Backwards compatibility for serializing empty collections

[zxpectre]

Hey @lisicky ! thanks for all the work you guys are putting for Chang HF. I'm updating GC using tag 12.0.0-beta.7 as time is running out.

Specifically wanted to ask about:

• CSL now doesn't serialize empty collections for most witness types, in accordance with CDDL.

Can you provide backwards compatibility with those classes keeping the old behavior maybe using a property flag or some other idea?

Apps and even libraries built on top of CSL may break, past flexibility of the library encouraged us to serialize structures beyond direct protocol usage, for example for exportable witness containers for multisig. By using CSL one avoids reinventing the wheel and dealing with similar CBOR manually, also this means less external dependencies.

In general terms regarding backwards compatibility, maybe classes (data) could remain flexible but methods consuming them could apply rules and restrictions internally?

Thanks for the hard work!

[lisicky]

Hi @zxpectre!
For some structures, we can provide a flag to force a specific serialization format if there is a reasonable use case. However, in the case of collections explicitly defined as non-empty in the CDDL, we cannot provide such a flag due to limitations in the Conway protocol.
If you have a specific use case that might be affected by the changes in the Conway protocol, please let me know.

[zxpectre]

Thanks @lisicky, will try to spot all the issues these days and will come up to you again if I get blocked by any. Still working on Chang readiness, was a big work load for us.
Is there another channel where wallet builders could get updated on time and maybe share early feedback on future changes?

[lisicky]

@zxpectre GitHub issues is the primary channel to have any discussion about CSL