bug#1521: 23.0.60; Emacs losing values of variables

[Ashish Shukla आशीष =?UTF-8?Q?=E0=A4=B6=E0=A5=81=E0=A4=95=E0=A5=8D=E0=A4=B2]

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 emacs-pretest-bug@gnu.org mailing list.

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:
 
I've noticed that Emacs is losing values of the variables after sometime
due to this I'm not able to use semantic and erc properly. Most of the
times, I've experienced this with ERC and I experienced it only in Emacs
CVS not in 22.x. When I tried to expand a nick in ERC which is currently
showing #mysql channel, I got following error (bytecode string is
replaced with ...):

,----
| Debugger entered--Lisp error: (wrong-type-argument arrayp nil)
|   pcomplete-erc-nicks(": " t)
|   (append (pcomplete-erc-commands) (pcomplete-erc-nicks 
erc-pcomplete-nick-postfix t))
|   eval((append (pcomplete-erc-commands) (pcomplete-erc-nicks 
erc-pcomplete-nick-postfix t)))
|   pcomplete--here((append (pcomplete-erc-commands) (pcomplete-erc-nicks 
erc-pcomplete-nick-postfix t)) nil nil nil)
|   pcomplete/erc-mode/complete-command()
|   byte-code("...")
|   pcomplete-completions()
|   byte-code("...")
|   pcomplete(1)
|   call-interactively(pcomplete)
|   erc-pcomplete()
|   run-hook-with-args-until-success(erc-pcomplete)
|   erc-complete-word()
|   call-interactively(erc-complete-word nil nil)
`----

But if I do '/names' and then try to complete nick names in ERC, it
completes as expected. So I think this is the problem with Emacs losing
values of variables. This is not always reproducible.

Following is the output of "(message "%s" (buffer-local-variables))"
form executed in #mysql buffer.

