When I create function spaces with a constrained domain with ghost_mode = shared_vertex I get a segmentation fault. Running with just one process and everything is fine with the periodic boundary condition.
Is this a known issue or something to be supported later on?
One argument is that you should never get a segmentation fault from the library, so this is a bug, which needs fixing, at least with an error message saying it is not supported. Have you looked through the bitbucket issues?