On 18 July 2011 13:08, Pedro Ferreira <jose.pedro.ferre...@cern.ch> wrote: >> TreeSets are essentially BTrees with only keys. This means that the >> members of a TreeSet must have a stable ordering. I suspect that that >> c's class does not define the comparison methods (such as __lt__) >> which means under Python 2 it falls back to the default ordering based >> on object id (Python 3 will raise a TypeError instead, avoiding this >> problem.) With ZODB an object's Python id (the memory address of the >> object) will change whenever it is reloaded, i.e. across restarts, >> after invalidation or removal from the cache. > > Yes, I know that. But I have a __cmp__ function defined, based on an > object property that never changes. That should be enough, no?
I think it should, but are you absolutely certain it never changes? Does list(s) == sorted(list(s)) and does list(s) == list(OOTreeSet(s))? Laurence _______________________________________________ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
