Blender asset import creates a new bone for every object parented to same bone

[smix8]

Godot version

c3ed7af

System information

Windows 10

Issue description

When importing a Blender 3D asset the Godot asset importer creates a new bone and a new BoneAttachment3D for each object that was parented to a skeleton bone, e.g. each mesh item. Even if this behavior is wanted there is imo a bug when 100 objects are parented all to the very same bone in Blender the Godot importer adds +100 additional bones instead of just one extra bone.

This can result in a very excessive amount of extra bones on complex skeletons with many attachments for e.g. character customization. As mentioned in related #75915 having so many extra bones is slow to work with and consumes performance for mostly nothing.

Godot 3 did not add extra bones for each bone attachment but this was apparently changed to solve other bugs with bone index shuffling like #64512 and #61641.

Steps to reproduce

• Open the attached Blender test file (was made with Blender 3.40)
• See both meshes are parented to the same bone.
• Copy blend file to Godot and let importer run.
• See that Godot created two new extra bones that did not exist in the original skeleton.

Minimal reproduction project

BlenderTestFile.zip

[TokageItLab]

Was this behavior added at some point in the 4.0 alpha? This may be tough since it is old, but can you identify the commit or PR that added this in Blame or Bisect?

[smix8]

Consider there are duplicated issues for this from 4.0.2 and my issues is even older it was somewhere in Godot 4.0 alpha. Likely from the begin with the GLTF importer rework as Godot 3 does not have the problem.