IMHO getargs(), getargspec(), getfullargspec() should be deprecated in favor of signature() which is future-proof. But Nick Coghlan undeprecated these functions in 2017 https://bugs.python.org/issue20438 whereas these were deprecated since 2015. I didn't understand the subtle issues. That's why I asked Pablo to open a separated issue, to get Nick and others involved to get the context.

My proposal was to raise an exception if the input function has positonal arguments. There is good way to fix these legacy functions, their design cannot be extended, whereas signature() is fine.