[Zope] Upgrading Zclasses

[Rob Page]

> What happens if two different people create ZClasses with the 
> same IDs?
> 
> For example:
> Alice creates ZClass Foo.  It gets an ID of 2.
> Bob creates ZClass Bar.  It also gets an ID of 2.
> 
> Bob imports Foo.  Since its ID is already used, I assumes it 
> gets assigned a
> new one, lets say 3.
> 
> Alice changes Foo, and sends Bob the new Foo.  When Bob 
> overwrites the old
> Foo with the new, Zope has to know the Foo's id was changed 
> to 3 from 2. (I
> admit to adding the second rhyme on purpose).

:^)

If two people create ZClasses with the same ID the scenario you describe
will occur.  However, the default class id (in the basic tab) is a hash
(MD5?) of the hostname and time.  The odds of accidentally getting the
same class id (unless you change the computed default) are very small.

--Rob