Switching spline_chest results in failed match (reproducable in all maya versions attempted - 2023.3.1, 2025, 2026)

[BenFreedman]

Repro:
Maya 2023.3 - Tested using 'start' tab to create basic rig with default settings
changed Spine_card to 'SplineChest'

try:mayaHooks.override.dagMenuProc.callback_customDagMenu('Spine04_ctrl')
except Exception:import traceback;print(traceback.format_exc())
switcher |main|Chest_controls|Chest_main_space|Chest_main_align|Chest_main|Chest_FKIK_SWITCH.IkSwitch Chest_main

Also unable to successfully switch spline_chest in previously functioning rigs.

Possibly (?) related issue given by Fossil Anim Tools Switcher concerning spline_chest:

switcher |main|Chest_controls|Chest_main_space|Chest_main_align|Chest_main|Chest_FKIK_SWITCH.IkSwitch Chest_main
# Error: No valid objects supplied to 'xform' command.
# # Traceback (most recent call last):
# #   File "C:\Program Files\Autodesk\Maya2023\Python\lib\site-packages\pymel\internal\factories.py", line 855, in callback
# #     res = origCallback(*newargs)
# #   File "C:\Program Files\Autodesk\Maya2023\Python\lib\site-packages\pymel\internal\factories.py", line 813, in __call__
# #     return self.func(*self.args, **self.kwargs)
# #   File "C:\Users/benfr/Documents/maya/scripts\fossilAnimTools\animSwitcherGui.py", line 212, in doIkFkSwitch
# #     fossil.kinematicSwitch.multiSwitch([obj], start, end)
# #   File "C:\Users/benfr/Documents/maya/scripts\pdil\tool\fossil\kinematicSwitch.py", line 92, in multiSwitch
# #     animStateSwitch(targetLeads, start, end, spaces={}, key=key)
# #   File "C:\Users/benfr/Documents/maya/scripts\pdil\tool\fossil\kinematicSwitch.py", line 251, in animStateSwitch
# #     harvestValues[lead][t] = harvestFunc[lead]( prep[lead] )
# #   File "C:\Users/benfr/Documents/maya/scripts\pdil\tool\fossil\rigging\splineChest.py", line 427, in harvest
# #     'extraFk': util.worldInfo(data['extraFk'][0]) if data['extraFk'] else None,
# #   File "C:\Users/benfr/Documents/maya/scripts\pdil\tool\fossil\rigging\_util.py", line 871, in worldInfo
# #     return [xform(obj, q=True, ws=True, t=True), xform(obj, q=True, ws=True, ro=True)]
# #   File "C:\Program Files\Autodesk\Maya2023\Python\lib\site-packages\pymel\internal\pmcmds.py", line 217, in xform_wrapped
# #     res = new_cmd(*new_args, **new_kwargs)
# # RuntimeError: No valid objects supplied to 'xform' command.

[BenFreedman]

Was experimenting with in Claude to see if I could narrow down the source of the issue and fix it. I think these changes prevented the issue from manifesting, but I'll have to dig in further and attempt to validate these as actual fixes to this problem.

I still end up with a situation when I build a chain with N number of joints, the Chest_Bend joint always gets placed at the end of that chain. (The workaround bieng to only make 1 joint above the ribcage base. Might be ideal to have an option in the module settings for SplineChest to set which index in the card the chest bend gets applied.

---

Three fixes applied:

splineChest.py:399-401 — activator.prep() now filters None from the children list, so BPJoints without a connected realJoint (e.g. tip joints) are skipped. This prevents worldInfo(None) from silently reading Maya's active selection and incorrectly placing Chest_bend at the selected FK joint.

nodeApi.py:2316 — getOtherMotionType() now returns None early when _outputAttr() returns None, preventing the AttributeError: 'NoneType' object has no attribute 'ik' crash on line 2323.

kinematicSwitch.py:71 — multiSwitch() now filters None from currentLeads in case node.leadController() returns None for any of the input objects, avoiding a crash on line 72.