"((buffer-display-time 18750 45133 502023) (buffer-display-count . 3) 
(buffer-invisibility-spec t) (buffer-file-truename) (point-before-scroll) 
(buffer-auto-save-file-format . t) (buffer-file-format) 
(enable-multibyte-characters . t) (mark-active) (local-abbrev-table . [ 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 0 0 0 0]) (header-line-format . abbe on #mysql (+tnc,lag:0) 
5.1 GA its out! | Guidelines: http://hashmysql.org/ | sense of humor mandatory 
| MMPRPG | We don't support phpMyAdmin | MySQL GUI TOOLS SUCK! Use at own risk 
| We do not give answers, we help you find solutions ([raymond], 23:46:20 
2008/12/08)) (mode-name . ERC) (major-mode . erc-mode) (buffer-read-only) 
(buffer-auto-save-file-name) (buffer-saved-size . 0) (buffer-backed-up) 
(default-directory . ~/) (buffer-file-name) (buffer-undo-list nil (84143 . 
84144) nil (84116 . 84119) nil (m . -84116) nil (y . -84117) nil (- . -84118) 
nil (84114 . 84119) nil (  . -84114) nil (84110 . 84115) nil (84132 . 84134) 
nil (84112 . 84132) nil (f . -84112) nil (84110 . 84113) nil (( . -84110) nil 
(i . -84111) nil (n . -84112) nil (84110 . 84113) nil (j . -84110) (#<marker at 
84144 in #mysql> . -1) nil (a . -84111) (#<marker at 84144 in #mysql> . -1) nil 
(s . -84112) (#<marker at 84144 in #mysql> . -1) nil (84110 . 84113) nil (j . 
-84110) (#<marker at 84144 in #mysql> . -1) nil (a . -84111) (#<marker at 84144 
in #mysql> . -1) nil (84110 . 84112)) (next-line-add-newlines) 
(paragraph-separate . \\|\\(^ERC> \\)) (paragraph-start . \\(ERC> \\)) 
(pcomplete-ignore-case . t) (pcomplete-use-paring) (pcomplete-suffix-list 32 
58) (pcomplete-parse-arguments-function . pcomplete-parse-erc-arguments) 
(pcomplete-command-completion-function . pcomplete/erc-mode/complete-command) 
(pcomplete-command-name-function . pcomplete-erc-command-name) 
(pcomplete-default-completion-function . #[nil \\300\\301\\302\\211\\211$\\207 
[pcomplete--here (pcomplete-erc-nicks) nil] 5]) (imenu-create-index-function . 
erc-create-imenu-index) (erc-server-announced-name . freenode) 
(erc-server-connected . t) (erc-server-process . socks<1>) (erc-insert-marker . 
#<marker at 84105 in #mysql>) (erc-input-marker . #<marker at 84110 in #mysql>) 
(erc-default-recipients #mysql) (erc-server-current-nick) (erc-server-users) 
(erc-channel-users . #<hash-table 'equal nil 543/730 0x938b690>) 
(erc-server-filter-data) (erc-channel-topic . 5.1 GA its out! | Guidelines: 
http://hashmysql.org/ | sense of humor mandatory | MMPRPG | We don't support 
phpMyAdmin | MySQL GUI TOOLS SUCK! Use at own risk | We do not give answers, we 
help you find solutions^O ([raymond], 23:46:20 2008/12/08)) 
(erc-channel-user-limit) (erc-channel-key) (erc-invitation) (erc-channel-list) 
(erc-bad-nick) (erc-logged-in) (erc-default-nicks abbe) (erc-session-password) 
(erc-dbuf) (erc-session-server . freenode) (erc-session-port . 6667) 
(erc-session-user-full-name . Ashish Shukla) (erc-last-saved-position . 
#<marker at 84104 in #mysql>) (mode-line-buffer-identification #mysql@freenode 
) (mode-line-process ) (erc-server-last-sent-time . 1228831904.0) 
(erc-channel-new-member-names) (erc-timestamp-last-inserted-left . 
[Tue Dec  9 2008]
) (erc-timestamp-last-inserted-right .  [23:24]) (font-lock-mode . t) 
(char-property-alias-alist (face font-lock-face)) (change-major-mode-hook 
font-lock-change-mode t) (font-lock-mode-major-mode . erc-mode) 
(auto-composition-mode . t) (after-change-functions 
auto-composition-after-change t) (auto-composition-function . 
auto-compose-chars) (auto-composition-mode-major-mode . erc-mode) 
(erc-channel-modes t n c) (pcomplete-current-completions) 
(pcomplete-last-completion-raw))"

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


In GNU Emacs 23.0.60.1 (x86_64-pc-linux-gnu, GTK+ Version 2.12.11)
 of 2008-12-06 on chateau
Windowing system distributor `The X.Org Foundation', version 11.0.10502000
configured using `configure  '--prefix=/usr' '--host=x86_64-pc-linux-gnu' 
'--mandir=/usr/share/man' '--infodir=/usr/share/info' '--datadir=/usr/share' 
'--sysconfdir=/etc' '--localstatedir=/var/lib' '--program-suffix=-emacs-23' 
'--infodir=/usr/share/info/emacs-23' '--with-sound' '--with-x' 
'--with-toolkit-scroll-bars' '--with-gif' '--with-jpeg' '--with-png' 
'--with-rsvg' '--with-tiff' '--with-xpm' '--with-freetype' '--with-xft' 
'--with-libotf' '--with-m17n-flt' '--with-x-toolkit=gtk' '--without-hesiod' 
'--without-kerberos' '--without-kerberos5' '--with-gpm' '--with-dbus' 
'--libdir=/usr/lib64' '--build=x86_64-pc-linux-gnu' 
'build_alias=x86_64-pc-linux-gnu' 'host_alias=x86_64-pc-linux-gnu' 'CFLAGS=-O2 
-pipe -mtune=nocona -march=nocona -ggdb' 'LDFLAGS=-Wl,--hash-style,both''

