feat: Add ForgeArtifacts.getSlot() (ethereum-optimism#13787)

Author: maurelian

packages/contracts-bedrock/scripts/libraries/ForgeArtifacts.sol

@@ -152,8 +152,6 @@ library ForgeArtifacts {
 
     /// @notice Pulls the `_initialized` storage slot information from the Forge artifacts for a given contract.
     function getInitializedSlot(string memory _contractName) internal returns (StorageSlot memory slot_) {
-        string memory storageLayout = getStorageLayout(_contractName);
-
         // FaultDisputeGame and PermissionedDisputeGame use a different name for the initialized storage slot.
         string memory slotName = "_initialized";
         string memory slotType = "t_uint8";
@@ -162,6 +160,7 @@ library ForgeArtifacts {
             slotType = "t_bool";
         }
 
+        string memory storageLayout = getStorageLayout(_contractName);
         bytes memory rawSlot = vm.parseJson(
             Process.bash(
                 string.concat(
@@ -186,6 +185,31 @@ library ForgeArtifacts {
         });
     }
 
+    /// @notice Returns the storage slot for a given contract and slot name
+    function getSlot(
+        string memory _contractName,
+        string memory _slotName
+    )
+        internal
+        returns (StorageSlot memory slot_)
+    {
+        string memory storageLayout = getStorageLayout(_contractName);
+        bytes memory rawSlot = vm.parseJson(
+            Process.bash(
+                string.concat("echo '", storageLayout, "' | jq '.storage[] | select(.label == \"", _slotName, "\")'")
+            )
+        );
+        ForgeStorageSlot memory slot = abi.decode(rawSlot, (ForgeStorageSlot));
+        slot_ = StorageSlot({
+            astId: slot.astId,
+            _contract: slot._contract,
+            label: slot.label,
+            offset: slot.offset,
+            slot: vm.parseUint(slot.slot),
+            _type: slot._type
+        });
+    }
+
     /// @notice Returns whether or not a contract is initialized.
     ///         Needs the name to get the storage layout.
     function isInitialized(string memory _name, address _address) internal returns (bool initialized_) {

packages/contracts-bedrock/test/L1/L1CrossDomainMessenger.t.sol

@@ -11,6 +11,7 @@ import { AddressAliasHelper } from "src/vendor/AddressAliasHelper.sol";
 import { Predeploys } from "src/libraries/Predeploys.sol";
 import { Hashing } from "src/libraries/Hashing.sol";
 import { Encoding } from "src/libraries/Encoding.sol";
+import { ForgeArtifacts } from "scripts/libraries/ForgeArtifacts.sol";
 
 // Target contract dependencies
 import { IL1CrossDomainMessenger } from "interfaces/L1/IL1CrossDomainMessenger.sol";
@@ -22,7 +23,12 @@ contract L1CrossDomainMessenger_Test is CommonTest {
     address recipient = address(0xabbaacdc);
 
     /// @dev The storage slot of the l2Sender
-    uint256 constant senderSlotIndex = 50;
+    uint256 senderSlotIndex;
+
+    function setUp() public override {
+        super.setUp();
+        senderSlotIndex = ForgeArtifacts.getSlot("OptimismPortal2", "l2Sender").slot;
+    }
 
     /// @dev Tests that the implementation is initialized correctly.
     /// @notice Marked virtual to be overridden in

packages/contracts-bedrock/test/invariants/CrossDomainMessenger.t.sol

@@ -10,10 +10,11 @@ import { Predeploys } from "src/libraries/Predeploys.sol";
 import { Constants } from "src/libraries/Constants.sol";
 import { Encoding } from "src/libraries/Encoding.sol";
 import { Hashing } from "src/libraries/Hashing.sol";
+import { ForgeArtifacts } from "scripts/libraries/ForgeArtifacts.sol";
 
 contract RelayActor is StdUtils {
     // Storage slot of the l2Sender
-    uint256 constant senderSlotIndex = 50;
+    uint256 senderSlotIndex;
 
     uint256 public numHashes;
     bytes32[] public hashes;
@@ -29,6 +30,7 @@ contract RelayActor is StdUtils {
         xdm = _xdm;
         vm = _vm;
         doFail = _doFail;
+        senderSlotIndex = ForgeArtifacts.getSlot("OptimismPortal2", "l2Sender").slot;
     }
 
     /// @notice Relays a message to the `L1CrossDomainMessenger` with a random `version`,