Deposits accounting

[Psirex]

Deposit accounting & contracts changes:

• StakingRouter now accepts the precise amount of deposits to make. If StakingRouter can't make the requested number of deposits, it will revert the transaction.

• StakingRouter doesn't return ETH to the Lido contract after the deposit, so the Lido.receiveStakingRouterDepositRemainder() method was removed.

• StakingRouter.getStakingModuleMaxDepositsCount() method signature changed. It now accepts two arguments: stakingModuleId and the max amount of ether that might be deposited.

• IStakingModule.obtainDepositData() now must return the exact number of requested keys. If StakingModule doesn't have enough deposit data items, it MUST revert

• IStakingModule.obtainDepositData() now doesn't return depositsCount as the first item. Only publicKeys and signatures returned now

• Assertion that deposited correct amount of ETH was moved from the BeaconChainDepositor contract to StakingRouter for clarity

• Lido._markAsUnbuffered() method was removed. Now, the buffered ether value is updated in place on deposit, like in other methods.

• Assert for unaccounted ether was removed from Lido. Previously such a check was relevant cause the deposits happened in the Lido contract itself. In the current implementation, ETH is sent to StakingRouter, where deposits happen, which contains assert that exactly the received amount of ETH was deposited.

• Lido._getUnaccountedEther() method was removed

• Lido.getDepositableEther() returns a value not multiple to 32 ether

• Check that stakingModuleId is less than type(uint24).max was removed from Lido.deposit() cause external interface of staking modules declares id as uint256

[TheDZhon]

It's awesome 😮

Good to know that it saves a bytecode size also: