Serialization of WeakReference<T> about messagepack-csharp

[pCYSl5EDgo]

How do you think this feature should be implemented?
Serialize may be implemented like T? but how do you implement Deserialize?
I do not know where to store deserialized object.

[AArnott]

It is a quite useful type for serialization of data that contain multiple instances of the same object,

I think you mean multiple references to the same object.
And msgpack doesn't support reference equality in its serializer, so even if we serialized such a type, you'd get each reference serialized as its own value, and upon deserialization, each "weak reference" object would be its own value, and as there would be no strong references to the object after deserialization, every copy would be GC'd, and you'd be left empty.

IMO you shouldn't be serializing weak references like this as it doesn't make sense when you think about the round trip.

[byte-arcane]

I think you mean multiple references to the same object.

Correct, sorry for the confusion.

msgpack doesn't support reference equality in its serializer
IMO you shouldn't be serializing weak references like this as it doesn't make sense when you think about the round trip.

Without thinking about limitations of the language/code, it's perfectly sensible: there's one resource owner and several references to it. I'm not sure how hard C#, or the design of this library makes this though. In C++ for example, shared_ptr and weak_ptr are normally supported in libraries such as cereal, so it's not a conceptual issue.

[AArnott]

So if the assumption is that someone in the object graph to be serialized has a strong reference to it, then yes, a deserialized copy could theoretically actually retain the object long enough to be noticed.

But it's all moot at the moment because messagepack doesn't de-duplicate objects during serialization. Every reference to an object gets serialized on its own. When and if #57 is ever addressed, that may allow something like weak reference support to make sense.