Error when parenting an armature to another armature's bone

[HeCorr]

I'm trying to parent an armature to another armature's bone and it's throwing an error:

Python: Traceback (most recent call last):
  File "C:\Users\Henrique\AppData\Roaming\Blender Foundation\Blender\3.0\scripts\addons\dynamic_parent.py", line 251, in execute
    const = get_last_dymanic_parent_constraint(obj)
  File "C:\Users\Henrique\AppData\Roaming\Blender Foundation\Blender\3.0\scripts\addons\dynamic_parent.py", line 58, in get_last_dymanic_parent_constraint
    if not obj.constraints:
AttributeError: 'NoneType' object has no attribute 'constraints'

location: <unknown location>:-1

Blender version: 3.0.1 build dc2d18018171
Dynamic Parent version: 1.0.0

Here's a video demonstrating the issue:

2022-02-11.15-24-15.mp4

The current workaround is to parent the child armature to an empty directly and dynamically parent the empty to the main armature:

2022-02-11.15-26-04.mp4

...which is not the end of the world but I would rather not have to do that, specially when working with many child armatures.

[romanvolodin]

You have to select both armatures and switch into Pose Mode. Then DynamicParent will work.

[HeCorr]

But that requires me to have a root bone in the child armature, which in my case I don't.

It's possible to manually add a ChildOf constraint to the armature, so shouldn't it just work? Is there a limitation in Blender's API?

[romanvolodin]

You don't need any root bone. It should work as it is.

2022-02-13_00-55-20.mp4

[HeCorr]

What I meant by a root bone is a bone that all other bones are parented to.

The way you showed in the video I still need to parent a specific bone, not the armature object, which is what I want.

In my case I have two disconnected bones and I would have to parent both if I were to use your method (or modify the armature, creating a root bone whose other bones are statically parented to).

I still consider this a limitation and would like to see it implemented in the future if possible, otherwise you can close the issue.