[Zope] Will the inheritance relationship will be preserved af ter export/import?

[kosh@aesaeion.com]

Are you using zclasses or python products? I have not seen this behavior
with python products. If you are using zclasses then you should expect
this kind of thing. Zclasses are not robust solutions they mostly seem
designed for trivial solutions by largely non programmers.

On Thu, 10 May 2001, NABETH Thierry wrote:

> Hello Iap,
>
> >> The interitance relationship seems broken after export/import
> between different ZODB.
>
> Following is the message I have posted about this bug in January.
> I have mentioned already this bug several time, but until now I seemed
> to be the only one that care about this bug. (which makes me ask question
> about how much or how little the Zope community is using object orientation
> and inheritance with the Dtml language).
>
> I have personally stopped all design on the Zope platform (which I find
> some concept very interesting), and am concentrating my effort on
> Java/servlets
> because of this bug.
>
> I hope you find some way to solve your problems.
>
> Bye,
>
> Thierry
>
> -----Original Message-----
> From: Thierry Nabeth [mailto:Thierry.Nabeth@insead.fr]
> Sent: Saturday, January 06, 2001 10:46 PM
> To: zope@zope.org
> Cc: Thierry Nabeth
> Subject: Serious BUG in Export. ==> pb of lost inheritance if export /
> reimport.
>
>
> Hello,
>
> I would like to mention a very serious bug (for me), that prevent to use
> inheritance between two classes defined in two different package, if
> you have to export and reimport those packages.
>
> In a previous mail I mentionned a problem of Inheritance lost between
> packages.
>
> I spent a lot of time investigating the problem, and in particular looking
> in the
> export file (xml version).
>
> First here is the test:
>
> Phase 1: create the products and the classes.
>
> Create a product PA
> Create a class A in the product PA.
> Create a method "test" in class A.  (this method display "before").
>
> Create a product PB
> Create a class B in the product PB which inherits from A.
>
> Create an instance a of A.
> Create an instance b of B.
>
> Phase 2: test the inheritance.  ==> everything works fine
>
> Executing the method "test" on those two instances return.
> a.test  ==> "before"
> b.test  ==> "before"
> The result is correct.
>
> Phase 3: export / reimport product PB, and modify methode "test".
>
> Export the product PB. (PB.zexp is generated)
> Delete the product PB and restart zope.
> Import the product PB (PB.zexp) and restart zope.
>
> Modify the method "test" in class A..  (this method display "after").
>
> Phase 4: test the inheritance.  ==> B does not work correctly.
>
> Executing the method "test" on those two instances return.
> a.test  ==> "after"
> b.test  ==> "before"      ####### this is incorect. !!!!!!
>
>
> I spent a lot of time investing this problem, in particular looking
> in the xml export file.
> The problem is that when you export PB, the exported file also
> contain the definition of class A.
> When you re-import PB, B inherits from a class A that is different
> from the class A that is in the product PA.
> You have a kind of Zombie class A.
> (note: reimporting class A doesn't solve the problem).
>
> If someone has some idea how to fix this bug which almost forbid
> the use of inheritance between products in zope (unless you have a
> master server that never import anything) ?!
>
> Thierry Nabeth
> Research Fellow,
> INSEAD CALT (The Centre for Advanced Learning Technologies)
> http://www.insead.edu/CALT/
> Thierry.Nabeth@insead.fr
>
>
>