bug#12338: 24.2.50; Error during redisplay (apropos which-function-mode?)

bug#12338: 24.2.50; Error during redisplay (apropos which-function-mode?)

[Jambunathan K]

My message buffer is getting populated with these messages

,----
|     Error during redisplay: (eval (replace-regexp-in-string "%" "%%"
|     (gethash (selected-window) which-func-table which-func-unknown)))
|     signaled (wrong-type-argument arrayp nil)
`----

I have following configs that concerns `which-function-mode'

,----
| 2 matches for "which" in buffer: .emacs
|      84: '(which-function-mode t))
|     111: '(which-func ((t (:inherit font-lock-function-name-face))))
`----

Can someone remove these messages or fix underlying problem?

I can narrow it down when I have sometime.  Documenting the issue for
now.


In GNU Emacs 24.2.50.12 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2012-09-03 on debian-6.05
Bzr revision: 109861 eggert@cs.ucla.edu-20120902171035-7mzihil3xd6bjfiy
Windowing system distributor `The X.Org Foundation', version 11.0.10707000
Important settings:
  value of $LANG: en_IN
  locale-coding-system: iso-latin-1-unix
  default enable-multibyte-characters: t

bug#12338: 24.2.50; Error during redisplay (apropos which-function-mode?)

[Eli Zaretskii]

> From: Jambunathan K <kjambunathan@gmail.com>
> Date: Mon, 03 Sep 2012 02:28:37 +0530
> 
> 
> My message buffer is getting populated with these messages
> 
> ,----
> |     Error during redisplay: (eval (replace-regexp-in-string "%" "%%"
> |     (gethash (selected-window) which-func-table which-func-unknown)))
> |     signaled (wrong-type-argument arrayp nil)
> `----
> 
> I have following configs that concerns `which-function-mode'
> 
> ,----
> | 2 matches for "which" in buffer: .emacs
> |      84: '(which-function-mode t))
> |     111: '(which-func ((t (:inherit font-lock-function-name-face))))
> `----
> 
> Can someone remove these messages or fix underlying problem?

The messages cannot be removed: this is the only way to signal an
error that happens during redisplay, without wedging Emacs.  That's
because displaying an error message in the normal way re-enters
redisplay, which will again signal an error, ad nauseam.

As you can see in which-func.el, the expression being evaluated is
which-func-current, which is part of which-func-format.  Hopefully,
this is enough to find the culprit.  (I don't see the error messages
if I just enable which-func-mode in 'emacs -Q".)

bug#12338: Status: 24.2.50; Error during redisplay (apropos which-function-mode?)

[Jambunathan K]

See http://lists.gnu.org/archive/html/emacs-devel/2012-10/msg00353.html

bug#12338: Status: 24.2.50; Error during redisplay (apropos which-function-mode?)

[Michael Heerdegen]

Jambunathan K <kjambunathan@gmail.com> writes:

> See
> http://lists.gnu.org/archive/html/emacs-devel/2012-10/msg00353.html

I can confirm that this patch fixes the bug.  Please install.

BTW, here is a recipe to reproduce this bug with emacs -Q in the
*scratch* buffer:

1. M-: (progn
         (switch-to-buffer "*scratch*")
         (which-func-mode)
         (goto-char (point-max))
         (insert "(defun test (x) 1)")
         (setq pop-up-windows t)
         (display-buffer "*Messages*"))

2. Move point into the comment at the beginning of *scratch*.  You get
the message (over and over):

Error during redisplay: (eval (replace-regexp-in-string "%" "%%"
(gethash (selected-window) which-func-table which-func-unknown)))
signaled (wrong-type-argument arrayp nil)


Thanks,

Michael.

bug#12338: Status: 24.2.50; Error during redisplay (apropos which-function-mode?)

[Stefan Monnier]

>> See http://lists.gnu.org/archive/html/emacs-devel/2012-10/msg00353.html
> I can confirm that this patch fixes the bug.  Please install.

Thank you, installed,


        Stefan