YearnV3Strategy

Git Source

Inherits: BaseHealthCheck

Title: YearnV3Strategy

Author: Golem Foundation

Yield-donating strategy that compounds rewards from a Yearn v3 vault

Deposits assets into a Yearn v3 vault to earn yield, which is donated via BaseHealthCheck's profit minting mechanism YIELD FLOW:

1. Deposits assets into Yearn v3 vault
2. Vault generates yield from its strategies
3. On report, profit is minted as shares to donation address META-VAULT CONSIDERATION:

• If Yearn vault deposits into meta-vaults (e.g., Morpho → SteakHouse), maxDeposit may be inflated due to duplicate markets in supply queues
• This can cause temporary deposit DoS but doesn't affect withdrawals LOSS HANDLING:
• Accepts 100% loss on withdrawals to prevent revert cascades
• MultistrategyVault performs actual loss validation via updateDebt

Notes:

• security-contact: [email protected]

• security: Yearn vault convertToAssets must be manipulation-resistant

Quick Start - What Matters Most

Yearn V3 follows the .6 ERC-4626 safety pattern and uses Yearn's withdrawal maxLoss parameter internally. Review target vault liquidity and loss behavior before deployment.

State Variables

yearnVault

Address of the Yearn v3 vault this strategy deposits into

Must implement ITokenizedStrategy and use the same asset as this strategy

address public immutable yearnVault

Functions

constructor

Initializes the Yearn v3 strategy

Validates asset matches Yearn vault's asset. Approval is granted per-deposit in _deployFunds and explicitly cleared after the Yearn vault call.

constructor(
    address _yearnVault,
    address _asset,
    string memory _name,
    string memory _symbol,
    address _management,
    address _keeper,
    address _emergencyAdmin,
    address _donationAddress,
    bool _enableBurning,
    address _tokenizedStrategyAddress
)
    BaseHealthCheck(
        _asset,
        _name,
        _symbol,
        _management,
        _keeper,
        _emergencyAdmin,
        _donationAddress,
        _enableBurning,
        _tokenizedStrategyAddress
    );

Parameters

Name	Type	Description
_yearnVault	address	Address of the Yearn v3 vault this strategy deposits into
_asset	address	Address of the underlying asset (must match Yearn vault's asset)
_name	string	Strategy display name (e.g., "Octant Yearn USDC Strategy")
_symbol	string	Strategy symbol (e.g., "osYearnUSDC")
_management	address	Address with management permissions
_keeper	address	Address authorized to call report() and tend()
_emergencyAdmin	address	Address authorized for emergency shutdown
_donationAddress	address	Address receiving minted profit shares
_enableBurning	bool	True to enable loss protection via share burning
_tokenizedStrategyAddress	address	Address of TokenizedStrategy implementation contract

availableDepositLimit

Returns maximum additional assets that can be deposited

Queries Yearn vault's maxDeposit and subtracts idle balance META-VAULT WARNING: When Yearn vault points to meta-vaults (e.g., Morpho → SteakHouse), maxDeposit may be inflated if underlying vaults have duplicate markets. This can cause deposits to revert temporarily but doesn't indicate an issue.

function availableDepositLimit(
    address /*_owner*/
)
    public
    view
    override
    returns (uint256);

Returns

Name	Type	Description
<none>	uint256	limit Maximum additional deposit amount in asset base units

availableWithdrawLimit

Returns maximum assets withdrawable without expected loss

Sums idle balance and Yearn vault's maxWithdraw

function availableWithdrawLimit(
    address /*_owner*/
)
    public
    view
    override
    returns (uint256);

Returns

Name	Type	Description
<none>	uint256	limit Maximum withdrawal amount in asset base units

_deployFunds

Deposits idle assets into Yearn v3 vault

Note: security: Approves exactly _amount and clears the allowance after deposit, leaving no standing claim against the strategy's idle balance even if a target vault under-pulls.

function _deployFunds(uint256 _amount) internal override;

Parameters

Name	Type	Description
_amount	uint256	Amount of assets to deploy in asset base units

_freeFunds

Withdraws assets from Yearn v3 vault

Note: security: Target withdraw returns shares burned, not assets received. TokenizedStrategy._withdraw measures the post-call asset balance and applies the caller's max-loss limit. The Yearn call accepts 100% target-vault loss so the outer accounting can observe and enforce the realised result.

function _freeFunds(uint256 _amount) internal override;

Parameters

Name	Type	Description
_amount	uint256	Amount of assets to withdraw in asset base units

_emergencyWithdraw

Emergency withdrawal after strategy shutdown

Note: security: Delegates to _freeFunds, which calls the Yearn v3 vault with maxLoss = 10_000 BPS (100%). This preserves the shared emergencyWithdraw(uint256) ABI; emergency admins must assess acceptable Yearn loss off-chain before calling.

function _emergencyWithdraw(uint256 _amount) internal override;

Parameters

Name	Type	Description
_amount	uint256	Amount of assets to withdraw in asset base units

_harvestAndReport

Reports current total assets under management

function _harvestAndReport() internal view override returns (uint256 _totalAssets);

Returns

Name	Type	Description
_totalAssets	uint256	Sum of Yearn vault value and idle assets in asset base units