[MC] Bug loading interesting class redefinitions

Avi Bryant avi at beta4.com
Tue Oct 14 21:31:08 UTC 2003


On Tuesday, October 14, 2003, at 11:48 AM, Daniel Vainsencher wrote:

> When I try to load
> http://modules.squeakfoundation.org/People/dvf/Packages/SMBase- 
> dvf.13.mc
> z into a more or less clean image 3.7 using MC, I get an error because
> of adding a variable to a class that exists in a superclass (IIUC). I'd
> guess what is happening is that the superclass gets redefined to not
> have the variable, but it comes later in the load order. This can be
> worked around by proceeding in the walkback. After that I loaded the
> file again, and things seemed ok.

Hm, that doesn't quite make sense - the superclass should always be  
loaded before the subclass.  I would expect this problem to happen when  
pushing ivars up from a subclass to a superclass, but not the other way  
around.

Either way, of course, it needs to be fixed.  I'm not sure exactly what  
the best approach is.  Incidentally, I've found in the past that  
changesets can exhibit a similar problem.

Perhaps MC should catch such exceptions, and defer those loads, trying  
them again at the end?  Does it throw a generic Error or is there a  
specific exception for it?



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