Skip ERC20 allowance check and transfer when depositFor l1Amount is zero - Githubissues

thehubbleproject / hubble-contracts

Hubble optimistic rollup

https://thehubbleproject.github.io/docs/

MIT License

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Skip ERC20 allowance check and transfer when depositFor l1Amount is zero #627

Closed jacque006 closed 3 years ago

jacque006 commented 3 years ago

Problem

When a user calls DepositManager.depositFor with a zero (0) l1Amount, a ERC20 check and then transfer are called (https://github.com/thehubbleproject/hubble-contracts/blob/master/contracts/DepositManager.sol#L155-L159). This is unnecessary and leads to a higher gas cost.

Solution

Skip https://github.com/thehubbleproject/hubble-contracts/blob/master/contracts/DepositManager.sol#L155-L159 when l1Amount is 0.
Add test case for the above to https://github.com/thehubbleproject/hubble-contracts/blob/master/test/fast/deposit.test.ts , as well as test cases for require failures in depositFor.