px4.add_roll_pitch_yaw doesn't work with DatabaseULog.get_dataset

[Herman Øie Kolden]

When I call px4.add_roll_pitch_yaw(), I expect e.g. 'vehicle_attitude.roll' to be retrievable from uog.get_dataset('vehicle_attitude'). However, since the former modifies the ULog object directly and the latter gets the dataset from the DB, the 'roll' field is not found.

[Herman Øie Kolden]

IMO we should refactor this to avoid direct object modifications. Maybe e.g. adding preprocessors in DatabaseULog.save(), so that roll/pitch/yaw is always added.

[Beat Küng]

I would rather go the other way and make sure that post processing works, otherwise there's inconsistent behavior between the file and DB, in terms of what data is stored.
The problems I see are:

• get_dataset always loads from DB when called repeatedly for the same dataset
• potentially lazy loading and add_roll_pitch_yaw does not call get_dataset to fill in the data

That would still allow you to do the modifications before calling save().