[Zope] Upgrading Zclasses

[Jim Fulton]

"Itamar S.-T." wrote:
> 
> Rob Page wrote:
> 
> > If you distribute a ZClass definition and then upgrade it it will still
> > have the same id.  As a result, when you overwrite the new ZClass
> > definition over the older one, it also will have the same class
> > definition.  Restarting Zope will cause the new ZClass definition to be
> > loaded and the instances get the new behavior...  Pretty cool...
> 
> 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.

Bob will get an error when he tries to import foo, and he will
complain to Alice for using such a silly ID. (Of course, he
won't mention to her what a silly ID he picked.)

As others have pointed out, the ids generated by ZClasses
have an extremely low chance of collision.

Jim

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