✨♻️🥢: add FeeVaultSplitter.sol and FeeVaultSplitter.t.sol, update Gasback.sol and Gasback.t.sol

[j6i]

Description

• ✨: add FeeVaultSplitter.sol, used to split incoming sequencer fees from the BaseFeeVault
• add FeeVaultSplitter.t.sol to test FeeVaultSplitter.sol
• ♻️: updates to Gasback.sol
• • update accrued calculation
• • remove minVaultBalance, accruedRecipient, setAccruedRecipient, withdrawAccruedToAccruedRecipient
• • add baseFeeVaultShareNumerator, setBaseFeeVaultShareNumerator, _expectedBaseFeeVaultShareNumerator
• • lower gasbackRatioNumerator
• add @openzeppelin-contracts-4.9.5/ dep
• 🥢: fix "accural" misspelling (accural -> accrual)

Checklist

Ensure you completed all of the steps below before submitting your pull request:

• Ran forge fmt?
• Ran forge snapshot?
• Ran forge test?

Pull requests with an incomplete checklist will be thrown out.

[Vectorized]

Replicating baseFeeVaultShareNumerator across two contracts feels unclean tho.

I’m imagining a Solidity function triggerBaseFeeVaultWithdraw(uint expectedSelfBalanceAfter) external onlySelf that calls withdraw() on the baseFeeBault.

• and reverts if the self.balance < expectedSelfBalanceAfter.
• and passes if the self.balance >= expectedSelfBalanceAfter .

This function would then be called in Gasback’s receive() when funds are needed via a pop(call(…, which will make the inner revert silently pass as long as enough gas is given.

Logic in Gasback feels correct. Not sure about logic in the splitter.

[j6i]

Replicating baseFeeVaultShareNumerator across two contracts feels unclean tho.

I’m imagining a Solidity function triggerBaseFeeVaultWithdraw(uint expectedSelfBalanceAfter) external onlySelf that calls withdraw() on the baseFeeBault.

• and reverts if the self.balance < expectedSelfBalanceAfter.
• and passes if the self.balance >= expectedSelfBalanceAfter .

This function would then be called in Gasback’s receive() when funds are needed via a pop(call(…, which will make the inner revert silently pass as long as enough gas is given.

Logic in Gasback feels correct. Not sure about logic in the splitter.

made some updates, lmk what you think