getChildren() fails in cases where attributeQuery(listChildren=True) succeeds

[kimonmatara]

Summary

getChildren() fails on some compounds. In those cases, children can be retrieved via attributeQuery(listChildren=True) instead.

Example

Under Maya 2023.1, Python 3.9.7 (tags/v3.9.7:1016ef3, Aug 30 2021, 20:19:38) [MSC v.1929 64 bit (AMD64)]:

import pymel.core as p

node = p.spaceLocator().getShape()
compound = node.attr('worldPosition')
compound.getChildren() # Fails with:
# ...general.py line 4376: (kFailure): Data type is not valid here

The most reliable workaround is to use attributeQuery() instead:

childNames = p.attributeQuery('worldPosition', node=node, listChildren=True)
children = [node.attr(childName) for childName in childNames]

Re-instantiating via Attribute works, but not always:

compound = str(compound)
compound = p.PyNode(compound)
compound.getChildren() # Succeeds, but not always

This doesn't happen on all compounds:

persp = p.PyNode('persp')
persp.attr('translate').getChildren() # Succeeds

[kimonmatara]

Scrap this--this is because worldPosition is a multi + compound, and getChildren() has always failed on non-indexed multi-compounds.