===============

zopache.copy

=============== Copies graphs of ZODB objects, customize how any an Interface class is handled.

It is not so easy to copy a part of the ZODB graph. For starters every object has a __parent__ pointer, so you are liable to get the whole graph. Then you have the problem that some objects in a tree may point to objects in another part of the tree. You do not want to copy those objects, just copy a link to those objects. And I do not know which of your objects do what, so you have to be able to adapt the copying functions for any object you create.

This is a fork of Zope.copy. Why did I have to fork it?

Check out line 81 in __init__.py

hook = interfaces.ICopyHook(objectToBeCopied,None)

The ICopyHook is looking up an adaptor for the ObjectToBeCopied. And the way the zope registries work, things adapt one class (interface) and there is a default argument. But Cromlech adapters are more advanced. If you look up an adaptor with two arguments, it adapts two things, what Zope calls a multi-adaptor. And so zope.copy did not work in Cromlech.

So in cromlech, I tried declaring it to be an adapter of (Interface,None) but that threw an error. So I had to fork zope.copy to relace the one line with:

hook = interfaces.ICopyHook(obj)

Zope.copy had another prolem. It did not have a default Adapter

defined, so you had to figure out how to do it yourself. But I had an old version, and that documetned how to do it. So I have added a default cromlech adapter, so it is easy to get started with this package. I have also included the ancient but still useful readme from an earlier version of zope.copy

The current Zope.copy documentation is hosted at https://zopecopy.readthedocs.io/en/latest Mostly it applies. /