23.0.60; Disabled undo

[Bill Wohler]

An MH-E user reported that when he sends mail with MH-E in CVS Emacs, he
can't undo. I was able to reproduce the bug and distill the problem down
to the following:

(defun disabled-undo-bug ()
  (interactive)
  (pop-to-buffer "draft")

  ;; Uncomment any one of the next three lines to allow undo.
  (insert-file-contents "/etc/motd")
  (goto-char (point-max))
  (insert-file-contents "/etc/motd")

  (message "Now, try to undo"))

If you run `M-x disabled-undo-bug' followed by `C-_' (`undo'), you get
the message "No further undo information". Undo works in Emacs 22 however.

If you fix this, can you please ack so that I can let my user know.
Thank you.


In GNU Emacs 23.0.60.1 (i686-pc-linux-gnu, GTK+ Version 2.12.5)
 of 2008-02-18 on olgas
Windowing system distributor `The X.Org Foundation', version 11.0.10300000
configured using `configure  'CFLAGS=-g''

Important settings:
  value of $LC_ALL: C
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: nil
  default-enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
C-x <return> m M-x m h - s m a i l <return> SPC C-_ 
C-h <backspace> C-c C-q SPC M-x r e p o r t - e m a 
<return>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Source file `/usr/local/src/mh-e/src/emacs/lisp/mh-e/mh-comp.el' newer than 
byte-compiled file
nmh 1.2 installed as MH variant
Composing a message...
Wrote /home/wohler/var/mail/drafts/4
Source file `/usr/local/src/mh-e/src/emacs/lisp/mh-e/mh-letter.el' newer than 
byte-compiled file
Type C-c C-c to send message, C-c ? for help
undo-start: No undo information in this buffer
Kill draft message? (y or n) 

-- 
Bill Wohler <address@hidden>  http://www.newt.com/wohler/  GnuPG ID:610BD9AD