Yearn Starter Kit

Hardhat example: https://github.com/storming0x/ystarter-hardhat-kit

All code in this repository is meant for instructional purposes only. Is not audited or considered safe for production.

What you'll find here

• Basic example Solidity Smart Contracts for integrating with Yearn Vaults. Both V2 and ERC4626 interfaces.

• ERC4626 adapter to wrap yearn vaults.

• Example Contracts (examples)

• Sample test suite. (tests)

Yearn Vault -> ERC4626 Adapter

(contracts/VaultWrapper.sol)

VaultWrapper is an ERC4626 adapter interface that makes v2 vaults compatible with the standard. A wrapper is needed per deployed vault. Contracts can interact with the wrapper as they would with any ERC4626 since it adapts the standard completely.

NOTE: This adapter makes all V2 vault operations more gas expensive since its doing additional calls to normal vault methods like deposit/operations to wrap the vault tokens into the ERC4626 adapter.

Given the flexibility, the gas increase tradeoff may be good for integrators using multiple ERC4626 to keep code cohesive for all yield sources.

Also future proofs integrations since V3 vaults will be ERC4626 compatible on launch.

Contract Example that works with compatible ERC4626 tokens and Yearn V2 VaultsAPI

(contracts/examples/SugarVault.sol) (contracts/examples/SugarYvault.sol)

SugarVault is an example contract that works internally with any ERC4626 compatible yield token. SugarYvault has the same functionality but uses Yearn V2 interfaces.

Example functionality

• These contracts accepts donators underlying tokens and deposits it into yield source and configures a receiver.
• The receiver can claim as stream the yield generated by the donator deposits when available.
• The donator can stop yield sharing at any moment and retrieve the underlying token capital deposited plus any unclaimed yields from receiver.

Possible Features to hack

• Tokenized the contract as NFT for donations. Could use two linked NFTs by id, one for donator and one for receiver that can be transfered to claim each part of their funds.
• Add support for migrating yield sources to other ERC4626. Requires same underlying token.

Installation and Setup

1. To install with Foundry.

2. Fork this repository.

3. Clone your newly created repository recursively to include modules.

git clone --recursive https://github.com/storming0x/ystarter-foundry-kit.git

cd ystarter-foundry-kit

NOTE: if you create from template you may need to run the following command to fetch the git submodules (.gitmodules for exact releases) git submodule init && git submodule update

4. Build the project.

make build

5. Sign up for Infura and generate an API key and copy your RPC url. Store it in the ETH_RPC_URL environment variable. NOTE: you can use other services.

6. Use .env file

7. Make a copy of .env.example

8. Add the values for ETH_RPC_URL, ETHERSCAN_API_KEY and other example vars NOTE: If you set up a global environment variable, that will take precedence.

9. Run tests

make test

Basic Use

To deploy the demo Yearn Vaults and ERC4626 adapter in a development environment:

TODO

Testing

Tests run in fork environment, you need to complete Installation and Setup step 6 to be able to run these commands.

make test

Run tests with traces (very useful)

make trace

Run specific test contract (e.g. test/MyTest.t.sol)

make test-contract contract=MyTest

Run specific test contract with traces (e.g. test/MyTest.t.sol)

make trace-contract contract=MyTest

See here for some tips on testing Testing Tips

Resources

• Yearn Discord channel
• Getting help on Foundry
• Forge Standard Lib
• Awesome Foundry
• Foundry Book
• Learn Foundry Tutorial