Re: Random "Regular expression too big"

[Alan Mackenzie <acm@muc.de>]

Hi, Rob!

On Mon, Jul 07, 2008 at 12:03:31PM -0700, Rob Emanuele wrote:
> Greetings,

> Every now and again I've been getting an error "Regular expression too
> big".  This seems to occur randomly.  Sometimes it can occur on startup
> and emacs never opens.  Other times emacs opens and these messages
> below are listed out.  Yet other times it'll happen in the middle of my
> work while I'm saving, setting the fontset, or doing some otherwise
> innocuous task.

Does it happen:
(i) a lot - so often that you can hardly get your work done;
(ii) sometimes - once or twice a week, but you're continually on edge
  about it.
(iii) once a blue moon?

Hopefull it's (i) or (ii).  :-)

A good thing to do would be to start your Emacs as

  emacs --debug-init

, and once you've started OK, do

  M-: (setq debug-on-error t)

.  One of these will generate a lisp stack dump when the error happens
again.

> This is with emacs:
> GNU Emacs 22.1.1 (x86_64-redhat-linux-gnu, GTK+ Version 2.12.5) of
> 2008-05-23 on xenbuilder2.fedora.redhat.com

> This will still happen even if I remove my .emacs and even if I remove
> /usr/share/emacs/site-lisp.

Hmmm...  That suggests that some other initialisation file is giving you
grief.  There's a list of these files on the page "Init File" in the
Emacs manual.  Try doing

M-x locate-library default

.  If this locates a default.el, the problem may be there.

> ("emacs" "production/main.cpp")
> Loading /usr/share/emacs/site-lisp/site-start.d/focus-init.el (source)...done
> Loading /usr/share/emacs/site-lisp/site-start.d/igrep-init.el (source)...done
> Loading /usr/share/emacs/site-lisp/site-start.d/php-mode-init.el (source)...done
> Loading /usr/share/emacs/site-lisp/site-start.d/po-mode-init.el (source)...done
> Loading /usr/share/emacs/site-lisp/site-start.d/rpm-spec-mode-init.el
> (source)...done
> For information about the GNU Project and its goals, type C-h C-p.
> Loading cc-mode...done
> File mode specification error: (invalid-regexp "Regular expression too big")

This error occurs in the function `normal-mode', which was in the course
of determining the major mode for the file you were trying to visit
(whatever that might be).  Seeing as how CC Mode has just been loaded,
this could well be a C, C++, ... file.

> Loading vc-svn...done
> Loading vc...done
> vc-svn-parse-status: Invalid regexp: "Regular expression too big"
> mouse-drag-region: Invalid regexp: "Regular expression too big" [2 times]
 byte-code: Beginning of buffer
> Error in menu-bar-update-hook: (invalid-regexp Regular expression too big)

> Thank you for any help fixing this or working around it!

You do seem to like big regular expressions rather a lot.  ;-)

Anyhow, please activate these things which will generate a stack dump.
That might well enable you to fix the problem yourself.  If not, post the
dump here.

> --Rob

-- 
Alan Mackenzie (Nuremberg, Germany).