https://bugs.freedesktop.org/show_bug.cgi?id=109524
--- Comment #7 from Ilia Mirkin imirkin@alum.mit.edu --- This patch should avoid the error being printed:
https://patchwork.freedesktop.org/patch/315751/
However I suspect that the calling code will continue to crash -- we return a NULL pointer, and I suspect that the caller expects this to be non-null.