Reference integrity in BinaryFormatter

Question

The existence of AsReference option in Protobuf-net and the word that BinaryFormatter is a "graph serializer" lead me to assume that BinaryFormatter does not maintain references and that it makes a copy of every object.

But I did some tests and found out that all references in a single BinaryFormatter Serialize() or Deserialize() call are maintained even for recursive referencing.

Can I confirm that BinaryFormatter does indeed maintain references? How is this different from Protobuf-net? Seems like I understand "graph serialization" incorrectly? What else should I look out for?

Thanks in advance.

Answer 1

tl;dr; version - BinaryFormatter always preserves references.

The fact that BinaryFormatter is a "graph serializer" is synonymous with "it preserves references", since that is required to accurately reproduce a graph. The alternative is a tree serializer (which is most of them; XmlSerializer, DataContractSerializer (without a particular option enabled), JavascriptSerializer and protobuf-net without AsReference are all tree-based). Tree serializers do not generally preserve references (unless they work some tricks, i.e. what DataContractSerializer does if you enable full-graph mode, or protobuf-net does with AsReference). Tree serializers (without voodoo enabled) tend to explode in a mess with a recursive model, which makes them easy to spot.