Fix inheriting from Sendable

- initSendable needs to be passed a reference
- The SendableRegistry needs to be cleared on shutdown to ensure that ntcore doesn't call into python

Author: virtuald

gen/Sendable.yml

@@ -8,3 +8,8 @@ classes:
     shared_ptr: true
     methods:
       InitSendable:
+        virtual_xform: |
+          [&](py::function fn) {
+            auto builderHandle = py::cast(builder, py::return_value_policy::reference);
+            fn(builderHandle);
+          }

wpiutil/src/main.cpp

@@ -4,11 +4,22 @@
 void setup_stack_trace_hook(py::object fn);
 void cleanup_stack_trace_hook();
 
+namespace wpi::impl {
+void ResetSendableRegistry();
+} // namespace wpi::impl
+
 RPYBUILD_PYBIND11_MODULE(m) {
   initWrapper(m);
 
   static int unused;
-  py::capsule cleanup(&unused, [](void *) { cleanup_stack_trace_hook(); });
+  py::capsule cleanup(&unused, [](void *) {
+    {
+      py::gil_scoped_release unlock;
+      wpi::impl::ResetSendableRegistry();
+    }
+
+    cleanup_stack_trace_hook();
+  });
 
   m.def("_setup_stack_trace_hook", &setup_stack_trace_hook);
   m.add_object("_st_cleanup", cleanup);