Re: set-window-vscroll causes infinite loop in redisplay

[storm@cua.dk (Kim F. Storm)]

storm@cua.dk (Kim F. Storm) writes:

> This is with CVS head on GNU/Linux under X.
> 
> 1) start emacs
> 
> emacs -q
> 
> 2) get rid of splash screen
> 
> RET
> 
> 3) In scratch buffer, enter:
> 
> (set-window-vscroll nil 0.5) C-j
> 
> 4) (try to) move cursor to the first (partially visible) line.
> 
> C-p C-p C-p C-p C-p C-p C-p C-p
> 
> 5) emacs loops.
> 
> 
> 
> The following patch fixes this.  I'll install it tomorrow unless
> someone finds a better fix.

I think the following fix is slightly better -- it retries the
recenter if vscroll was enabled.  But it probably doesn't make much
visible difference...

Index: xdisp.c
===================================================================
RCS file: /cvsroot/emacs/emacs/src/xdisp.c,v
retrieving revision 1.807
diff -c -r1.807 xdisp.c
*** xdisp.c	24 Feb 2003 07:57:55 -0000	1.807
--- xdisp.c	24 Feb 2003 14:46:05 -0000
***************
*** 10822,10827 ****
--- 10822,10835 ----
  
    if (!make_cursor_line_fully_visible (w))
      {
+       /* If vscroll is enabled, disable it and try again.  */
+       if (w->vscroll)
+ 	{
+ 	  w->vscroll = 0;
+ 	  clear_glyph_matrix (w->desired_matrix);
+ 	  goto recenter;
+ 	}
+       
        /* If centering point failed to make the whole line visible,
  	 put point at the top instead.  That has to make the whole line
  	 visible, if it can be done.  */


-- 
Kim F. Storm <storm@cua.dk> http://www.cua.dk