blocks, ifCurtailed: and a crash... bug?

I added a method called #doWithProgress:caption: to Collection because I
noticed iterating over a collection with a progress display seemed to be a
common task.  I am using #ifCurtailed: to close the ProgessDialog if there
is an error or when there is a return out of the block.  I have done this
kind of thing before with ProgessDialogs, and it has always worked.  However
in my new method if there is a return in the block it does not return
properly and then causes a Dolphin VM crash.  It is reproducible.

This is an example of code that works:
(1 to: 10000) doWithProgress: [:each | each + 1] caption: 'test'.

This is an example of code that causes a crash:
(1 to: 10000) doWithProgress: [:each | each + 1. each >1000 ifTrue: [^nil]]
caption: 'test'.

I have tried placing the #ifCurtailed: message in different places, but it
still crashes.  Any thoughts?  Is this a bug in Dolphin, or my code?

The code for the doWithProgress: method is bellow:
==========================
!Collection methodsFor!

doWithProgress: oneOrTwoArgumentBlock caption: caption

 "cdemers - 2/1/2002 Perform a do over self while displaying and updating a
ProgressDialog.
  If oneOrTwoArgumentBlock has two arguments the progressDialog is passed as
  the second argument.  This allows the block to optionally update the text
as it
  runs."

 | progressDialog total count |

 progressDialog := ProgressDialog operation: [ :progress |
  total := self size.
  count := 1.
  self do: [:each |
   oneOrTwoArgumentBlock argumentCount = 1
     ifTrue: [oneOrTwoArgumentBlock value: each]
     ifFalse: [oneOrTwoArgumentBlock value: each value: progressDialog].
   count := count + 1.
   progress value: (count / total) * 100]].

 [progressDialog caption: caption;
  allowCancel: false;
  showModal]
 ifCurtailed: [progressDialog exit]! !
!Collection categoriesFor: #doWithProgress:caption:!*-unclassified!public! !
==========================

Chris

"Christopher J. Demers" <[hidden email]> wrote in
message news:a3f9j6$17tjpp$[hidden email]...
> I added a method called #doWithProgress:caption: to Collection because I
> noticed iterating over a collection with a progress display seemed to be a
> common task.  I am using #ifCurtailed: to close the ProgessDialog if there
> is an error or when there is a return out of the block.  I have done this
> kind of thing before with ProgessDialogs, and it has always worked.
However
> in my new method if there is a return in the block it does not return
> properly and then causes a Dolphin VM crash.  It is reproducible.
>...[snip]
> This is an example of code that causes a crash:
> (1 to: 10000) doWithProgress: [:each | each + 1. each >1000 ifTrue:
[^nil]]
> caption: 'test'.

I haven't had time to look at this in detail yet, but I suspect this is
crashing because the progress dialog forks off the block and runs it in a
different process. The VM should not be crashing, but nevertheless it is an
error to attempt to do a ^-return across processes.

Regards

Blair

Blair McGlashan <[hidden email]> wrote in message
news:a3jvlt$18q2cg$[hidden email]...
> I haven't had time to look at this in detail yet, but I suspect this is
> crashing because the progress dialog forks off the block and runs it in a
> different process. The VM should not be crashing, but nevertheless it is
an
> error to attempt to do a ^-return across processes.

Good point, I see what you mean.  I got around this by terminating the
process instead of returning, and restructuring my code a little.

FYI:  I noticed that ProgressDialog<<forkOperation has a minor typo in some
example code in the method comment:
'Processor activeProces priority: X' should be 'Processor activeProcess
priority: X'

Thanks,

Chris