What should a decorator do if an attribute already exists?

[Stephen Hansen]

On Tue, May 10, 2016, at 08:45 AM, Steven D'Aprano wrote:
> I have a decorator that adds an attribute to the decorated function:
> [...]
> My question is, what should I do if the decorated function already has an
> instrument attribute?
> 
> 1. raise an exception?

This. Your decorator should, IMHO, treat the attribute as private data,
and if something else is using the same thing, something has clearly
gone wrong and raising the error early and clearly is right.

-- 
Stephen Hansen
  m e @ i x o k a i . i o