On Mar 29, 2011, at 9:58 PM, Denis Kudriashov wrote:

Hello

I have many morphs saved in files by smartReferenceStream. I doing it in pharo1.1 image.
Now I want to load this objects to pharo1.2.
When I doing this I have exception about absent TextConstants stuff. My saved Morph containes textMorph.
I know pharo1.2 has textMorph refactored and TextConstants was removed.

How old object can be migrated to new stuff? Is some rules exists?

No, I don't think so... keeping the system compatibel at that level is *really* difficult... simple refactoring can be done

(e.g. etoys did that for years), but complex changes in the image will be nearly impossible if you require serializability compatibility

at that level. (especially when using image segment style low-level serialization).

Being compatible on that level was religion for Squeak (and it's even today). I personally don't think that what we have is

valuable enough to define compatibility on that level to be more impotant than being able to evolve the system.

The system as it is now is just not good enough to have any form of future with it, so trading "improve it" vs. "be backward compatible

on a binary level" is selection between having the past and having a future...

Marcus