[IronPython] Possible bug in Ipy 2.6.1 WeakDictionary

Idan Zaltzberg idan at cloudshare.com
Mon Oct 4 18:02:13 CEST 2010


I'm investigating memory leakage in a Ipy 2.6.1 application.

Using WinDbg I found a WeakDictionary that is only increasing in size,
though most of the instances are already collected.

This WeakDicitionary is used by a DelegationInfo object.

Looking at the code, I think I found the problem:

The method CheckCleanup is called the method "public void Add(TKey key,
TValue value)"

*But it NOT called* from the indexer:

public TValue this[TKey key] {

            get {

                return dict[key];


            set {

                // If the WeakHash already holds this value as a key, it
will lead to a circular-reference and result

                // in the objects being kept alive forever. The caller needs
to ensure that this cannot happen.


                dict[new WeakObject(key)] = value;



Since the dictionary is populated using the indexer in DelegateInfo:

_constantMap[target] = new WeakReference(clone = (object

This means that the "version" field is never updated, and the dictionary
never gets cleaned up.

Have I got something wrong here?

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