Re: Simultaneous destructors

Chris Jones wrote:
> Benjamin Smedberg wrote:
>> On 11/11/09 10:26 AM, Benjamin Smedberg wrote:
>>
>>> I slightly prefer the divergent-path approach rather than the discard
>>> approach, for one main reason: it means that we don't have to implement
>>> special handling for actors which have already been "destructed" but are
>>> still receiving messages.
>>>
>>> I don't think my opinion is strong enough to *insist* on the 
>>> divergent-path
>>> approach, though. If we do go with the discard-bad-messages approach, 
>>> I'd
>>> like a very solid approach torwards zombie actor IDs.
>>>
>>> In any case, I'm also concerned with getting a theoretically sound 
>>> approach
>>> implemented for plugin destructor races for 1.9.3.
>>
>> I discovered another edge-case that needs consideration: when you pass an
>> actor as a parameter, it must be in a state that does not race with 
>> destruction.
>>
> 
> (ii) the way we've been passing actors around so far, 
> Msg(fooActor), will result in a 100% false-positive rate because 
> |fooActor| syntax means "fooActor may be in any state."

That's actually not entirely true ... more specifically, it would result 
in a positive (error) any time an actor was passed from A-->B when a 
dtor might possibly go from B-->A.  I imagine the false positive rate in 
this situation would be high.

Cheers,
Chris