Chainlink Local uses the EVM2AnyMessage `gasLimit` in tests for custom token pools

[ciaranightingale]

Expected Behaviour

The EVM2AnyMessage struct contains the field extraArgs in which you can pass _argsToBytes(EVMExtraArgsV1) in which EVMExtraArgsV1 has the member gasLimit. This custom gas limit is used for sending data with your cross chain message via the data member of EVM2AnyMessage. When sending a cross-chain message with no data data: "", the gasLimit can be set to zero.

Issue

In a fork test, the test fails due to an OutOfGas error. This same test passes if using the default gasLimit of 200_000. This implies that CLL is using the custom gas limit to execute the cross-chain transfer in the case of custom token pools.

Steps to Reproduce

Create a Foundry fork test that calls the following function to create and send a CCIP message:

function bridgeTokens(
        uint256 amountToBridge,
        uint256 localFork,
        uint256 remoteFork,
        Register.NetworkDetails memory localNetworkDetails,
        Register.NetworkDetails memory remoteNetworkDetails,
        RebaseToken localToken,
        RebaseToken remoteToken
    ) public {
        vm.selectFork(localFork);
        // struct EVM2AnyMessage {
        //     bytes receiver; // abi.encode(receiver address) for dest EVM chains
        //     bytes data; // Data payload
        //     EVMTokenAmount[] tokenAmounts; // Token transfers
        //     address feeToken; // Address of feeToken. address(0) means you will send msg.value.
        //     bytes extraArgs; // Populate this with _argsToBytes(EVMExtraArgsV2)
        // }
        Client.EVMTokenAmount[] memory tokenAmounts = new Client.EVMTokenAmount[](1);
        tokenAmounts[0] = Client.EVMTokenAmount({token: address(localToken), amount: amountToBridge});
        Client.EVM2AnyMessage memory message = Client.EVM2AnyMessage({
            receiver: abi.encode(user),
            data: "",
            tokenAmounts: tokenAmounts,
            feeToken: localNetworkDetails.linkAddress,
            extraArgs: ""
        });
        // extraArgs: Client._argsToBytes(Client.EVMExtraArgsV1({gasLimit: 0}))

        uint256 fee =
            IRouterClient(localNetworkDetails.routerAddress).getFee(remoteNetworkDetails.chainSelector, message);
        ccipLocalSimulatorFork.requestLinkFromFaucet(user, fee);
        vm.prank(user);
        IERC20(localNetworkDetails.linkAddress).approve(localNetworkDetails.routerAddress, fee);
        vm.prank(user);
        IERC20(address(localToken)).approve(localNetworkDetails.routerAddress, amountToBridge);
        uint256 localBalanceBefore = localToken.balanceOf(user);
        vm.prank(user);
        IRouterClient(localNetworkDetails.routerAddress).ccipSend(remoteNetworkDetails.chainSelector, message);
        uint256 localBalanceAfter = localToken.balanceOf(user);
        assertEq(localBalanceAfter, localBalanceBefore - amountToBridge);
        uint256 localUserInterestRate = localToken.getUserInterestRate(user);

        vm.selectFork(remoteFork);
        vm.warp(block.timestamp + 20 minutes);
        uint256 remoteBalanceBefore = remoteToken.balanceOf(user);
        ccipLocalSimulatorFork.switchChainAndRouteMessage(remoteFork);
        uint256 remoteBalanceAfter = remoteToken.balanceOf(user);
        assertEq(remoteBalanceAfter, remoteBalanceBefore + amountToBridge);
        assertEq(remoteToken.getUserInterestRate(user), localUserInterestRate);
    }

Outcome

The test fails unless using the default value for gasLimit