Thank you, makes sense. This one has been bugging me every time I worked with descriptors.
I even had __set__ method in my Descriptor Base for class attributes, but never needed it so didn’t realise. > On 19 Oct 2023, at 12:09, Antoine Rozo <antoine.r...@gmail.com> wrote: > > Hi, > > The __get__ method of descriptors can be called at the class level (that's > how methods work) and in that case instance would be None, but owner will > always reference the current class. > > __set__ can only be called for instances on that class (`Cls.attr = ...` > would redefine the class-attribute and not call the descriptor), so instance > can never be None and owner is type(instance). > > Le jeu. 19 oct. 2023 à 09:45, Dom Grigonis <dom.grigo...@gmail.com > <mailto:dom.grigo...@gmail.com>> a écrit : > > > On 19 Oct 2023, at 10:27, dn via Python-ideas <python-ideas@python.org > > <mailto:python-ideas@python.org>> wrote: > > > > On 19/10/2023 19.50, Dom Grigonis wrote: > >> Thank you, > >> Good information, thank you. Was not aware of __set_name__. > > > > IIRC that was one of the updates/improvements. Thanks to whomsoever...! > > > > The: > > > > instance.__dict__[self.name <http://self.name/>] = value > > > > may require a bit of thought before it feels comfortable, but it is > > significantly easier to understand than what we had to do 'before'. > I am using `setattr(instance, self.name <http://self.name/>, value)`. But I > see that instance.__dict__ is more appropriate in this case. > > > > Another surprise, and I've assumed you're asking in the context of [Custom] > > Descriptors, is in how many places/functions Python makes use of a > > descriptor/descriptor protocol. Yet few of us seem to make use of them in > > our application code... > > (YMMV!) > I use them more and more. > > > However, I was more interested, why doesn't __set__ have an `owner` argument, > while `__get__` does. I am aware that this is not an issue at all as one can > simply do `inst.__class__`, but I am just curious about the reason for > inconsistency. > > Although, answers that I got were very useful. > > DG > _______________________________________________ > Python-ideas mailing list -- python-ideas@python.org > <mailto:python-ideas@python.org> > To unsubscribe send an email to python-ideas-le...@python.org > <mailto:python-ideas-le...@python.org> > https://mail.python.org/mailman3/lists/python-ideas.python.org/ > <https://mail.python.org/mailman3/lists/python-ideas.python.org/> > Message archived at > https://mail.python.org/archives/list/python-ideas@python.org/message/64MSMP4FFIT4FHPJQ66RW3OWXSP7RUFC/ > > <https://mail.python.org/archives/list/python-ideas@python.org/message/64MSMP4FFIT4FHPJQ66RW3OWXSP7RUFC/> > Code of Conduct: http://python.org/psf/codeofconduct/ > <http://python.org/psf/codeofconduct/> > > > -- > Antoine Rozo
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