Hi David,

I don't think is an issue of warning, even if I apply your patch I have the same error, see: https://imgur.com/a/pYcLLWx

To reproduce the bug:

Be on Big Sur 11.6.3 (20G415) https://support.apple.com/en-us/HT213055

Download Pharo 8: curl https://get.pharo.org/64/80+vm|bash

Open the image and evaluate ina playground:

Metacello new

configuration: 'OSProcess';

repository: 'http://www.squeaksource.com/MetacelloRepository';

load .

and then

(PipeableOSProcess command: 'ps') output.

The bug will show itself

Cheers

Davide

On Friday, February 4, 2022, 04:39:28 PM GMT+1, David T. Lewis <lewis@mail.msen.com> wrote:

Hi Davide,

Actually the warning has been removed in newer versions of OSProcess.
I do not have time to do an update for Pharo now, but in the mean time
you can apply this change in your image to remove the notifier:

AioEventHandler>>initializeForExceptions: exceptionEventFlag readEvents: readEventFlag writeEvents: writeEventFlag
    semaphore := Semaphore new.
    semaIndex := Smalltalk registerExternalObject: semaphore.
    (AioPluginPresent = true) ifTrue: [
        ([self aioEnable: self descriptor forSemaphore: self semaIndex externalObject: true]
            on: Warning
            do: [:e |
                self close. "unregister the semaphore"
                OSProcess trace: e messageText asString. nil])
            ifNotNil:
                [handlerProc := self
                    handleExceptions: exceptionEventFlag
                    readEvents: readEventFlag
                    writeEvents: writeEventFlag]]

HTH,
Dave

On Fri, Feb 04, 2022 at 03:05:57PM +0000, Davide Varvello wrote:
> Hi David,That's weird because if the AioPlugin is not present in my VM,??PipeableOSProcess shouldn't have worked till this morning... when I upgraded my mac :-)
> The warning is not skippable, it stops me at:??MessageNotUnderstood: IRJump>> #nextBytecodeOffsetAfterJumpCheersDavide
>
> On Friday, February 4, 2022, 03:54:59 PM GMT+1, David T. Lewis <lewis@mail.msen.com> wrote:
>
> On Fri, Feb 04, 2022 at 01:46:46PM +0000, Davide Varvello via Pharo-users wrote:
> > Hi guys,
> > Suddenly evaluating a simple: (PipeableOSProcess command: 'ps') output, or any other PipeableOSProcess command, Pharo gives me: "aio event forwarding not supported".
> > I guess it is something related to the latest update of the OS, specifically Big Sur 11.6.3 (20G415) https://support.apple.com/en-us/HT213055I'm on a Mac, of course, Pharo 8.0.0, Build information: Pharo-8.0.0+build.1128.sha.9f6475d88dda7d83acdeeda794df35d304cf620d (64 Bit)
> > Can you help me, please?CheersDavide
>
> Hi Davide,
>
> The warning message indicates that the AioPlugin is not present
> in your VM. I do not know the reason for that, although your
> PipeableOSProcess should still work if you proceed through the
> warning.
>
> Dave
>
>