[Vm-dev] MessageTally broken in Cog

Eliot Miranda eliot.miranda at gmail.com
Sun Jul 4 18:00:37 UTC 2010


Hi Rob,

On Sun, Jul 4, 2010 at 10:12 AM, Rob Withers <reefedjib at yahoo.com> wrote:

>
> Eliot,
>
> I noticed that MessageTally was broken in Cog (which may or may not have
> anything to do with Coc).  It broke in MessageTally>>#spyEvery:on: inside
> the following code:
>
>        "Collect gc statistics"
>        SmalltalkImage current getVMParameters keysAndValuesDo: [ :idx
> :gcVal |
>                gcStats at: idx put: (gcVal - (gcStats at: idx))].
>
> gcVal was nil for index 4.  I looked at all the VMParameters and there are
> several nil values.  Is this a Cog thing?


Yes.  There are several vm parameters which are obsolete in Cog.  Answering
nil is IMO better than answering some fake value such as 0. Better to
provoke an error when fed with bad data than to hide the bug.

Should all VMParameters be non-nil?


IMO, no.


> Should MessageTally change to protect against nil values?
>

See [squeak-dev] The Trunk: System-ul.346.mcz


>
> Thanks,
> Rob
>
> ----
> The Modern Whig Party of Virginia - http://vawhigs.org
>
>
>
>
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