On Mon, Oct 25, 2010 at 11:14:21PM +0100, David Glick wrote: > On 10/25/10 11:07 PM, Jim Fulton wrote: > > On Mon, Oct 25, 2010 at 5:58 PM, David Glick <davidgl...@groundwire.org> > > wrote: > >> On 10/25/10 10:51 PM, Jim Fulton wrote: > >>> I'm inclined to treat the use of the comparison operator inherited > >>> from object in BTrees to be a bug. I plan to fix this on the > >>> trunk. > >>> > >>> I'm tempted to fix this in 10.1. This change would make it impossible > >>> to add keys to BTrees or buckets or to add items to BTree-based > >>> sets if the key or items inherits it's comparison from object. This > >>> would only apply to instances of new-style classes, including > >>> persistent objects. (It wouldn't affect old-style-class instances, > >>> which are too hard to introspect.) > >>> > >>> Thoughts?
I like this. > >> The motivation here is that the comparison inherited from object > >> compares the objects' memory locations, which is not stable beyond > >> deactivation for persistent objects, and therefore not suitable for use > >> as a BTree key. Correct? > > Yup. Thanks for clarifying. > > > >> Preventing people from making that mistake > >> sounds like a good thing to me. > > It will likely reveal that current applications are broken. > > This will likely cause some pain. Where previously, > > apps simply lost data, now they'll error. I'm afraid that > > this might be too disruptive for a bug-fix release. > Maybe add it as an option defaulted to off? So that app developers who > want to check whether they have this problem can easily do so, and have > the extra protection once they've fixed any issues? Or perhaps make it emit DeprecationWarnings, but continue working. Then make it a fatal error in the next minor/major release. Marius Gedminas -- Include me out.
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