bug#17324: 24.3.90; (wrong-type-argument number-or-marker-p nil) in redisplay--update-region-highlight

bug#17324: 24.3.90; (wrong-type-argument number-or-marker-p nil) in redisplay--update-region-highlight

[Nicolas Richard]

Hi,

I got the following error (but I can't reproduce it in a fresh session) :

Debugger entered--Lisp error: (wrong-type-argument number-or-marker-p nil)
  min(2623 nil)
  (let* ((pt (window-point window)) (mark (mark)) (start (min pt mark)) (end (max pt mark)) (new (funcall redisplay-highlight-region-function start end window rol))) (if (equal new rol) nil (set-window-parameter window (quote internal-region-overlay) new)))
  (if (not (region-active-p)) (funcall redisplay-unhighlight-region-function rol) (let* ((pt (window-point window)) (mark (mark)) (start (min pt mark)) (end (max pt mark)) (new (funcall redisplay-highlight-region-function start end window rol))) (if (equal new rol) nil (set-window-parameter window (quote internal-region-overlay) new))))
  (let ((rol (window-parameter window (quote internal-region-overlay)))) (if (not (region-active-p)) (funcall redisplay-unhighlight-region-function rol) (let* ((pt (window-point window)) (mark (mark)) (start (min pt mark)) (end (max pt mark)) (new (funcall redisplay-highlight-region-function start end window rol))) (if (equal new rol) nil (set-window-parameter window (quote internal-region-overlay) new)))))
  (save-current-buffer (set-buffer (window-buffer window)) (let ((rol (window-parameter window (quote internal-region-overlay)))) (if (not (region-active-p)) (funcall redisplay-unhighlight-region-function rol) (let* ((pt (window-point window)) (mark (mark)) (start (min pt mark)) (end (max pt mark)) (new (funcall redisplay-highlight-region-function start end window rol))) (if (equal new rol) nil (set-window-parameter window (quote internal-region-overlay) new))))))
  redisplay--update-region-highlight(#<window 3 on *Backtrace*>)
  #[0 "\300\242\204\n.\303\304 !\207\300\242<\204.

bug#17324: 24.3.90; (wrong-type-argument number-or-marker-p nil) in redisplay--update-region-highlight

[Stefan Monnier]

> I got the following error (but I can't reproduce it in a fresh session) :
> Debugger entered--Lisp error: (wrong-type-argument number-or-marker-p nil)
>   min(2623 nil)
[...]
>   redisplay--update-region-highlight(#<window 3 on *Backtrace*>)

I've been tracking down this problem for a while now, but can't seem to
find its source.  So I installed the patch below to work around it for now.


        Stefan


--- lisp/simple.el	2014-04-12 19:20:44 +0000
+++ lisp/simple.el	2014-04-23 12:50:59 +0000
@@ -4495,7 +4495,12 @@
 mode is enabled.  Usually, such commands should use
 `use-region-p' instead of this function, because `use-region-p'
 also checks the value of `use-empty-active-region'."
-  (and transient-mark-mode mark-active))
+  (and transient-mark-mode mark-active
+       ;; FIXME: Somehow we sometimes end up with mark-active non-nil but
+       ;; without the mark being set (e.g. bug#17324).  We really should fix
+       ;; that problem, but in the mean time, let's make sure we don't say the
+       ;; region is active when there's no mark.
+       (mark)))
 
 
 (defvar redisplay-unhighlight-region-function