"Don't make me think"...

goran at krampe.se goran at krampe.se
Tue Apr 18 19:37:39 UTC 2006


Hi!

Adrian Lienhard <adi at netstyle.ch> wrote:
> ... is a good usability guideline.
> 
> Now, this question (see attached screenshot) made me think a lot ;-).  
> And surprising enough, it even proposes "thinking" as one of the  
> answers (as if the developer knew upfront that the user is going to  
> have a hard time to guess right). I have no clue what the right  
> answer should be. Does anybody know what this is all about?

Yes, this is about how an image with the "wrong" classes should load an
ImageSegment.
The code asking the questions is not SM itself - it is
ImageSegment/SmartRefStream code getting into trouble.

Now, the issue is that if you have multiple images sharing the same "sm"
dir (which is fine in principle) and you update one of those images to
the current new SM 2.2 - then when the old images try to synch with disk
(which they do when you fire up the SMLoader) they end up trying to load
an ImageSegment produced by the SM master server running 3.8 into a 3.7
image - which is a NO GO as I mentioned earlier here:

	http://lists.squeakfoundation.org/pipermail/squeak-dev/2006-April/10228
6.html

Now, it would be dandy if I had thought about this scenario "yesterday"
and added code that can handle "new" ImageSegments and do something
"smart" - unfortunately I didn't have that foresight and I can't
magically "fix" all images already out there.
 
> Btw, using latest 3.9a image, and the default SM bugfixing technique  
> (*) solved this problem too.

Let me repeat:

1. For the above issue - press alt-. and then instead execute
"SMSqueakMap bootStrap" which will force an upgrade of SM in the image.
No need to nuke the sm dir.

2. Even if you feel tempted to delete the whole "sm" dir, it is
sufficient to delete the .sgz files. That way you don't needlessly throw
away the package cache. :)
 
> Cheers
> Adrian

regards, Göran



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