bug#12102: 24.1.50; Strange interaction between completion and savehist

[Reuben Thomas]

Here's a short file:

(custom-set-variables
 '(savehist-mode t nil (savehist))
 '(tab-always-indent (quote complete)))
;; "info"

Call it foo.el, and start: emacs -Q -l foo.el foo.el

Then go down to the commented string, put point on the "i" of "info" and
press TAB. The string becomes "iinfo", and, with another TAB,
"idlwave-routine-info".

Without the savehist line in foo.el, the completion works as I'd expect:
it offers a choice of elisp symbols.

Why does configuring savehist-mode change this behavior?


In GNU Emacs 24.1.50.2 (x86_64-unknown-linux-gnu, GTK+ Version 2.24.10)
 of 2012-07-14 on skwd
Bzr revision: 109087 cyd@gnu.org-20120714053223-jxkxt958pqg8tisb
Windowing system distributor `The X.Org Foundation', version 11.0.11103000
Important settings:
  value of $LC_MONETARY: en_GB.UTF-8
  value of $LC_NUMERIC: en_GB.UTF-8
  value of $LC_TIME: en_GB.UTF-8
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Emacs-Lisp

Minor modes in effect:
  TeX-PDF-mode: t
  recentf-mode: t
  show-paren-mode: t
  server-mode: t
  savehist-mode: t
  minibuffer-electric-default-mode: t
  iswitchb-mode: t
  icomplete-mode: t
  global-auto-revert-mode: t
  desktop-save-mode: t
  yas/minor-mode: t
  tooltip-mode: t
  mouse-wheel-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
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
<tab> C-_ C-a C-x 1 C-x C-f ~ / . e n a c s <backspace> 
<backspace> <backspace> <backspace> <backspace> <backspace> 
<backspace> <backspace> <M-backspace> <M-backspace> 
<M-backspace> <M-backspace> <M-backspace> . e m c a 
s C-g M-SPC C-_ M-x c u s t o m i z e - v a r a i b 
l e <backspace> <backspace> <backspace> <backspace> 
<backspace> a i b l e <backspace> <backspace> <backspace> 
<backspace> <backspace> i a b l e <return> t a b - 
a l w a <tab> <return> <help-echo> <help-echo> <down-mouse-1> 
<help-echo> <down-mouse-1> <help-echo> q <right> <right> 
<right> <right> <right> <right> <right> <right> <right> 
<right> <right> <right> <right> <right> <right> <right> 
<right> <right> <right> <right> <right> <right> <right> 
<right> <right> <right> <right> <right> <right> <right> 
<right> <right> <right> <right> <right> <right> <right> 
<right> <right> <right> <left> <left> <right> <tab> 
<tab> <tab> <tab> <down> <down> <down> M-x r e p o 
r t - b e m <backspace> <backspace> <backspace> e m 
<tab> <return>

Recent messages:
Setting up indent for shell type sh
setting up indent stuff
Indentation variables are now local.
Indentation setup for shell type sh
Setting up indent for shell type sh
setting up indent stuff
Indentation variables are now local.
Indentation setup for shell type sh
Loading info...done
Lazy desktop load complete

