Provide support for yaml constructors !degrees and !radians

[rhaschke]

Addresses #251. @gavanderhoorn, please review.

[gavanderhoorn]

This is 💯 again @rhaschke.

My intention with #251 was not to come up with more work for you, but I'm of course very happy you decided to implement it.

I'll run some tests and let you know.

[gavanderhoorn]

This works for me 👍

thanks for adding this @rhaschke.

[gavanderhoorn]

Do I understand the code correctly when I say !radians appears to support "arbitrary expressions", while !degrees doesn't?

[rhaschke]

Do I understand the code correctly when I say !radians appears to support "arbitrary expressions", while !degrees doesn't?

Yes, that's what I copied from ros_param. Do you want to change this?

[gavanderhoorn]

Yes, that's what I copied from ros_param. Do you want to change this?

We should probably keep the same restrictions as in rosparam, so I would vote to keep it as-is.

Only thing to make sure perhaps is the eval(..) there: does it open up xacro to security issues? Should we limit / sanatise something perhaps?

[rhaschke]

Indeed, we should restrict eval() to our limited set of functions...

[gavanderhoorn]

@rhaschke: just submitted ubi-agni#4, which adds some (primitive) testing to the safe(r) eval(..) functionality when used in the yaml ctors.

[gavanderhoorn]

Thanks @rhaschke 👍

[gavanderhoorn]

@rhaschke: would you have time to release a new version of xacro which includes this change?

[rhaschke]

Done: ros/rosdistro#26352

[gavanderhoorn]

@rhaschke: I'm not sure I remember your syncing/back-porting policy between branches here.

Would it be possible to get this in Noetic as well?

[rhaschke]

Sure. I will prepare a new release later this evening.

[rhaschke]

Done: ros/rosdistro#26945

[gavanderhoorn]

Thanks @rhaschke 👍

[Briancbn]

Will this be merged into foxy release? I have to merge this to get the melodic-devel-staging urdf models working in ROS2.

[rhaschke]

@Briancbn: Sure. Do you mind preparing a merge PR? This would help to speed up the process.

[Briancbn]

@rhaschke could you help review the PR? thanks.

[rhaschke]

#259 is on my todo list. But there is just too much other work...