[ZPatterns] large ZPatterns bug with Zope 2.4

[Steve Alexander]

I'm storing DataSkins in a Rack.

I'm upgrading a Zope 2.3 application to use Zope 2.4 and Python 2.1

I'm using the latest CVS of ZPatterns.

I've recompiled all the PythonScripts and (for good measure) refreshed 
all the SkinScript. External method available on request. I recompiled 
DynPersist.


There's an incompatibility between ExtensionClasses in Zope 2.4 and what 
DataSkin's __of__ method expects.

Basically, a DataSkin's _v_parent attribute is never set, because the 
first time __of__ gets called, parent is an ImplicitAcquisitionWrapper 
rather than an ImplicitAcquirerWrapper, as it was in Zope 2.3.

Right now, I'm not exactly sure what all this means. I'm about to start 
looking at the changelog for ExtensionClasses to find out.

It may be as simple as caching the parent at a different point in 
Dataskin's __of__, but I really don't know.

The result at the moment is that you can't use computed attributes with 
Zope 2.4.

--
Steve Alexander