Introduce cashu to host the shared types, traits and other common code

[crodas]

Description

Introduce a new crate, cdk-common, to host all the shared types and common functions and allow extensibility without having to include the cdk to avoid circular dependencies.

No major refactor has been done; only code has been moved to this new crate.

This will allow significant extensibility, making PRs like #509 and other similar initiatives much cleaner and easier to implement.

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Suggested CHANGELOG Updates

CHANGED

Introduced cdk-common, a new internal crate to host all shared types, traits, and common functions to extend the cdk without having to depend on it.

ADDED

REMOVED

FIXED

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Checklist

• I followed the code style guidelines
• I ran just final-check before committing

[thesimplekid]

Thanks for this PR, it makes sense to split this up.

Just left a few comments/questions.

More generally we have the option of naming cdk_common cashu and using the cashu name space on crates.io do you think that makes more sense then cdk_common? Just a naming thing really, but as what is called cdk_common in this PR is the basics of the cashu protocol I think it makes sense.

[crodas]

More generally we have the option of naming cdk_common cashu and using the cashu name space on crates.io do you think that makes more sense then cdk_common? Just a naming thing really, but as what is called cdk_common in this PR is the basics of the cashu protocol I think it makes sense.

I'll rename it to cashu

[thesimplekid]

I can do this so just as a reminder to myself.

• Add cashu crate to ci.

[ok300]

do you think cashu makes more sense then cdk_common?

Isn't that misleading?

The name gives no hint that it's a commons package for the CDK. Also, nobody will be able to use it without the CDK, as the structs and utils in it are "glue" for the other logic implented in the CDK mint and wallet.

For example, the bdk crate contains the actual BDK SDK, so it can be used on its own.

IMO cdk_common is more appropriate, as its only meant for CDK to use internally.

[ok300]

Side note: I find it curious that the PR is extracting common code, i.e. moving code or removing duplicates, and yet the diff is +1,326 −743. I didn't review in detail, but I think I saw a bunch of new things like signatory.rs.

Maybe it makes sense to add the new things in a separate PR on top of this, and keep this exclusively about consolidating existing code into the commons crate? Would make reviews easier. What do you guys think?

[crodas]

@ok300 I need to rebase better, but all the signatory code is from #509

[crodas]

I'll remove the signatory bits now and I'll add the features flags /cc @thesimplekid

[crodas]

@thesimplekid this is ready for review now

[thesimplekid]

I've updates the ci to include the new crates and some structs behind feature flags that are only needed for one of the feature.

[thesimplekid]

do you think cashu makes more sense then cdk_common?

Isn't that misleading?

The name gives no hint that it's a commons package for the CDK. Also, nobody will be able to use it without the CDK, as the structs and utils in it are "glue" for the other logic implented in the CDK mint and wallet.

For example, the bdk crate contains the actual BDK SDK, so it can be used on its own.

IMO cdk_common is more appropriate, as its only meant for CDK to use internally.

I think splitting it into cash and cdk-common addresses this concern. The cashu crate can be used without cdk it is just the core structs and functions that are defined in the spec. Someone could us this if they do not want a full cdk wallet or mint and only want to implement part of the protocol. Having this crate small and only what is defined in the spec also makes it easier to make it nostd so that it could be used on embedded devices. Then cdk-common is the cdk specific stuff that is not defined in the protocol (db traits, ln trait etc) but is used across cdk crates.

I think this is similar to rust-bitcoin and bdk split, just in a mono repo.

[thesimplekid]

ACK 94a4c87