The sphgeom pybind11 wrappers have many instances of wrapped functions returning a unique pointer by releasing it just before returning it. Removing the call to .release() causes segfaults in all cases I tried except when it appears in the first function in a pickle wrapper (the one that appears on the Python side as __getstate__). I find this very surprising because the seemingly identical function encode() does segfault if .release() is removed.

Pim Schellart [X] asked me to file this ticket to figure out what's going on and remove the calls to .release() if possible.