[vw7.7] Opentalk.OtWeakKeyDictionary bug?

> Since using VW7.7, we sometimes encounter an endless loop in OtWeakKeyDictionary.
>
> This is what the stack looks like:
>
> ...
> Opentalk.OtWeakKeyDictionary>>findKeyOrNil:
> Opentalk.OtWeakKeyDictionary>>findKeyOrNil:
> Opentalk.OtWeakKeyDictionary>>findKeyOrNil:
> Opentalk.OtWeakKeyDictionary>>findKeyOrNil:
> Opentalk.OtWeakKeyDictionary>>findKeyOrNil:
> Opentalk.OtWeakKeyDictionary>>findKeyOrNil:
> Opentalk.OtWeakKeyDictionary>>findKeyOrNil:
> optimized [] in Opentalk.OtWeakKeyDictionary>>at:ifAbsent:
> BlockClosure>>ensure:
> optimized [] in RecursionLock>>critical:
> BlockClosure>>ensure:
> Semaphore>>critical:
> RecursionLock>>critical:
> Opentalk.OtWeakKeyDictionary>>at:ifAbsent:
> optimized [] in Opentalk.ObjectTable>>export:for:
> BlockClosure>>ensure:
> optimized [] in RecursionLock>>critical:
> BlockClosure>>ensure:
> Semaphore>>critical:
> RecursionLock>>critical:
> Opentalk.ObjectTable>>export:for:
> Opentalk.ConnectionAdaptor(Opentalk.BasicObjectAdaptor)>>export:
> Opentalk.TCPTransport(Opentalk.Transport)>>export:
> Opentalk.TCPTransport(Opentalk.RequestTransport)>>export:
> Opentalk.STSTStream>>marshalObjectAsObjRef:
> Opentalk.STSTStream>>marshalPassByReferenceObject:
> Opentalk.STSTStream>>marshalObjectRecursively:
> Opentalk.STSTStream>>nextPutSTSTReply:
> optimized [] in Opentalk.STSTStream class>>initializeSpecialTypeDispatchTable
> Opentalk.STSTStream>>marshalTaggedObject:with:
> Opentalk.STSTStream>>marshalObjectRecursively:
> optimized [] in Opentalk.STSTStream>>marshalObject:
> BlockClosure>>on:do:
> Opentalk.STSTStream>>marshalObject:
> Opentalk.STSTMarshaler>>marshalTransportPayloadOf:into:
> Opentalk.TCPTransport(Opentalk.RequestTransport)>>createTransportPackageFrom:
> optimized [] in Opentalk.RequestTransport>>sendPackage:
> BlockClosure>>ensure:
> optimized [] in RecursionLock>>critical:
> BlockClosure>>ensure:
> Semaphore>>critical:
> RecursionLock>>critical:
> Opentalk.TCPTransport(Opentalk.RequestTransport)>>sendPackage:
> Opentalk.STSTReply(Opentalk.RemoteReply)>>send:
> optimized [] in Opentalk.RemoteRequest>>sendReply:for:
> BlockClosure>>on:do:
> Opentalk.STSTRequest(Opentalk.RemoteRequest)>>sendReply:for:
> Opentalk.STSTRequest(Opentalk.RemoteRequest)>>evaluateFor:
> Opentalk.STSTRequest>>evaluateFor:
> optimized [] in Opentalk.RemoteMessage>>dispatchFor:
> BlockClosure>>on:do:
> Opentalk.STSTRequest(Opentalk.RemoteMessage)>>dispatchFor:
> optimized [] in Opentalk.RemoteRequest>>dispatchFor:
> BlockClosure>>on:do:
> optimized [] in Process class>>forBlock:priority:
>
>
> We cannot reproduce it on demand, but here is some information I can provide for one case where it ran into the endless loop:
>
> The capacity of the dictionary is 101.
> The tally of the dictionary is 40.
> The slots in the #keys array are all /NOT NIL/.
> the #shrinkBound is 0.1  (this is a default value)
>
> When the #findKeyOrNil: method gets invoked, it tries to look for an empty slot, but even though there is enough room left (tally <  capacity), it doesn't find an empty spot because all slots in the #keys array are filled in with non-NIL values. Because no free slot is found, it tries to grow the dictionary but it doesn't grow it because the check in #grow:
>
> self tally / self capacity > self growBound
>
> returns false. Then it tries to do the findKeyOrNil: again and starts to loop until VW runs out of memory.
>
> I've noticed that the growing/shrinking behavior on OtWeakKeyDictionary has changed compared to vw7.4.1 & vw7.6. Perhaps this explains the loop?
>
> Is there a fix for this?
