C++ - Deserialize on a "non-serialized" bonded<T> should copy

[bch29]

I understand that the below is fundamentally useless, but I see no reason why it shouldn't work. It's essentially a transcoding from an in-memory value to the same representation. I think it should be supported for consistency's sake. This bit me when trying to write a unit test for some code where I wanted to fake receiving a bond encoded object from a server.

MyStruct value;
bond::bonded<MyStruct> bonded(value);

MyStruct value2;
bonded.Deserialize(value2);

[chwarr]

If I remember correctly, we decided not to implement "cloning via Bond" so that it wasn't easy to fall into a performance trap using the serialization/deserialization APIs. The "escape hatch" is to explicitly serialize to a buffer and then create a bond::bonded instance over the buffer:

template <typename ValueType>
static bond::bonded<typename ValueType> SerializeToBonded(const typename ValueType& value)
{
    bond::OutputBuffer outputBuffer;
    bond::CompactBinaryWriter<bond::OutputBuffer> writer(outputBuffer);
    bond::Apply(bond::SerializeTo(writer), value);

    bond::InputBuffer inputBuffer(outputBuffer.GetBuffer());
    bond::CompactBinaryReader<bond::InputBuffer> reader(inputBuffer);
    return bond::bonded<ValueType>(reader, false /*isBaseType*/);
}

Writing unit tests is the only case that I can remember where the need for this API comes up. (I've run into this exact problem myself before, and I implemented the aforementioned serialization function.)

I'd be fine with a behavior change here if someone wanted to submit it. Unit tests would be needed.