[Zope] Pb. of Inheritance lost between packages. (after too many export/imports ?) export/imports ?)

[Thierry Nabeth]

Hello,

Here is this problem again that has reappeared  !!!!
I already posted about this problem some months ago,
but did not manage to make it work, and I had to rewrite
all the class from scratch.
(of course, I did a lot of cut and past, but you
have to do a lot of manual work recreating the
Properties, and you loose all the instance you had created).

Here is my problem: 

I have 3 Products PA PB PC
and I have the 3 classes A, B and C defined in each of the
different Products.

PA has class A
PB has class B
PC has class C.

Besides, the inheritence tree is the following:

A <-- B  <-- C.
(A inherits from B, etc.)

The problem is that after some time (after many export and re-import of
Products),
the inheritance does not work anymore between the package.

For instance if I define a new method in class A,
it is invisible from class B.
Or if I redefine a method in a Class A, the class B still 
see the old method of class B.

Note that at the beginning, when you create those three packages
and classes, everything seems to work fine.
(I have done the test).

Did someone already encountered a similar problems ?
Do someone has an idea what could be wrong, and has some idea about
how to fix the problem ? 
(my guess is that something wrong happens after too many
export and imports which confuses python).

Thierry Nabeth
Research Fellow,
INSEAD CALT (The Centre for Advanced Learning Technologies)
http://www.insead.edu/CALT/
Thierry.Nabeth@insead.fr