Handling underlying exceptions in ExtensionArrayOpsMixin

[TomAugspurger]

I'm growing to dislike the try / except to wrap the results of a binop. That's what hid #22930.

I wonder, is it possible for EA authors to annotate which ops form an algebra for their Extension type, so that we can know ahead of time whether the result should be wrappe? Something like

_ops_return_ea = {
    '__add__', '__sub__', ...
}

and if the op name is in those, then we attempt to wrap the result, but don't catch any errors? If the op name isn't in those then we return an ndarray?

The thing that would ruin this is if there were legitimate cases where whether or not the result can be wrapped depends on the value, rather than the type. Can we think of any of those?

cc @Dr-Irv

[jorisvandenbossche]

It is only done like that for the ScalarOpsMixin, correct?
So I understand your point, it's certainly brittle, but it is also maybe not that worth adding too much complexity for it. If you want to be sure what is returned, you can always add the operations yourself.

[TomAugspurger]

Right, this is just for ScalarOpsMixin. Let's ignore it for now.

[Dr-Irv]

Just to add to the discussion @TomAugspurger, I did it this way because I have ops that take two EA's of the same type and produce an EA of a different type. In some sense, divmod is like that.