check device_setup matches run_once

[hartytp]

Is there any good use case for device_setup implementations not to be kernels? If not, shall we add a build-time check that device_setup is a kernel to help spot errors. Otherwise a missing decorator can lead to long run times in a way that can be slightly non-trivial to debug.

Is there any good use case for one of device_setup and run_once to be a kernel but not the other? If not, shall we add a run-time check that enforces this? Otherwise a missing decorator can lead to long run times in a way that can be non-trivial to debug.

This check should presumably be applied recursively to all subfragment device_setups...

FWIW it also feels conceptually wrong to me to have a "device setup" which does not run on the core device. Bit of a misnomer?

[hartytp]

One thing that would have complicated the implementation of this check was dealing with Fragments which were never intended to be setup / torn down as part of the main experiment. Since 2f9e36f added an explicit way of handling that this is no longer an issue AFAICT.