Serialization of BorderedMorph

Hello all,

Still examining the various side effects of loading my old code in a 6.1 
image...

I found something rather disturbing:

When a BorderedMorph is reading from a file (or from any ref stream), 
its own (and very recent) implementation of #readDataFrom:size: sends 
#borderColor: and #borderWidth: (that is intended for backward 
compatibility).

This may have tricky side effects though, because both #borderColor: and 
#borderWidth: trigger #changed, which may itself update the layout of 
the morph. Since this happens while the morph is being read, in a 
context where the overall structure it is part of is not in a consistent 
state.

More generally, we do not know beforehand what a specific implementation 
of #borderWidth: may do.

For example, in Connectors, one implementation iterates over submorphs. 
This breaks if the submorphs inst. var. is nil at that point, which is 
the bug I got. It made it impossible to load the muO documentation, 
which is made of very complex morphs.

So in my use case, the fix to provide backward compatibility actually 
broke it :)

I can work around this on my side, but I believe this is a quite 
dangerous pattern: a Morph should not be tweaked in potentially 
arbitrary ways while it is being instanciated from a ref stream.


Stef



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