I have something that seems related.

I have a do-it that works fine with alt-D but when I run
it with the mouse menu, my VM crashes.  Crash.dmp says:
---------------------------------------------------------
Wed May 17 20:54:42 2000

Current byte code: 96
Primitive index: 0
Stack dump follows:

32635208 [] in PVTest>getIntervalFromNodes:
---------------------------------------------------------
This is the first VM crash I've seen in a long time.
Where do I look next?

-david

> -----Original Message-----
> From: Nathanael Schärli [mailto:n.schaerli at gmx.net]
> Sent: Wednesday, May 17, 2000 8:40 PM
> To: squeak at cs.uiuc.edu
> Subject: [BUG?] Strange behavior of exceptions and ensure:
> 
> 
> Hi Squeakers
> 
> Yesterday, I noticed a very strange behavior of the Squeak exception
> mechanism.
> The following example illustrates this (The code is also in 
> the attached
> fileout).
> 
> Create the new class StrangeExample and add the following methods:
> 
> StrangeExample class>>methodA1
> 	Transcript cr.
> 	self methodB.
> 	Transcript show: 'Finished1 '.
> 
> StrangeExample class>>methodB
> 	[self error: 'ErrorMsg ']
> 		on: Error do: 
> 		[:ex | 
> 		Transcript show: 'ErrorHandling '.
> 		ex return: 5].
> 	Transcript show: 'Finished2 '.
> 
> 
> Now it's getting interesting. Open a workspace and type the code:
> 
> StrangeExample methodA
> 
> Now select this code and use the shortcut cmd-d for 'do it'.
> As expected the Transcript output is:
> 'ErrorHandling Finished2 Finished1'
> 
> Now select the code again and use the mouse to select 'do it' in the
> context menu. Surprisingly the output in the Transcript is now:
> 'ErrorHandling Finished2'
> (I got this result with a current 2.8a image. Surprisingly I got the
> correct result using a default 2.7 image. However, the second 
> part of the example
> (described below) shows a strange behavior using either of 
> these images and
> thus this seems not to be a simple update bug).
> 
> Why is the result different? After some debugging, I saw that 
> the problem
> is the method BlockContext>>ensure: resp.
> BlockContext>>valueUninterruptably. If 'do it' is called via 
> the mouse, the whole code is executed inside an
> ensure:, but when it is called via shortcut the code is 
> executed without a
> call of ensure:.
> 
> To verify this, I wrote the following method:
> 
> StrangeExample class>>methodA2
> 	Transcript cr.
> 	[self methodB]
> 		ensure: [Transcript show: 'Ensure1 '].
> 	Transcript show: 'Finished1 '
> 
> As expected, the output on the Transcript is 
> 'ErrorHandling Finished2', and this independent wheter I 
> started it via
> mouse or shortcut and also independent of the image version.
> 
> It seems to me that execution stops when an exception occurse 
> inside an
> ensure: resp. valueUninteruptably.
> 
> Although I'm (up to a certain extent) familiar with the 
> BlockContext and
> Exception implementations, it would take me some time to look 
> at it closely.
> Therefore my question to the community: Can you confirm this 
> behavior? Is
> it a bug? If yes, does anyone have a fix?
> 
> Thanks
> 
> Nathanael
> 
> -- 
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>   Nathanael Schaerli
>   Ruettenenstrasse 41
>   CH-4515 Oberdorf, Switzerland
>     Phone: +41 32 622 89 03
>     Fax:   +41 32 621 78 50
>     Email: n.schaerli at gmx.net
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>  
>