How does anyone on the stack above handle this error? i.e. what can be done programmatically to deal with it?

I claim this is far worse than panic in this case... you've now introduced a code path variant that folks above think is "legitimate" or caused by some input or something in the environment that could be changed to make it go away... but that's not the case here... the only thing that can be fixed is the code in question to not be in this region if the array length is 2 or less. It's a plain old "bug" and the only cure (other than more cowbell) is to modify source and recompile.