Subject: bug#13438: /srv/bzr/emacs/emacs-24 r111196: * imenu.el (imenu-default-create-index-function): Remove useless

From: Glenn Morris <[email-masked]>
Date: Fri, 25 Jan 2013 03:34:53 -0500

>> Why is this issue (apparently) only seen in Python mode

Answering my own question, it happens in any mode that sets
imenu-prev-index-position-function and
imenu-extract-index-name-function, but there are very few of those.

Eg prolog mode. With buffer contents:

------
fac(0,1).
fac(N,F) :- N > 0, M is N - 1,
       fac(M,Fm), F is N * Fm.
------

and point at point-min, switching to prolog-mode causes the same issue.

How about taking the more cautious approach with:

(when (and (= pos (point))
           (not (bobp)))
   (error "Infinite loop... ))

(IIUC, this was actually the suggestion in
http://lists.gnu.org/archive/html/emacs-devel/2013-01/msg00510.html ?)