[ZODB-Dev] Cached object error while upgrading Plone

[Shane Hathaway]

On 11/21/2011 10:40 AM, Alexandru Plugaru wrote:
> 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.

That kind of thing happens when a class changes from non-persistent to 
persistent or vice-versa. This may be caused by add-ons. When I do a 
major Plone upgrade, I first disable all add-ons temporarily and that 
usually does the trick.

If that doesn't work, I suggest you get a list of all your add-ons and 
ask this question on a Plone list.

Shane