feat: Remove SpokePool v2 functionality (#456)

* feat: Remove non-USS functionality from SpokePool

This PR showcases how we will remove all non-USS functionality in the spoke pools once all non-USS deposits are fills, fills are refunded, and roots are executed.

This PR reduces the bytecode significantly and means we can use the full optimizer runs setting for compiling these new contracts

* Remove Deposit and SlowRelay tests

Signed-off-by: nicholaspai <npai.nyc@gmail.com>

* WIP

* WIP

* Update utils.ts

* Add back Deposit functions

* add back legacy deposit unit tests

* Update hardhat.config.ts

* fix tests

* Update package.json

* fix

Signed-off-by: nicholaspai <npai.nyc@gmail.com>

* Add depositUSSNow, replace error strings with custom error types, fix tests

* Fix

* Fix tests

* Update SpokePool.Deposit.ts

* feat: Remove all "USS" references in contracts

This PR implements a simple find-and-replace of "USS" with "V3" to make it more clear that this is a new version of the Across protocol
that supports new features such as cross-chain token-swaps. USS is an internal code name for "Universal Settlement Service" but this is
not neccessariy the language that will be used to market this product. So, renaming to V3 makes these contract changes more of a blank
slate.

* Replace USS with V3

* Remove UBA references

* fix tests

* merge master

* fix tests

* change depositV3Now to take in exclusivity deadline

* Fix

* Update Ovm_SpokePool.sol

* Update Ovm_SpokePool.sol

* add back depositfor, remove special polygon spoke pool compiler rules

* update hardhat-zksolc

* Update test/SpokePool.Deposit.ts

Co-authored-by: Paul <108695806+pxrl@users.noreply.github.com>

* Update hardhat.config.ts

---------

Signed-off-by: nicholaspai <npai.nyc@gmail.com>
Co-authored-by: nicholaspai <npai.nyc@gmail.com>
Co-authored-by: nicholaspai <9457025+nicholaspai@users.noreply.github.com>

Author: pxrl

contracts/MerkleLib.sol

@@ -41,22 +41,6 @@ library MerkleLib {
         return MerkleProof.verify(proof, root, keccak256(abi.encode(refund)));
     }
 
-    /**
-     * @notice Verifies that a distribution is contained within a merkle root.
-     * @param root the merkle root.
-     * @param slowRelayFulfillment the relayData fulfillment struct.
-     * @param proof the merkle proof.
-     * @return bool to signal if the slow relay's proof correctly shows inclusion of the slow relay within the tree.
-     */
-    /// @custom:audit FOLLOWING FUNCTION TO BE DEPRECATED
-    function verifySlowRelayFulfillment(
-        bytes32 root,
-        SpokePoolInterface.SlowFill memory slowRelayFulfillment,
-        bytes32[] memory proof
-    ) internal pure returns (bool) {
-        return MerkleProof.verify(proof, root, keccak256(abi.encode(slowRelayFulfillment)));
-    }
-
     function verifyV3SlowRelayFulfillment(
         bytes32 root,
         V3SpokePoolInterface.V3SlowFill memory slowRelayFulfillment,

contracts/Ovm_SpokePool.sol

@@ -36,7 +36,10 @@ contract Ovm_SpokePool is SpokePool, CircleCCTPAdapter {
     address public l2Eth;
 
     // Address of the Optimism L2 messenger.
-    address public messenger;
+    address public constant MESSENGER = Lib_PredeployAddresses.L2_CROSS_DOMAIN_MESSENGER;
+    // @dev This storage slot is reserved to replace the old messenger public variable that has now been
+    // replaced by the above constant.
+    address private __deprecated_messenger;
 
     // Address of custom bridge used to bridge Synthetix-related assets like SNX.
     address private constant SYNTHETIX_BRIDGE = 0x136b1EC699c62b0606854056f02dC7Bb80482d63;
@@ -51,6 +54,8 @@ contract Ovm_SpokePool is SpokePool, CircleCCTPAdapter {
     event SetL1Gas(uint32 indexed newL1Gas);
     event SetL2TokenBridge(address indexed l2Token, address indexed tokenBridge);
 
