Might as well, since we already need to find this to calculate stack
info.
I've been considering adding -z/--depth to these scripts as well, but
that would require quite a bit more work. It's probably not worth the
added complexity/headache. Depth termination would need to happen on the
javascript side, and we'd still need cycle detection anyways.
But an error code is easy to add.
50e22ac690