Serializing and deserializing GBoxed types is fairly complicated
currently. If a GObject implements JsonSerializable it is possible
for the class to intercept the JsonNode, parse it manually and
then set the value to the property.

This leaves a hole opened for:

  • manual (de)serialization of GBoxed types
  • (de)serialization of GBoxed properties in classes not
    implementing JsonSerializable

In order to serialize and deserialize a GBoxed JSON-GLib should
provide a mechanism similar to the GValue transformation functions:
when registering the boxed type the developer should also be able
to register a serialization and a deserialization functions pair
matching the tuple:

  (GBoxed type, JSON type)

The serialization function would be:

  JsonNode *(* JsonBoxedSerializeFunc) (gconstpointer boxed);

And, conversely, the deserialization function would be:

  gpointer (* JsonBoxedDeserializeFunc) (JsonNode *node);

Obviously, the whole machinery...