Update deprecated MAV_TYPE enum for tailsitter

[Dennis-Johnson]

Hi,

This fixes #571.

With latest Pymavlink (master), the mavgen step works, but on trying to import mavutil, I get this error.

It seems that these two enums were changed, but weren't reflected in mavutil.py

• MAV_TYPE_VTOL_TAILSITTER_QUADROTOR was previously MAV_TYPE_VTOL_QUADROTOR
• MAV_TYPE_VTOL_TAILSITTER_DUOROTOR was previously MAV_TYPE_VTOL_DUOROTOR

I believe there is still a reference to the old enum name in Swift generator tests pymavlink/generator/swift/Tests/MAVLinkTests/Testdata/common.xml, but I haven't run that locally.

[peterbarker]

This would break ArduPilot's CI as we have not adopted the name-change into ardupilot/mavlink.

@hamishwillee what process was gone through to ensure renaming this enumeration entry would be smooth? i.e. MAV_TYPE_VTOL_QUADROTOR -> MAV_TYPE_VTOL_TAILSITTER_QUADROTOR ?

I'm not actually sure the rename is actually valid - the description does not precluse the use of MAV_TYPE_VTOL_DUOROTOR for belly-sitters as well as tailsitters.

[hamishwillee]

So it was discussed with @auturgy @DonLakeFlyer @meee1 both in mavlink/mavlink#1818 and also offline. The reasoning for the change is mostly here: mavlink/mavlink#1808 (comment)

• the description does not precluse the use of MAV_TYPE_VTOL_DUOROTOR for belly-sitters as well as tailsitters.

W.r.t. there is no such thing. Though note that I see https://mavlink.io/en/messages/minimal.html#MAV_TYPE_VTOL_TAILSITTER is misdocumented in the description to mention that removed concept. It should say MAV_TYPE_VTOL_TAILSITTER_DUOROTOR.

For a two rotor bellysitter you'd have to use MAV_TYPE_VTOL_FIXEDROTOR or a more specific MAV_TYPE_VTOL_FIXEDROTOR_DUO_ROTOR or similar. If that is invalid then yes, more thinking needed.

[peterbarker]

I've created a PR with an alternative approach here: #898

That will let mavutil.py work with both old and new message definitions.

Why has this only just now become a problem? It looks like these renames happened quite some time ago, which should have led to the mavutil.py AttributeErrors?!?