+    error NotCrossDomainAdmin();
+
     /// @custom:oz-upgrades-unsafe-allow constructor
     constructor(
         address _wrappedNativeTokenAddress,
@@ -80,7 +85,6 @@ contract Ovm_SpokePool is SpokePool, CircleCCTPAdapter {
     ) public onlyInitializing {
         l1Gas = 5_000_000;
         __SpokePool_init(_initialDepositId, _crossDomainAdmin, _hubPool);
-        messenger = Lib_PredeployAddresses.L2_CROSS_DOMAIN_MESSENGER;
         //slither-disable-next-line missing-zero-check
         l2Eth = _l2Eth;
     }
@@ -169,10 +173,7 @@ contract Ovm_SpokePool is SpokePool, CircleCCTPAdapter {
 
     // Apply OVM-specific transformation to cross domain admin address on L1.
     function _requireAdminSender() internal view override {
-        require(
-            LibOptimismUpgradeable.crossChainSender(messenger) == crossDomainAdmin,
-            "OVM_XCHAIN: wrong sender of cross-domain message"
-        );
+        if (LibOptimismUpgradeable.crossChainSender(MESSENGER) != crossDomainAdmin) revert NotCrossDomainAdmin();
     }
 
     // Reserve storage slots for future versions of this base contract to add state variables without

contracts/Polygon_SpokePool.sol

@@ -51,6 +51,12 @@ contract Polygon_SpokePool is IFxMessageProcessor, SpokePool, CircleCCTPAdapter
     event SetPolygonTokenBridger(address indexed polygonTokenBridger);
     event ReceivedMessageFromL1(address indexed caller, address indexed rootMessageSender);
 
+    error CallValidatedAlreadySet();
+    error CallValidatedNotSet();
+    error DelegateCallFailed();
+    error NotHubPool();
+    error NotFxChild();
+
     // Note: validating calls this way ensures that strange calls coming from the fxChild won't be misinterpreted.
     // Put differently, just checking that msg.sender == fxChild is not sufficient.
     // All calls that have admin privileges must be fired from within the processMessageFromRoot method that's gone
@@ -59,7 +65,7 @@ contract Polygon_SpokePool is IFxMessageProcessor, SpokePool, CircleCCTPAdapter
     modifier validateInternalCalls() {
         // Make sure callValidated is set to True only once at beginning of processMessageFromRoot, which prevents
         // processMessageFromRoot from being re-entered.
-        require(!callValidated, "callValidated already set");
+        if (callValidated) revert CallValidatedAlreadySet();
 
         // This sets a variable indicating that we're now inside a validated call.
         // Note: this is used by other methods to ensure that this call has been validated by this method and is not
@@ -143,8 +149,8 @@ contract Polygon_SpokePool is IFxMessageProcessor, SpokePool, CircleCCTPAdapter
         bytes calldata data
     ) public validateInternalCalls {
         // Validation logic.
-        require(msg.sender == fxChild, "Not from fxChild");
-        require(rootMessageSender == crossDomainAdmin, "Not from mainnet admin");
+        if (msg.sender != fxChild) revert NotFxChild();
+        if (rootMessageSender != crossDomainAdmin) revert NotHubPool();
 
         // This uses delegatecall to take the information in the message and process it as a function call on this contract.
         /// This is a safe delegatecall because its made to address(this) so there is no risk of delegating to a
@@ -153,7 +159,7 @@ contract Polygon_SpokePool is IFxMessageProcessor, SpokePool, CircleCCTPAdapter
         /// @custom:oz-upgrades-unsafe-allow delegatecall
         (bool success, ) = address(this).delegatecall(data);
         //slither-disable-end low-level-calls
-        require(success, "delegatecall failed");
+        if (!success) revert DelegateCallFailed();
 
         emit ReceivedMessageFromL1(msg.sender, rootMessageSender);
     }
@@ -254,6 +260,6 @@ contract Polygon_SpokePool is IFxMessageProcessor, SpokePool, CircleCCTPAdapter
     // `processMessageFromRoot`. This prevents calling the admin functions from any other method besides
     // `processMessageFromRoot`.
     function _requireAdminSender() internal view override {
-        require(callValidated, "Must call processMessageFromRoot");
+        if (!callValidated) revert CallValidatedNotSet();
     }
 }