[ZODB-Dev] Re: [Zope-dev] Zope 2.5.0b4 problems w/ ZEO

[Chris McDonough]

> in this particular case, ZEO is a red herring...  In beta 4 (and
> curiously, not on the HEAD--I'm sure I'll hear a "mea maxima culpa" soon >
from someone) the base class for the SessionDataManagerTraverser was
> made to be a persistent object.  Since the base class changed, the ZODB
> is now having fits trying to reconcile the change in base classes.

Ugg.

> Since the session data manager object gets created automatically by Zope >
when it doesn't exist at system startup, you can make a new one (which
> inherits from Persistent) by:

<snip>

This all sounds right.  Thanks Matt!

Unfortunately, I don't think I can really make it so the transition between
2.4 <-> 2.5 (forwards and backwards) is completely seamless in all cases....
all I can do is provide software that helps folks get over their partiuclar
hump.  I think what might be in order is:

- A monkey patch to 2.3 and 2.4 that causes the request to ignore the
effects of a bad __before_publishing_traverse__ entry.  This will be the
prescription for "AttributeError: __call__" errors when downgrading from 2.5
to 2.3/2.4.  (Alternately, I could code up a little script that deleted the
root __before_publising_traverse__ method, but that would also rid the site
of access rules at the root).

- Prominent mention of Matt's workaround for upgrading from 2.5.0 beta 1-3
to 2.5.0 beta 4.