Re: [henshin-dev] Technical details for Henshin model migration

[Riegerf@xxxxxxxxxxxxxxxxxxxxxxx]

Quoting Stefan Jurack <henshin.stj@xxxxxxxxx>:
> Moreover, we won't roll-out two editor for two henshin.ecore version.
> The standard editor for old henshin-file will be the standard sample
> reflective editor with all its drawbacks.

Users usually aren't concerned with internal model changes. With  
increasingly better graphical editors for transformation rules, the  
internal model has become less and less important for the user.
Correctness of the henshin file is not enforced before saving, so a  
'broken' henshin file can be saved. I guess this happens a lot during  
rule development.
What we're trying to do is to convert a henshin file from the old  
model to the new model. Obviously, this will only work if the henshin  
file we're trying to convert is not only correct, but also follows  
some of the new model's conventions. If the conversion fails for any  
reason, the user will be presented with an error and is now required  
to fix the file before attempting a conversion again. Normally, the  
user should now be able to open the henshin file in question, modify  
it and start a new conversion. However, since currently we don't plan  
to supply the old editor, the user will now have no editor support  
whatsoever; this means errors in 'old' henshin files will be hard to  
find, editing will be very complicated, slow and error-prone. For  
small rulesets, creating the rules anew will probably be faster than  
trying to find an error and fix it using the sample reflective editor.  
This should never happen! Users should be concerned with working with  
the system, not editing their previously editable files with an  
extremely basic and overly complicated editor.

Shipping two editors will alleviate the problem. We should at least  
support the users in model migration, so one option to distribute the  
old editor(s) would be putting them in an optional package for the  
user to download separately.

Felix