[Python-Dev] @deprecated (was: Useful thread project for 2.5?) (original) (raw)

Guido van Rossum gvanrossum at gmail.com
Thu Mar 10 02:28:57 CET 2005

This is a recipe for disaster. Creating a new function from the old can have unwanted side effects, since you effectively change the object. For example, if someone is monkey patching this function, then the deprecation warning gets lost.

That's a rather extreme use case, and not one that IMO should block the @deprecated decorator from being used. I hope that monkey patching is rare enough that you shouldn't mind checking once a year of so if the thing you're monkey-patching might have been deprecated (in which case you shouldn't be monkey-patching it but instead rewrite your code to avoid it altogether).

In Zope 3's deprecation package, we have decided to put a special deprecation proxy around the module (instead of the function) and register a list of attribute names (note that it does not matter whether its a class, function or other type of object) that are deprecated. The advantage is that you get a deprecation warning just by looking up the object.

Yeah, but not everybody has Zope's proxying machinery.

I think you're overreacting.

-- --Guido van Rossum (home page: http://www.python.org/~guido/)

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