[ZODB-Dev] Cached object error while upgrading Plone

[Alexandru Plugaru]

Hello,

I've got this error ( http://pastie.org/2898828 ) while upgrading from
plone3 to plone4. The context in which that error happens is this:
http://pastie.org/2898959

The only place I could find the error message was in cPersistence.c:
http://svn.zope.org/*checkout*/ZODB/branches/3.9/src/persistent/cPersistence.c

So I guess my question is how do I know if an object is cached? And
maybe a theory of why this is happening.

Thank you,
Alex.