Uniswap v4 Hook - Rewardin liquidity providers for ERC20-tokens 🦄

The hook supports flexible reward settings

Created based on a template v4-template

Description

The hook is designed to reward liquidity providers with ERC20 tokens. The reward is calculated when they withdraw liquidity in full or in part.

When the LP provides liquidity, the hook records the amount and the current time. Later, when liquidity is withdrawn, the reward is calculated based on this data and the hook accesses the token contract, calling the mint and mintit functions of the token to the user's address, or to another address that the user can specify.

Key Features

• Setting an individual multiplier for each user
• Support for increasing liquidity and partial withdrawal of liquidity
• Ability to set a minimum threshold of accumulated liquidity, reaching which the user will be rewarded
• Ability to set the rate for calculating the reward. Moreover, the rate is saved in the user structure, so the user can be sure that the rate for him will not change
• The hook will notify about the problem when minting the reward token (if this happens) through the event - CantMintReward

Hook has tests in test folder.

Check Forge Installation

Ensure that you have correctly installed Foundry (Forge) Stable. You can update Foundry by running:

foundryup

v4-template appears to be incompatible with Foundry Nightly. See foundry announcements to revert back to the stable build

Set up

requires foundry

forge install
forge test

Local Development (Anvil)

Other than writing unit tests (recommended!), you can only deploy & test hooks on anvil

# start anvil, a local EVM chain
anvil

# in a new terminal
forge script script/Anvil.s.sol \
    --rpc-url http://localhost:8545 \
    --private-key 0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80 \
    --broadcast

See script/ for hook deployment, pool creation, liquidity provision, and swapping.

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Troubleshooting

Permission Denied

When installing dependencies with forge install, Github may throw a Permission Denied error

Typically caused by missing Github SSH keys, and can be resolved by following the steps here

Or adding the keys to your ssh-agent, if you have already uploaded SSH keys

Anvil fork test failures

Some versions of Foundry may limit contract code size to ~25kb, which could prevent local tests to fail. You can resolve this by setting the code-size-limit flag

anvil --code-size-limit 40000

Hook deployment failures

Hook deployment failures are caused by incorrect flags or incorrect salt mining

1. Verify the flags are in agreement:
   • getHookCalls() returns the correct flags
   • flags provided to HookMiner.find(...)
2. Verify salt mining is correct:
   • In forge test: the deployer for: new Hook{salt: salt}(...) and HookMiner.find(deployer, ...) are the same. This will be address(this). If using vm.prank, the deployer will be the pranking address
   • In forge script: the deployer must be the CREATE2 Proxy: 0x4e59b44847b379578588920cA78FbF26c0B4956C
     • If anvil does not have the CREATE2 deployer, your foundry may be out of date. You can update it with foundryup

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Additional resources:

Uniswap v4 docs

v4-periphery contains advanced hook implementations that serve as a great reference

v4-core

v4-by-example