Can there be a decode_without_loss() function in the candid rust crate that throws an error if the decoded structure would lose data in the de-serialization? A decode function that does not support the backwards compatibility features of candid?
The use case is for serialization during upgrades, I want to make sure users of a library in the post_upgrade hook don’t accidentally de-serialize their data onto a struct that would lose data.
@chenyan thoughts?
Candid is designed for describing interface, and is not a great fit for stable memory upgrade. The opt rule you mentioned is one problem. The other problem is that it doesn’t support sharing. It’s possible that a graph structure can take exponential space in stable memory. Have you considered other serialization format?
Thanks, I have considered some but there are many. Do you know of a good serialization format that supports sharing and cannot lose data on the de-serialization?
I don’t have first hand experience, but I’ve heard people using protobuf, MessagePack, and RON. They are probably also more cycle efficient than Candid.
That helps to narrow it down. MessagePack looks cool.