ediff and svn cause xemacs to crash

[Vijay Ramachandran]

Hello. I recently upgraded ubuntu to 10.04, which installs xemacs
21.4.22:

XEmacs 21.4 (patch 22) "Instant Classic" [Lucid] (i486-linux-gnu,
Mule) of Tue Jul 14 2009 on vernadsky

When I try to ediff an svn version controlled file, xemacs crashes
with the following message and lisp backtrace. The version of psvn.el
is

;;; psvn.el --- Subversion interface for emacs
;; Copyright (C) 2002-2009 by Stefan Reichoer

;; Author: Stefan Reichoer <ste...@xsteve.at>
;; $Id: psvn.el 40299 2009-10-29 19:38:54Z xsteve $

xemacs: ../../src/xcb_io.c:249: process_responses: Assertion `(((long)
(dpy->last_request_read) - (long) (dpy->request)) <= 0)' failed.

Fatal error (6).

Your files have been auto-saved.
Use `M-x recover-session' to recover them.

Your version of XEmacs was distributed with a PROBLEMS file that may
describe
your crash, and with luck a workaround. Please check it first, but do
report
the crash anyway. Please report this bug by invoking M-x report-emacs-
bug,
or by selecting `Send Bug Report' from the Help menu. If necessary,
send
ordinary email to `xemac...@xemacs.org'. *MAKE SURE* to include
the XEmacs
configuration from M-x describe-installation, or equivalently the file
Installation in the top of the build tree.

*Please* try *hard* to obtain a C stack backtrace; without it, we are
unlikely
to be able to analyze the problem. Locate the core file produced as a
result
of this crash (often called `core' or `core.<process-id>', and located
in
the directory in which you started XEmacs or your home directory), and
type

gdb /usr/bin/xemacs core

then type `where' at the debugger prompt. No GDB on your system? You
may
have DBX, or XDB, or SDB. (Ask your system administrator if you need
help.)
If no core file was produced, enable them (often with `ulimit -c
unlimited'
in case of future recurrance of the crash.

Lisp backtrace follows:

# (unwind-protect ...)
old-call-process-internal("svn" nil t nil "status" "-v"
"mail_notify.py")
apply(old-call-process-internal "svn" nil t nil ("status" "-v"
"mail_notify.py"))
# bind (args display buffer infile program)
call-process-internal("svn" nil t nil "status" "-v"
"mail_notify.py")
apply(call-process-internal "svn" nil t nil ("status" "-v"
"mail_notify.py"))
# bind (coding-system-for-read args displayp buffer infile program)
call-process("svn" nil t nil "status" "-v" "mail_notify.py")
apply(call-process "svn" nil t nil ("status" "-v" "mail_notify.py"))
# bind (buffer-undo-list exec-path process-environment w32-quote-
process-args squeezed inhibit-read-only status)
# (unwind-protect ...)
# bind (flags file command okstatus buffer)
ad-Orig-vc-do-command(t 0 "svn" "/home/vijayr/wt/b2b/b2b/lib/
mail_notify.py" "status" "-v")
apply(ad-Orig-vc-do-command t 0 "svn" "/home/vijayr/wt/b2b/b2b/lib/
mail_notify.py" ("status" "-v"))
(setq ad-return-value (apply (quote ad-Orig-vc-do-command) buffer
okstatus command file flags))
(if (or (and ... ...) (and ... ...)) (setq ad-return-value
(apply ... buffer okstatus command file flags)) (setq ad-return-value
(apply ... buffer okstatus command file flags)))
# bind (file)
(let ((file ...)) (if (or ... ...) (setq ad-return-value ...) (setq
ad-return-value ...)))
# bind (ad-return-value)
(let (ad-return-value) (let (...) (if ... ... ...)) ad-return-value)
# bind (flags file command okstatus buffer)
vc-do-command(t 0 "svn" "/home/vijayr/wt/b2b/b2b/lib/mail_notify.py"
"status" "-v")
apply(vc-do-command t 0 "svn" "/home/vijayr/wt/b2b/b2b/lib/
mail_notify.py" ("status" "-v"))
# bind (flags file okstatus buffer)
vc-svn-command(t 0 "/home/vijayr/wt/b2b/b2b/lib/mail_notify.py"
"status" "-v")
# (unwind-protect ...)
# (unwind-protect ...)
# bind (temp-buffer localp file)
vc-svn-state("/home/vijayr/wt/b2b/b2b/lib/mail_notify.py")
(svn-status-interprete-state-mode-color (vc-svn-state buffer-file-
name))
(svn-status-update-state-mark (svn-status-interprete-state-mode-
color (vc-svn-state buffer-file-name)))
(if (and buffer-file-name (svn-status-in-vc-mode\?)) (svn-status-
update-state-mark (svn-status-interprete-state-mode-color ...)))
(when (and buffer-file-name (svn-status-in-vc-mode\?)) (svn-status-
update-state-mark (svn-status-interprete-state-mode-color ...)))
svn-status-update-modeline()
# (unwind-protect ...)
# bind (ad-return-value)
ediff-refresh-mode-lines()
# (unwind-protect ...)
# bind (control-frame control-buf no-rehighlight)
ediff-recenter(no-rehighlight)
# bind (ediff-current-difference no-recenter flag n)
ediff-unselect-and-select-difference(5)
# bind (n non-clash-skip skip-changed regexp-skip arg)
ediff-next-difference(1)
# bind (command-debug-status)
call-interactively(ediff-next-difference)
# (condition-case ... . error)
# (catch top-level ...)

Please help!

thanks,
Vijay