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LidoDepositHook

Overview​

LidoDepositHook is an implementation of the IHook interface that acts as a conversion adapter for incoming deposits. It standardizes various ETH-like assets into wstETH for use in downstream vault logic. The hook supports ETH, WETH, and stETH as input formats and ensures conversion to wstETH before optionally forwarding execution to a downstream nextHook.

Primary Purpose​

  • Converts ETH, WETH, or stETH into wstETH on deposit.
  • Ensures compatibility with protocols that expect wstETH.
  • Provides composable hooks by chaining into a downstream IHook (nextHook).

Constructor Parameters​

ParameterTypeDescription
wsteth_addressAddress of the wstETH token contract
weth_addressAddress of the WETH token contract
nextHook_addressAddress of the optional downstream hook to forward to after wrapping

Key Function​

callHook(address asset, uint256 assets)​

Handles conversion of an input asset into wstETH and optionally delegates the call to a downstream hook.

Supported Input Types:

  1. wstETH: forwarded directly.
  2. stETH: wrapped into wstETH via IWSTETH(wsteth).wrap().
  3. WETH: unwrapped into ETH via IWETH(weth).withdraw(), then deposited into wstETH.
  4. ETH (that is address(0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE)): directly deposited into wstETH.

Execution Steps:

  • If asset == wstETH: do nothing.
  • If asset == stETH: approves wstETH to pull stETH and calls wrap() on wstETH to convert to wstETH.
  • If asset == WETH: unwraps to ETH using withdraw() and sends ETH to wstETH contract to mint wstETH.
  • If asset == ETH: sends ETH directly to wstETH.
  • After conversion, calculates how much new wstETH was received. If nextHook is configured, delegates callHook(wstETH, amount) to it.

Errors​

  • UnsupportedAsset(address asset) is thrown if the provided asset is neither wstETH, stETH, WETH, nor ETH.

Assumptions​

It is assumed this hook will not trigger STAKE_LIMIT or other limit related errors in the Lido contracts. If such errors do occur, the vault admin can reconfigure the system to bypass the automated staking hook. In this case, RedirectingDepositHook can be assigned to the relevant queues, delegating staking responsibilities to the vault curator via manual liquidity management.