bug#17855: 24.3; Sluggish which-function-mode with specific Java code

[Kimmo Sipilä]

Precondition: A java source file (/tmp/foo.java) containing the
following function (use spaces - not tabs):

public void a(
    int b,
    int c,
    int d,
    int e,
    int f,
    int g,
    int h,
    int i,
    int j,
    int k // comment
    )
{
}

Start Emacs using 'emacs -Q' and enter the following:

C-x C-f /tmp/foo.java RET
M-x which-function-mode


Emacs freezes for a couple of minutes.


In GNU Emacs 24.3.1 (x86_64-pc-linux-gnu, GTK+ Version 3.8.2)
 of 2013-07-27 on roseapple, modified by Debian
Windowing system distributor `The X.Org Foundation', version 11.0.11405000
System Description:    Ubuntu 13.10

Configured using:
 `configure '--build' 'x86_64-linux-gnu' '--build' 'x86_64-linux-gnu'
 '--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib'
 '--localstatedir=/var/lib' '--infodir=/usr/share/info'
 '--mandir=/usr/share/man' '--with-pop=yes'
 
'--enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.3/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.3/site-lisp:/usr/share/emacs/site-lisp'
 '--with-crt-dir=/usr/lib/x86_64-linux-gnu' '--with-x=yes'
 '--with-x-toolkit=gtk3' '--with-toolkit-scroll-bars'
 'build_alias=x86_64-linux-gnu' 'CFLAGS=-g -O2 -fstack-protector
 --param=ssp-buffer-size=4 -Wformat -Werror=format-security -Wall'
 'LDFLAGS=-Wl,-Bsymbolic-functions -Wl,-z,relro'
 'CPPFLAGS=-D_FORTIFY_SOURCE=2''

Important settings:
  value of $LC_MONETARY: en_US.UTF-8
  value of $LC_NUMERIC: en_US.UTF-8
  value of $LC_TIME: fi_FI.UTF-8
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
  which-function-mode: t
  show-paren-mode: t
  iswitchb-mode: t
  shell-dirtrack-mode: t
  recentf-mode: t
  display-time-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

Recent input:
M-x r e p o <tab> r <tab> <return>

Recent messages:
Loading /var/cache/dictionaries-common/emacsen-ispell-default.el (source)...done
Loading debian-ispell...done
Loading /var/cache/dictionaries-common/emacsen-ispell-dicts.el (source)...done
Loading /etc/emacs/site-start.d/50dictionaries-common.el (source)...done
Loading /etc/emacs/site-start.d/50emacs-goodies-el.el (source)...done
Loading /etc/emacs/site-start.d/50gtk-doc-tools.el (source)...done
Loading /home/kisipila/.recentf...done
Cleaning up the recentf list...done (0 removed)
For information about GNU Emacs and the GNU system, type C-h C-a.
Making completion list...

Load-path shadows:
~/.emacs.d/site-lisp/bm hides /usr/share/emacs24/site-lisp/emacs-goodies-el/bm
/usr/share/emacs/24.3/site-lisp/debian-startup hides 
/usr/share/emacs/site-lisp/debian-startup
/usr/share/emacs24/site-lisp/dictionaries-common/ispell hides 
/usr/share/emacs/24.3/lisp/textmodes/ispell
/usr/share/emacs24/site-lisp/dictionaries-common/flyspell hides 
/usr/share/emacs/24.3/lisp/textmodes/flyspell

Features:
(shadow sort mail-extr emacsbug message rfc822 mml mml-sec mm-decode
mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader
sendmail rfc2047 rfc2045 ietf-drums mail-utils help-mode desktop
which-func imenu uniquify warnings paren iswitchb grep compile rx bm
edmacro kmacro cl-macs gv info cl tramp tramp-compat auth-source eieio
byte-opt bytecomp byte-compile cconv gnus-util mm-util mail-prsvr
password-cache tramp-loaddefs shell pcomplete comint ansi-color ring
format-spec advice help-fns cl-lib advice-preload recentf tree-widget
wid-edit easymenu server time emacs-goodies-el emacs-goodies-custom
emacs-goodies-loaddefs easy-mmode 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 macroexp 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)