[vw7.7] Opentalk.OtWeakKeyDictionary bug?

Hi,

 

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