>
> Thanks,
> Mark

> Since using VW7.7, we sometimes encounter an endless loop in OtWeakKeyDictionary.
>
> This is what the stack looks like:
>
> ...
> Opentalk.OtWeakKeyDictionary>>findKeyOrNil:
> Opentalk.OtWeakKeyDictionary>>findKeyOrNil:
> Opentalk.OtWeakKeyDictionary>>findKeyOrNil:
> Opentalk.OtWeakKeyDictionary>>findKeyOrNil:
> Opentalk.OtWeakKeyDictionary>>findKeyOrNil:
> Opentalk.OtWeakKeyDictionary>>findKeyOrNil:
> Opentalk.OtWeakKeyDictionary>>findKeyOrNil:
> optimized [] in Opentalk.OtWeakKeyDictionary>>at:ifAbsent:
> BlockClosure>>ensure:
> optimized [] in RecursionLock>>critical:
> BlockClosure>>ensure:
> Semaphore>>critical:
> RecursionLock>>critical:
> Opentalk.OtWeakKeyDictionary>>at:ifAbsent:
> optimized [] in Opentalk.ObjectTable>>export:for:
> BlockClosure>>ensure:
> optimized [] in RecursionLock>>critical:
> BlockClosure>>ensure:
> Semaphore>>critical:
> RecursionLock>>critical:
> Opentalk.ObjectTable>>export:for:
> Opentalk.ConnectionAdaptor(Opentalk.BasicObjectAdaptor)>>export:
> Opentalk.TCPTransport(Opentalk.Transport)>>export:
> Opentalk.TCPTransport(Opentalk.RequestTransport)>>export:
> Opentalk.STSTStream>>marshalObjectAsObjRef:
> Opentalk.STSTStream>>marshalPassByReferenceObject:
> Opentalk.STSTStream>>marshalObjectRecursively:
> Opentalk.STSTStream>>nextPutSTSTReply:
> optimized [] in Opentalk.STSTStream class>>initializeSpecialTypeDispatchTable
> Opentalk.STSTStream>>marshalTaggedObject:with:
> Opentalk.STSTStream>>marshalObjectRecursively:
> optimized [] in Opentalk.STSTStream>>marshalObject:
> BlockClosure>>on:do:
> Opentalk.STSTStream>>marshalObject:
> Opentalk.STSTMarshaler>>marshalTransportPayloadOf:into:
> Opentalk.TCPTransport(Opentalk.RequestTransport)>>createTransportPackageFrom:
> optimized [] in Opentalk.RequestTransport>>sendPackage:
> BlockClosure>>ensure:
> optimized [] in RecursionLock>>critical:
> BlockClosure>>ensure:
> Semaphore>>critical:
> RecursionLock>>critical:
> Opentalk.TCPTransport(Opentalk.RequestTransport)>>sendPackage:
> Opentalk.STSTReply(Opentalk.RemoteReply)>>send:
> optimized [] in Opentalk.RemoteRequest>>sendReply:for:
> BlockClosure>>on:do:
> Opentalk.STSTRequest(Opentalk.RemoteRequest)>>sendReply:for:
> Opentalk.STSTRequest(Opentalk.RemoteRequest)>>evaluateFor:
> Opentalk.STSTRequest>>evaluateFor:
> optimized [] in Opentalk.RemoteMessage>>dispatchFor:
> BlockClosure>>on:do:
> Opentalk.STSTRequest(Opentalk.RemoteMessage)>>dispatchFor:
> optimized [] in Opentalk.RemoteRequest>>dispatchFor:
> BlockClosure>>on:do:
> optimized [] in Process class>>forBlock:priority:
>
>
> We cannot reproduce it on demand, but here is some information I can provide for one case where it ran into the endless loop:
>
> The capacity of the dictionary is 101.
> The tally of the dictionary is 40.
> The slots in the #keys array are all /NOT NIL/.
> the #shrinkBound is 0.1  (this is a default value)
>
> When the #findKeyOrNil: method gets invoked, it tries to look for an empty slot, but even though there is enough room left (tally <  capacity), it doesn't find an empty spot because all slots in the #keys array are filled in with non-NIL values. Because no free slot is found, it tries to grow the dictionary but it doesn't grow it because the check in #grow:
>
> self tally / self capacity > self growBound
>
> returns false. Then it tries to do the findKeyOrNil: again and starts to loop until VW runs out of memory.
>
> I've noticed that the growing/shrinking behavior on OtWeakKeyDictionary has changed compared to vw7.4.1 & vw7.6. Perhaps this explains the loop?
>
> Is there a fix for this?
>
> Thanks,
> Mark