Gas Optimizations

[code423n4]

gas optimization

Avoid extra call for revoking allowance

On contracts/gateway/BridgeEscrow.sol/#L36-L39 instead of decreasing allowance and check user allowance, you could just do a grt.approve(0)

diff --git a/contracts/gateway/BridgeEscrow.sol b/contracts/gateway/BridgeEscrow.sol
index 605f13a..81b7a7c 100644
--- a/contracts/gateway/BridgeEscrow.sol
+++ b/contracts/gateway/BridgeEscrow.sol
@@ -34,7 +34,6 @@ contract BridgeEscrow is GraphUpgradeable, Managed {
      * @param _spender Address of the spender that will be revoked
      */
     function revokeAll(address _spender) external onlyGovernor {
-        IGraphToken grt = graphToken();
-        grt.decreaseAllowance(_spender, grt.allowance(address(this), _spender));
+        graphToken().approve(_spender, 0);
     }
 }

Cache the keccak hash in a constant

On:

• https://github.com/code-423n4/2022-10-thegraph/blob/main/contracts/governance/Managed.sol#L114
• https://github.com/code-423n4/2022-10-thegraph/blob/main/contracts/governance/Managed.sol#L122
• https://github.com/code-423n4/2022-10-thegraph/blob/main/contracts/governance/Managed.sol#L130
• https://github.com/code-423n4/2022-10-thegraph/blob/main/contracts/governance/Managed.sol#L138
• https://github.com/code-423n4/2022-10-thegraph/blob/main/contracts/governance/Managed.sol#L146

• https://github.com/code-423n4/2022-10-thegraph/blob/main/contracts/governance/Managed.sol#L154

  You could use a constant with the precalculated keccak.

Unused SafeMath lib.

Remove safemathlib on; https://github.com/code-423n4/2022-10-thegraph/blob/main/contracts/l2/gateway/L2GraphTokenGateway.sol/#L24

And Safemath import https://github.com/code-423n4/2022-10-thegraph/blob/main/contracts/l2/gateway/L2GraphTokenGateway.sol/#L7

Use +1 instead of safe math (its a safe operation)

On contracts/l2/token/GraphTokenUpgradeable.sol/#L97 Its safe to do + 1 instead of .add(1), nonces[address] is an uint256. If you do so you could also remove the import fo the safemath libraries.

Avoid calling burnFrom or _mint if there is nothing to burn/mint

on https://github.com/code-423n4/2022-10-thegraph/blob/main/contracts/l2/token/L2GraphToken.sol/#L91 Before calling burnFrom check before that _amount > 0

Similar on https://github.com/code-423n4/2022-10-thegraph/blob/main/contracts/l2/token/L2GraphToken.sol/#L81 Before calling _mint check before that _amount > 0