Mantis - Squeak
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6499 Morphic minor always 05-22-07 20:53 09-20-07 10:01
Simon Guest  
new 3.9  
0006499: Morph>>changed should call super changed
Morph>>changed overrides Object>>changed, but does not invoke super changed. This breaks the function of dependents, since dependent objects do not get notified of changes.

This affects 3.8 and 3.9, and the attached changeset works for both.
 Morph-changed.2.cs [^] (353 bytes) 05-22-07 20:53

05-23-07 03:39   
This affects a lot of classes in the morph hierarchy which may have made assumptions about what #changed will or will not do in the context of Morph.

Which is to say it would require a lot of tests to prove this repair is a safe one.
Simon Guest   
09-20-07 10:01   
I've just seen from discussion on Squeak-UI that there are serious performance issues around dependents, to do with WeakKeyDictionaries. The class comment for class Model (exists to provide fast dependents handling) also suggests that there is a performance pitfall here.

So maybe this was originally changed for reasons of performance, and should not be changed back. Perhaps somewhere there's someone who knows ...