LockupTranched: a new Lockup contract with sharply delineated chunks

[PaulRBerg]

As discussed here: https://github.com/sablier-labs/company-discussions/discussions/19

Tasks:

• Build a PoC implementation
• Benchmark the PoC against LockupDynamic:
  • Compare the creation of Unlock in Steps streams, e.g. this
  • Compare withdrawals from standard streams with one segment, i.e., how much more gas efficient will the withdraw function in LockupTranched be
• Decide if LockupTranched is worth it
• Proceed with writing tests for it (using Bulloak)

Note: we will keep using the same terminology, i.e., streams and streamedAmountOf. Related: #708 (comment)

[andreivladbrg]

Just wanted to let you know that I've implemented the POC and did benchmarks (see README file). You can see the work here:
https://github.com/andreivladbrg/v2-tranched/

Now it is up to decide if it worth implementing here.

[PaulRBerg]

Awesome, thanks @andreivladbrg, will review later.

[PaulRBerg]

Kudos, @andreivladbrg, for the benchmark you have prepared here.

I think it is as clear as day that we should move forward with LockupTranched.

• For 1-year vesting, it saves (i) up to 300K gas at creation time and (ii) up to 20k gas per withdrawal
• For 2-year vesting, it saves (i) up to 600K gas at creation time and (ii) up to 25k gas per withdrawal
• For 4-year vesting, it saves (i) up to 1.2M gas at creation time and (ii) up to 36k gas per withdrawal

These gas optimizations are due to LT making it possible to have half as many segments as LD. But LT is more efficient even when the number of segments is equal.

@razgraf could you give us the green light?

[razgraf]

Sounds good!

[PaulRBerg]

Great, thanks.

@andreivladbrg, you can move forward with implementing LockupTranched properly. The contract should be added in V2 Core.

Note: we should first merge #798

[andreivladbrg]

@andreivladbrg, you can move forward with implementing LockupTranched properly. The contract should be added in V2 Core.

I will, but currently I am working on making a huge refactor for core, that it would be very beneficial as the Lockup contracts are increasing

https://github.com/andreivladbrg/refactor-core/

saying it now, it may take a while

[PaulRBerg]

That's fine but please create a discussion/ proposal prior to a PR

[andreivladbrg]

34fee6b