Move `lightning::ln::types::*` to `lightning-types`

[tnull]

Follow-up to #3234

IMO, it's confusing that we now have both lightning::ln::types::* and lightning-types.

E.g., ChannelId is currently still in lightning::ln::types, should we move it to lightning-types?

[TheBlueMatt]

I do kinda prefer we re-export somewhere, and given our current paths are lightning::ln::types I don't see much reason to jump to remove that, but we could definitely move it to lightning::types (maybe after deprecating first - does rust let us mark re-exports deprecated?)

[tnull]

Right, we can keep the re-export, although longer term I'd prefer a single one via lightning::types. Just stumbled across the inconsistency while upgrading lightning-liquidity, so might be good to move ChannelId and make sure we won't keep scattering type definitions over multiple places.

[TheBlueMatt]

So maybe we re-export it as lightning::types now and deprecate (if possible) the ln::types exports?

[tnull]

I don't think you can currently deprecate a re-export? rust-lang/rust#30827

But still, switching to lightning::types and possibly refactoring a good chunk of modules now would be a good idea?

[TheBlueMatt]

IMO we already have a good bit of API breakage in this release, it'd be kinda nice to put off yet more until the next one.

[tnull]

IMO we already have a good bit of API breakage in this release, it'd be kinda nice to put off yet more until the next one.

Right, I meant we can still keep the double-reexport even though we can't deprecate one of them? But yeah, also not too important to do it right away. IMO we should fix the inconsistency mentioned above before the release though.

[TheBlueMatt]

I don't see much reason to move ChannelId to lightning-types, and sadly doing so is pretty irritating cause it has several in-crate dependencies.

[TheBlueMatt]

#3253

[Kixunil]

Maybe worth moving some things to ln-types? ChannelId definitely sounds like one of them.

[TheBlueMatt]

Sadly ChannelId depends on things in lightning so I don't think that's super practical. I did take a look through ln-types and it doesn't look like there's really much there we could migrate to, sadly, for various reasons. We generally have our own versions of all those types already, anyway, and our design tends to differ for various reasons.

[Kixunil]

I don't see any such dependency - the type contains just [u8; 32]. If you are referring to some methods having lightning types in their signatures that is solvable using extension traits (though I understand if you don't want to use them) or moving those things too. Especially your version of OutPoint looks interesting. EntropySource has frankly too weird design to my taste though. (what's the Deref thing about? Why harm performance by forcing shared references even when not needed?)

Anyway, no pressure, just feel free to ping me any time you want the crate. :)

[TheBlueMatt]

Yea, I was mostly referring to not wanting to deal with extension traits, which make docs super confusing for people :/.

[TheBlueMatt]

Untagging from 0.0.124 post-#3253, but moving to 0.1 to resolve the deprecateds by removing the old re-exports.