Gas Optimizations

[code423n4]

Roundabout way of calculating L2GraphToken address

In L2GraphTokenGateway at L156 and L236 the L2GraphToken address is calculated as calculateL2TokenAddress(l1GRT), but this always just returns address(graphToken()). Consider skipping the check performed in calculateL2TokenAddress by replacing calculateL2TokenAddress(l1GRT) with address(graphToken()) at L156 and L236.

No need for SafeMath for user protection

SafeMath is not needed here as it is only a check to protect the user against his own invalid inputs.

Comparing to constant bool

Replace e.g. foo == false with !foo.

callhookWhitelist[msg.sender] == true

Unused function

Consider removing the unused function Managed.graphTokenGateway().

Unnecessary address(0)-check

_pendingImplementation != address(0) && msg.sender == _pendingImplementation can be simplified to msg.sender == _pendingImplementation as msg.sender cannot be address(0).

pendingGovernor != address(0) && msg.sender == pendingGovernor can be simplified to msg.sender == pendingGovernor as msg.sender cannot address(0).

_escrow != address(0) && Address.isContract(_escrow) can be simplified to Address.isContract(_escrow) as address(0) cannot be a contract.

Don't allow invalid parameters with a unique valid value

outboundTransfer() and finalizeInboundTransfer(), in both L1GraphTokenGateway.sol and L2GraphTokenGateway.sol, have as first parameter _l1Token which is immediately checked for its only acceptable value. Instead of checking whether its value is correct, leave the parameter void and simply declare its value inside the function.

Cache variable in memory

Move Governed.sol#L60 to before L54 so you can use the cached oldPendingGovernor instead of pendingGovernor at L55. (Then also emit oldPendingGovernor instead of governor at L65.)

Avoid accessing a storage variable when a cheaper alternative is available

Replace pendingGovernor with _newGovernor at Governed.sol#L46.

Replace pendingGovernor with address(0) at Governed.sol#L66.

Replace _partialPaused with _toPause at Pausable.sol#L31 and L34.

Replace _paused with _toPause at Pausable.sol#L45 and L48.

Replace pauseGuardian with newPauseGuardian at Pausable.sol#L58

Replace gateway with _gw at L2GraphToken.sol#L62

< is cheaper than <=

https://github.com/code-423n4/2022-10-thegraph/blob/309a188f7215fa42c745b136357702400f91b4ff/contracts/l2/token/GraphTokenUpgradeable.sol#L95