[xmonad] Bug in program depends on number of tiled windows

[Wirt Wolff]

Excerpts from John Jumper's message of Sun Mar 11 22:21:16 -0600 2012:
> On Sun, Mar 11, 2012 at 8:01 PM, Brandon Allbery <allbery.b at gmail.com> wrote:
> 
> I looked at the documentation for x11() in R, and the default is to
> use type="X11".  If I install the Cairo library 1.5_1 for R and launch
> two CairoX11 plots, I get a segfault whenever I resize.  I will
> probably file this as a bug report with the R developers.  The
> segfault should be much easier to track down that drawing bugs.
> 
> gdb output (using R -d gdb):
> > library('Cairo'); CairoX11() ; CairoX11()
> >
> Program received signal SIGSEGV, Segmentation fault.
> 0x009f6704 in Rcairo_backend_resize (be=0xceb0, width=570, height=296)
> at cairotalk.c:1025
> 1025            if (!be || !be->dd) return;
> 
> I do not know if this has been reproduced with other tiling window managers.
> 

I also get segfaults using the Cairo CRAN library. Since R gave the
message 'memory not mapped' I suspected pax kernel protection might be
causing this. However, CairoX11() still segfaults when creating the
second graphics device, even after disabling all pax protections on
library/Cairo/libs/Cairo.so. It looks to me, though, that the built-in
X11.options(type='cairo') provides everything the Cairo library
does, so the Cairo package may be obsolete at this point.

The same drawing problems occur using R built without cairographics or
tk support (always uses Xlib devices), and using R built with cairo
support, i.e. X11.options(type='cairo').

I have verified that the same broken drawing occurs in i3 and in dwm,
even including the unpredictable results when toggling to and from
fullscreen or empty workspaces. So this isn't xmonad specific.

Best regards,
wmw