Important settings:
  value of $LC_ALL: en_US.UTF-8
  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_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:
  diff-auto-refine-mode: t
  erc-ring-mode: t
  erc-track-mode: t
  erc-track-minor-mode: t
  erc-services-mode: t
  erc-notify-mode: t
  erc-networks-mode: t
  erc-match-mode: t
  erc-netsplit-mode: t
  erc-pcomplete-mode: t
  erc-button-mode: t
  erc-stamp-mode: t
  erc-smiley-mode: t
  display-time-mode: t
  show-paren-mode: t
  tooltip-mode: t
  tool-bar-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-encryption-mode: t
  auto-compression-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
SPC r e p o r t - e m a c s - b u g ) SPC <end> <C-left> 
<C-left> <C-left> <C-left> <C-left> <C-left> o r SPC 
s o m e SPC p r o b l e m SPC w i t h SPC m y SPC c 
o n f i g u r a t i o n . <backspace> , SPC p a s t 
e d SPC a t SPC <C-left> <C-left> e r r o r SPC i s 
SPC <return> <down-mouse-1> <mouse-1> q <down-mouse-1> 
<mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> 
M-x <up> <return> <up> <return> <help-echo> <down-mouse-1> 
<mouse-2> <down-mouse-5> <mouse-5> <double-down-mouse-5> 
<double-mouse-5> <triple-down-mouse-5> <triple-mouse-5> 
<down-mouse-4> <mouse-4> <double-down-mouse-4> <double-mouse-4> 
<down-mouse-5> <mouse-5> <double-down-mouse-5> <double-mouse-5> 
<down-mouse-4> <mouse-4> <down-mouse-4> <mouse-4> <down-mouse-4> 
<mouse-4> <down-mouse-4> <mouse-4> <down-mouse-4> <mouse-4> 
<down-mouse-5> <mouse-5> <double-down-mouse-5> <double-mouse-5> 
<down-mouse-5> <mouse-5> <down-mouse-1> <mouse-1> <escape> 
: m a i l - u s e r - a g e n t <return> <down-mouse-1> 
<mouse-1> C-x C-e <down-mouse-1> <mouse-1> q <down-mouse-5> 
<mouse-5> <down-mouse-1> <mouse-1> <help-echo> <help-echo> 
<help-echo> <down-mouse-1> <mouse-1> ( s e t q SPC 
m a i l - u s e r - a g e n t SPC ' g n u <backspace> 
<backspace> <backspace> <backspace> <backspace> <C-left> 
C-h f C-g C-h v <return> <down-mouse-1> <mouse-1> SPC 
' g n u s - u s e r - a g e n t ) C-x C-e C-SPC <home> 
C-w <down-mouse-1> <mouse-1> q <help-echo> <help-echo> 
<help-echo> <down-mouse-1> <mouse-1> o o p s M-x <up> 
<return> <up> C-g <backspace> <backspace> <backspace> 
<backspace> c o n s o <tab> M-x <up> <return> <help-echo> 
<down-mouse-1> <mouse-movement> <mouse-movement> <drag-mouse-1> 
<help-echo> <down-mouse-1> <mouse-1> <down-mouse-1> 
<mouse-movement> <mouse-movement> <drag-mouse-1> <help-echo> 
<down-mouse-1> <mouse-movement> <mouse-movement> <drag-mouse-1> 
<down-mouse-1> <mouse-movement> <mouse-movement> <drag-mouse-1> 
<up> <down-mouse-1> <mouse-1> q <help-echo> <down-mouse-1> 
<mouse-1> <help-echo> <help-echo> <down-mouse-1> <mouse-1> 
M-x <up> <return>

Recent messages:
my-gnus-user-agent
nil
Back to top level.
Quit
Type "q" to restore this window.
gnus-user-agent
Mark set
Quit
Entering debugger...
Back to top level.

Hope this helps.

TiA
-- 
Ashish Shukla