[Python-Dev] PEP 487 vs 422 (dynamic class decoration)

[PJ Eby]

On Fri, Apr 3, 2015 at 11:04 AM, Nick Coghlan <ncoghlan at gmail.com> wrote:
> Extending the descriptor protocol to include a per-descriptor hook that's
> called at class definition time sounds like a potentially nice way to go to
> me. While you *could* still use it to arbitrarily mutate the class object,
> it's much clearer that's not the intended purpose, so I don't see it as a
> major problem.

Just to be clear, mutating the class object was never the point for my
main use case that needs the PEP 422 feature; it was for method
overloads that are called remotely and need to be registered
elsewhere.  For some of my other use cases, adding metadata to the
class is a convenient way to do things, but classes are generally
weak-referenceable so the add-on data can be (and often is) stored in
a weak-key dictionary rather than placed directly on the class.