On 6/8/07, Alek Kowalczyk <[EMAIL PROTECTED]> wrote:


Alek Kowalczyk <[EMAIL PROTECTED]> writes:

>
> Hi,
> I moved my content class from mypackage.mymodule.MyContentClass into
> mypackage.mysubpackage.mymodule.MyContentClass.
> But when started Zope and went to visit an object I have previously
created (of
> MyContentClass), I get:
> ComponentLookupError: ((<persistent broken
mypackage.mymodule.MyContentClass
> instance '\x00\x00\x00\x00\x00\x00\x02q'>,
> <zope.publisher.browser.BrowserRequest instance

I found a quite well working solution on
http://mail.zope.org/pipermail/zodb-dev/2006-September/010382.html

There was only one issue: this solution assumes that we have given a DB,
while
Zope evolve method receives already open connection. Unfortunately
classFactory
from DB is cached in Connection's private fields in constructor.
Because of that I could not assign my custom 'renaming' class factory
using:

def evolve(context): #won't work!
    context.connection.db().classFactory = myClassFactory

Instead I had to do some dirty private fields substitution in Connection's
ObjectReader:

def evolve(context): #this works nice
    context.connection._reader._factory = myClassFactory


I shouldn't announce success too early. The solution works but only during
first Zope run (i.e just after evolving the schema).
Although classFactory returns proper class during evolve, the new class name
is not saved in ZoDB, so after next unghosting object get old class names
again.

Here is my evolve script. I really don't know what more should I do to make
Zope/ZoDB write the new class name in ZoDB. Can someone help me a bit... :)
?

def convertingClassFactory(connection, moduleName, globalName):
   #convert class name to new one and return the class object

def evolve(context):
   #dirty hack to substitute classFactory
   context.connection._reader._factory = convertingClassFactory
   root = context.connection.root().get(ZopePublication.root_name, None)
   for object in findObjectsMatching(root, lambda x: True):
       if hasattr(object, '_p_activate'):
           object._p_activate()
           object._p_changed = True
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