Combine external calls into one can save gas

[code423n4]

Handle

WatchPug

Vulnerability details

https://github.com/code-423n4/2021-11-vader/blob/429970427b4dc65e37808d7116b9de27e395ce0c/contracts/governance/GovernorAlpha.sol#L437-L445

for (uint256 i = 0; i < length; i++) {
    _queueOrRevert(
        proposal.targets[i],
        proposal.values[i],
        proposal.signatures[i],
        proposal.calldatas[i],
        eta
    );
}

https://github.com/code-423n4/2021-11-vader/blob/429970427b4dc65e37808d7116b9de27e395ce0c/contracts/governance/GovernorAlpha.sol#L466-L474

for (uint256 i = 0; i < length; i++) {
    timelock.executeTransaction{value: proposal.values[i]}(
        proposal.targets[i],
        proposal.values[i],
        proposal.signatures[i],
        proposal.calldatas[i],
        proposal.eta
    );
}

https://github.com/code-423n4/2021-11-vader/blob/429970427b4dc65e37808d7116b9de27e395ce0c/contracts/governance/GovernorAlpha.sol#L619-L627

for (uint256 i = 0; i < length; i++) {
    timelock.cancelTransaction(
        proposal.targets[i],
        proposal.values[i],
        proposal.signatures[i],
        proposal.calldatas[i],
        proposal.eta
    );
}

External call to timelock will be called each time in these for loops. They can be combined into batch external call by creating timelock.***Batch(...) function and call that function instead.

[SamSteinGG]

Agreed but we don't want to change the timelock contract as this is forked from Comp and max actions are 10.