . / e m a <tab> 
c <tab> s <tab> <return> M-p SPC - ! <backspace> Q 
<return> C-x o C-x 1 M-x r e p o <tab> r <tab> e m 
<tab> b u <tab> g <backspace> <return>

Recent messages:
Type C-x 4 C-o RET to restore the other window.
Mark set
Partially completed
~/src/emacs/lisp 
~/src/emacs 
Mark set [2 times]
Completed
~/src/emacs/src 
History item: 1
Making completion list...