Hi Christoph,

> > I just wanted to suggest
> >                 ^ [(self vmParameterAt: parameterIndex)
> >                                                 ifNil: [defaultValueOrBlock value]]
> >                                 on: Error
> >                                 do: [defaultValueOrBlock value]
>  > 
> > i.e. without the return inside ifNil block…
>
> The only effective difference would be that if defaultValueOrBlock is a block and raises an error, it would be evaluated a second time. 
>
I still don't quite understand: if defaultValueOrBlock is a block and raises an error inside the ifNil block then the error would get handled by the above handler regardless whether there's a return inside the ifNil block or not - or not? :) The return should only evaluate after the exception resumes, I think. So actually it seems to me now the return should never get evaluated if defaultValueOrBlock raised an error (unless the error was resumable and resumed).  Or maybe I'm confused :) I'd like to be sure though I know how the evaluation goes in such cases, thanks!

> I cannot make sense of this behavior, can you? :-) Apart from that, the non-local return is a bit slower, I know, but IMHO this should only become an argument if there is no visible change in behavior.
>

Thanks for discussing this.

Best,


~~~
^[^    Jaromir

Sent from Squeak Inbox Talk

On 2021-12-16T20:02:34+00:00, christoph.thiede at student.hpi.uni-potsdam.de wrote:

> Hi Jaromir,
> 
> 
> > I just wanted to suggest
> >                 ^ [(self vmParameterAt: parameterIndex)
> >                                                 ifNil: [defaultValueOrBlock value]]
> >                                 on: Error
> >                                 do: [defaultValueOrBlock value]
>  >
> > i.e. without the return inside ifNil block…
> 
> 
> The only effective difference would be that if defaultValueOrBlock is a block and raises an error, it would be evaluated a second time. I cannot make sense of this behavior, can you? :-) Apart from that, the non-local return is a bit slower, I know, but IMHO this should only become an argument if there is no visible change in behavior.
> 
> 
> > So the default processPreemptionYields value remains false, right?
> 
> Apparently - without having studied the details of how preemption works in Squeak. :-)
> 
> Best,
> Christoph
> 
> ________________________________
> Von: Squeak-dev <squeak-dev-bounces at lists.squeakfoundation.org> im Auftrag von Jaromir Matas <mail at jaromir.net>
> Gesendet: Donnerstag, 16. Dezember 2021 20:47:27
> An: The general-purpose Squeak developers list
> Betreff: Re: [squeak-dev] Regression | Cannot interrupt "[ [] repeat ] fork" anymore
> 
> Hi Christoph,
> Yes, a good one 😊 I just wanted to suggest
>                 ^ [(self vmParameterAt: parameterIndex)
>                                                 ifNil: [defaultValueOrBlock value]]
>                                 on: Error
>                                 do: [defaultValueOrBlock value]
> 
> i.e. without the return inside ifNil block…
> 
> I noticed recently the image stopped responding to
> Smalltalk processPreemptionYields: false
> 
> So the default processPreemptionYields value remains false, right?
> Best,
> Jaromir
> 
> From: Thiede, Christoph<mailto:Christoph.Thiede at student.hpi.uni-potsdam.de>
> Sent: Thursday, December 16, 2021 20:29
> To: squeak-dev<mailto:squeak-dev at lists.squeakfoundation.org>
> Subject: Re: [squeak-dev] Regression | Cannot interrupt "[ [] repeat ] fork" anymore
> 
> 
> Ha, got it! This was a small regression in SmalltalkImage >> #processPreemptionYields from dtl 1/5/2021 19:29 (System-dtl.1261). Fixed in System-ct.1268. :-)
> 
> 
> 
> Best,
> 
> Christoph
> 
> Von: Thiede, Christoph
> Gesendet: Donnerstag, 16. Dezember 2021 19:29:30
> An: squeak-dev
> Betreff: AW: [squeak-dev] Regression | Cannot interrupt "[ [] repeat ] fork" anymore
> 
> 
> Hi Dave, hi Marcel,
> 
> 
> 
> one "recent" change I noticed is that one to SmalltalkImage>>#processPreemptionYields by Dave in May, which answered false before but answers true since then. But this is just an observation, I do not know whether this change was justified by a change on the VM side.
> 
> 
> 
> > even if CMD+Dot interrupts the "[ [] repeat ] fork" from the interrupt watcher
> 
> 
> 
> How did you achieve to do this? The interrupt doesn't work for me in this situation.
> 
> 
> 
> Best,
> 
> Christoph
> 
> 
> 
> Von: Squeak-dev <squeak-dev-bounces at lists.squeakfoundation.org> im Auftrag von Taeumel, Marcel
> Gesendet: Donnerstag, 16. Dezember 2021 15:53:37
> An: squeak-dev
> Betreff: Re: [squeak-dev] Regression | Cannot interrupt "[ [] repeat ] fork" anymore
> 
> Hi Christoph, hi Dave, hi all --
> 
> "Processor preemptedProcess" does not behave as it used to be. It now answers the current ui process even if CMD+Dot interrupts the "[ [] repeat ] fork" from the interrupt watcher.
> 
> Maybe you can spot the issue right away?
> 
> ProcessorScheduler >> preemptedProcess
> "Return the process that the currently active process just preempted."
> self activeProcess priority to: 1 by: -1 do: [:priority |
> (quiescentProcessLists at: priority) ifNotEmpty: [:list |
> ^ Smalltalk processPreemptionYields
> ifTrue: [list last]
> ifFalse: [list first]]].
> ^ nil
> 
> Best,
> Marcel
> 
> Am 16.12.2021 14:33:51 schrieb David T. Lewis <lewis at mail.msen.com>:
> On Thu, Dec 16, 2021 at 11:27:09AM +0100, Marcel Taeumel wrote:
> > Hi all --
> >
> > I am investigating a?? regression revealed via DebuggerTests >> test01UserInterrupt. One cannot interrupt "[ [] repeat ] fork" from a do-it anymore. :-(
> >
> > VM: 202112022203 (32-bit, Windows 10)
> >
> > Update: #20872
> >
> > Since the forked process should run at priority 40 and the "user interrupt watcher" watches at priority 60, this must work. Did we loose a process scheduling point in "[] repeat"? It's still implemented as "[self value. true] whileTrue".
> >
> 
> Confirming on Linux and also on an interpreter VM with trunk level V3 image,
> so the issue is in the image, not the VM.
> 
> Dave
> 
> 
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