[Python-Dev] weak refs in descriptors (http://bugs.python.org/issue17950) (original) (raw)

Joao S. O. Bueno jsbueno at python.org.br
Mon May 13 15:35:00 CEST 2013

On 13 May 2013 10:20, Maciej Fijalkowski <fijall at gmail.com> wrote:

On Mon, May 13, 2013 at 1:49 PM, Kristján Valur Jónsson <kristjan at ccpgames.com> wrote:

Hello python-dev.

I‘m working on a patch to remove reference cycles from heap-allocated classes: http://bugs.python.org/issue17950 Part of the patch involves making sure that descriptors in the class dictionary don’t contain strong references to the class itself. This is item 2) in the defect description. I have implemented this via weak references and hit no issues at all when running the test suite. But I’d like to ask the oracle if there is anything I may be overlooking with this approach? Any hidden problems we might encounter?

K Hi Kristjan The strong reference there is a feature. Descriptors keep the class alive if somehow the class disappears and the descriptor itself does not. Please don't change language semantics (yes, this is a change in semantics), just because the test suite passes - I can assure you there are people doing convoluted stuff that expect this to work. +1 for it being an expected behavior.

So I think it would be a nice thing to write a test that breaks under this condition

js -><-

Cheers, fijal

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