Children of ohphyd-async devices are not resolved properly in plans

[canismarko]

Consider the following plan:

{
    "name": "mv", 
    "args": ["sim_motor_2.user_setpoint", -20]
}

If sim_motor_2 is a device created during the startup script with the following:

from ophyd_async.epics.motor import Motor

with init_devices():
    sim_motor_2 = Motor("25idc:simMotor:m2", name="sim_motor_2")

then I would expect this description to result in:

RE(mv(sim_motor_2.user_setpoint, -20))

However I get the following exception: AttributeError: 'str' object has no attribute 'parent'

In the existing plans and devices YAML file I see:

  sim_motor_2:
    classname: Motor
    is_flyable: true
    is_movable: true
    is_readable: true
    module: ophyd_async.epics.motor

However, there are no components. An equivalent device using ophyd produces the following:

  sim_motor_2:
    classname: EpicsMotor
    components:
      acceleration:
        classname: EpicsSignal
        is_flyable: false
        is_movable: true
        is_readable: true
        module: ophyd.signal
      ...

Best I can tell, this causes _is_object_name_in_list(v) to fail and the device does not get resolved from it's name "sim_motor_2.user_setpoint" to the actual device to be moved.

Looking ahead, the following line should call _get_nspace_object. I'm not sure if this will work either, since this function relies on the device having component_names, which ophyd-async devices don't have.

[coretl]

This is the ophyd-async version of component_names:
https://github.com/bluesky/ophyd-async/blob/5b9e43bf0a877603a115ae0f4a1a9730bc8f1ed3/src/ophyd_async/core/_device.py#L107-L111

An iterator of (attr_name, attr) tuples

Discussion on turning it into a protocol:
bluesky/bluesky#1601

[dmgav]

I will look into this issue (and #328) shortly. This should not be difficult to fix.

[canismarko]

Thanks, @dmgav!