Unified proposals using v3.

[mcdee]

With the advent of the v3 blocks endpoint, it is possible to retrieve either a proposal or blinded proposal from the same endpoint. Unify the underlying data structure into a single proposal, and support the v3 endpoint.

Also move to using new-style options for the related Submit* calls.

[pinebit]

Is there an ETA for this to be merged and a new version to be released? Thanks!

[mcdee]

Is there an ETA for this to be merged and a new version to be released? Thanks!

There's an outstanding issue with one beacon node that I'd like to resolve prior to merging this (status-im/nimbus-eth2#5850), and I wouldn't release until after the Deneb hard fork as pre-Deneb consensus nodes won't necessarily have support for this endpoint.

[pinebit]

@mcdee I tried to estimate the integration effort for us and quickly identified one significant issue: the breaking change and one-way migration to v3 endpoint. In Charon we'd like to maintain backward compatibility for the transitioning period by putting v3 endpoint feature under a feature flag. This way our clients should be able to enable/disable this as they need. I do understand however that eventually all the components and projects will migrate to v3 endpoint.

Would it be possible to consider some "backward compatibility"? I suspect this would require to introduce another type like GenericProposal to not clash with the existing Proposal. And, given the purpose of this library is to define a model and serve as a library rather than a framework, you will give greater flexibility to all users.

[mcdee]

@pinebit supporting backward-compatibility can become very painful, and is not something that I'm comfortable with being able to provide.

My plan is to wait for all major clients (lighthouse,prysm,nimbus,teku) to support this endpoint to a given degree and then provide a release that uses this endpoint by preference. Users of this repo can stick with the current release (0.19.10) until they are ready to upgrade their own codebases to use the v3 endpoint.