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Ok, I've found a fix for the second crash as well. My first fix is not perfect as assigning a new instance of the ConditionalWeakTable _weakExtends = new(); still keeps the referenced ExtendNotifier instances alive. They will eventually reach GC finalization and ask NoesisGUI to release itself (which 100% happens during the second reloading which always results in a crash; BTW, I've tried and it's NOT helpful to call GC.Collect() + GC.WaitForPendingFinalizers() to force collecting these references right after _weakExtends = new(); — some entries still remained in heap memory). Apparently I just need to ensure that no ExtendNotifier instances will ever invoke its finalizer if its parent _weakExtends is replaced with a new instance. Obviously it would be great if I can simply foreach references stored in _weakExtends and release each of them manually before creating a new instance of _weakExtends table. However ConditionalWeakTable doesn't support enumeration on .NET Framework (this is new API added in .NET Standard 2.1). The second idea was to store a WeakReference on the current _weakExtends... but apparently it's NOT supported — the WeakReference always replies NOT alive no matter whether _weakExtends is alive or not. (Ha-ha, so there is simply too much weakness for .NET to handle!) The third idea is simply to store the current version number of the _weakExtends instance: private static byte _latestWeakStorageId; So when I create a new _weakExtends instance in the ClearTables() method I simply increment the version number. I've put a simple check in ExtendNotifier finalizer:
if (currentWeakStorageId != _latestWeakStorageId)
{
// storage for this weak reference is destroyed, no need to release
return;
}
(of course, the field currentWeakStorageId in ExtendNotifier is assigned in its constructor) And it works! No more crashes. I think the only downside is that there are still some pointers (ExtendNotifier) stored in NoesisGUI native library which will be never released. (again, we cannot simply enumerate _weakExtends to release them all) But probably it's harmless and will not result in any major leak. Regards! |
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Thanks for the detailed info, I'm going to analyze it and see what would be the best option to fix this. |
- Anonymous
