PoolGauge.withdraw() can be optimized when _value equals zero

[code423n4]

Handle

pants

Vulnerability details

The function PoolGauge.withdraw() doesn't have to execute these lines of code when _value equals zero:

_balance: uint256 = self.balanceOf[msg.sender] - _value
_supply: uint256 = self.totalSupply - _value
self.balanceOf[msg.sender] = _balance
self.totalSupply = _supply

self._update_liquidity_limit(msg.sender, _balance, _supply)

assert ERC20(self.lp_token).transfer(msg.sender, _value)

Impact

There is no reason to execute these lines of code if _value equals zero because they won't affect the system. An identical optimization is already implemented in PoolGauge.deposit().

Tool Used

Manual code review.

Recommended Mitigation Steps

Execute these lines of code only if _value doesn't equal zero.