2010/8/23 Michael Foord <fuzzy...@voidspace.org.uk>: > On 23/08/2010 23:55, Benjamin Peterson wrote: >> >> 2010/8/23 Raymond Hettinger<raymond.hettin...@gmail.com>: >>> >>> On Aug 23, 2010, at 1:13 PM, Benjamin Peterson wrote: >>> >>>> 2010/8/23 Michael Foord<fuzzy...@voidspace.org.uk>: >>>>> >>>>> To me hasattr *looks* like a passive introspection function, and the >>>>> fact >>>>> that it can trigger arbitrary code execution is unfortunate - >>>>> especially >>>>> because a full workaround is pretty arcane. >> >> hasattr(x, "y") doesn't look any more passive to me the x.y. > > One says "does this object have attribute y" the other fetches attribute y. > I'm amazed they don't look different to you. Given Python's object model > there is no reason that the first *should* fetch the attribute to determine > that it is present, *except* for the dynamic attribute creation of > __getattr__ and __getattribute__.
Actually, I'd say given Python's object model, you have to have the attribute in hand to determine that it is present. > > For properties there is *no reason* why code should be executed merely in > order to discover if the attribute exists or not. Properties are allowed to raise AttributeError, so you technically have to execute it. -- Regards, Benjamin _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