Load-path shadows:
/home/rrt/.emacs.d/elpa/dictionary-1.8.7/dictionary-init hides 
/usr/local/share/emacs/24.1.50/site-lisp/dictionary-el/dictionary-init
/home/rrt/.emacs.d/elpa/dictionary-1.8.7/dictionary hides 
/usr/local/share/emacs/24.1.50/site-lisp/dictionary-el/dictionary
/home/rrt/.emacs.d/elpa/dictionary-1.8.7/link hides 
/usr/local/share/emacs/24.1.50/site-lisp/dictionary-el/link
/home/rrt/.emacs.d/elpa/dictionary-1.8.7/connection hides 
/usr/local/share/emacs/24.1.50/site-lisp/dictionary-el/connection
/home/rrt/local/share/emacs/site-lisp/dict hides 
/usr/local/share/emacs/24.1.50/site-lisp/emacs-goodies-el/dict
/usr/local/share/emacs/24.1.50/site-lisp/auctex/tex-style hides 
/usr/share/emacs/site-lisp/auctex/tex-style
/usr/local/share/emacs/24.1.50/site-lisp/auctex/tex-mik hides 
/usr/share/emacs/site-lisp/auctex/tex-mik
/usr/local/share/emacs/24.1.50/site-lisp/auctex/multi-prompt hides 
/usr/share/emacs/site-lisp/auctex/multi-prompt
/usr/local/share/emacs/24.1.50/site-lisp/auctex/tex-jp hides 
/usr/share/emacs/site-lisp/auctex/tex-jp
/usr/local/share/emacs/24.1.50/site-lisp/auctex/tex-info hides 
/usr/share/emacs/site-lisp/auctex/tex-info
/usr/local/share/emacs/24.1.50/site-lisp/auctex/latex hides 
/usr/share/emacs/site-lisp/auctex/latex
/usr/local/share/emacs/24.1.50/site-lisp/auctex/tex hides 
/usr/share/emacs/site-lisp/auctex/tex
/usr/local/share/emacs/24.1.50/site-lisp/auctex/texmathp hides 
/usr/share/emacs/site-lisp/auctex/texmathp
/usr/local/share/emacs/24.1.50/site-lisp/auctex/context-nl hides 
/usr/share/emacs/site-lisp/auctex/context-nl
/usr/local/share/emacs/24.1.50/site-lisp/auctex/tex-font hides 
/usr/share/emacs/site-lisp/auctex/tex-font
/usr/local/share/emacs/24.1.50/site-lisp/auctex/toolbar-x hides 
/usr/share/emacs/site-lisp/auctex/toolbar-x
/usr/local/share/emacs/24.1.50/site-lisp/auctex/tex-buf hides 
/usr/share/emacs/site-lisp/auctex/tex-buf
/usr/local/share/emacs/24.1.50/site-lisp/auctex/tex-fptex hides 
/usr/share/emacs/site-lisp/auctex/tex-fptex
/usr/local/share/emacs/24.1.50/site-lisp/auctex/bib-cite hides 
/usr/share/emacs/site-lisp/auctex/bib-cite
/usr/local/share/emacs/24.1.50/site-lisp/auctex/context-en hides 
/usr/share/emacs/site-lisp/auctex/context-en
/usr/local/share/emacs/24.1.50/site-lisp/auctex/tex-fold hides 
/usr/share/emacs/site-lisp/auctex/tex-fold
/usr/local/share/emacs/24.1.50/site-lisp/auctex/tex-bar hides 
/usr/share/emacs/site-lisp/auctex/tex-bar
/usr/local/share/emacs/24.1.50/site-lisp/auctex/context hides 
/usr/share/emacs/site-lisp/auctex/context
/usr/local/share/emacs/24.1.50/site-lisp/auctex/font-latex hides 
/usr/share/emacs/site-lisp/auctex/font-latex

Features:
(shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util
mail-prsvr mail-utils info cus-edit sh-script smie executable jka-compr
cc-langs cc-mode cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align
cc-engine cc-vars cc-defs vc-bzr add-log latexenc vc-git make-mode
preview prv-emacs byte-opt tex-buf noutline outline font-latex warnings
bytecomp byte-compile cconv latex tex-style tex flymake compile comint
ansi-color ring face-remap flyspell smart-quotes
auto-dictionary-autoloads c-eldoc-autoloads dictionary-autoloads
diff-git-autoloads dired-isearch-autoloads full-ack-autoloads
guess-style-autoloads kill-ring-search-autoloads magit-autoloads
mv-shell-autoloads tumble-autoloads http-post-simple-autoloads package
completing-help recentf tree-widget wid-edit uniquify paren server
savehist minibuf-eldef iswitchb icomplete autorevert desktop cus-start
cus-load ropemacs pymacs go-mode-load ispell advice advice-preload
yasnippet help-fns derived edmacro kmacro cl-macs gv easymenu assoc cl
cl-lib macroexp muse-autoloads emacs-goodies-el emacs-goodies-custom
emacs-goodies-loaddefs easy-mmode preview-latex tex-site auto-loads
user-site-loaddefs time-date tooltip ediff-hook vc-hooks lisp-float-type
mwheel x-win x-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list newcomment lisp-mode register page menu-bar rfn-eshadow
timer select scroll-bar 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 minibuffer loaddefs button faces
cus-face files text-properties overlay sha1 md5 base64 format env
code-pages mule custom widget hashtable-print-readable backquote
make-network-process dbusbind dynamic-setting system-font-setting
font-render-setting move-toolbar gtk x-toolkit x multi-tty emacs)

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