ctb: Add echidna tests for Hashing

.changeset/light-buckets-flash.md

+---
+'@eth-optimism/contracts-bedrock': patch
+---
+
+Add echidna tests for hashing

.circleci/config.yml

@@ -843,6 +843,11 @@ workflows:
           echidna_target: metering
           requires:
             - bedrock-echidna-build
+      - bedrock-echidna-run:
+          name: Bedrock Echidna Hashing Test
+          echidna_target: hashing
+          requires:
+            - bedrock-echidna-build
       - op-bindings-build:
           requires:
             - yarn-monorepo

packages/contracts-bedrock/contracts/echidna/FuzzHashing.sol

+pragma solidity 0.8.15;
+
+import { Hashing } from "../libraries/Hashing.sol";
+import { Encoding } from "../libraries/Encoding.sol";
+
+contract EchidnaFuzzHashing {
+    bool failedCrossDomainHashHighVersion;
+    bool failedCrossDomainHashV0;
+    bool failedCrossDomainHashV1;
+
+    /**
+     * @notice Takes the necessary parameters to perform a cross domain hash with a randomly
+     * generated version. Only schema versions 0 and 1 are supported and all others should revert.
+     */
+    function testHashCrossDomainMessageHighVersion(
+        uint16 _version,
+        uint240 _nonce,
+        address _sender,
+        address _target,
+        uint256 _value,
+        uint256 _gasLimit,
+        bytes memory _data
+    ) public {
+        // generate the versioned nonce
+        uint256 encodedNonce = Encoding.encodeVersionedNonce(_nonce, _version);
+
+        // hash the cross domain message. we don't need to store the result since the function
+        // validates and should revert if an invalid version (>1) is encoded
+        Hashing.hashCrossDomainMessage(encodedNonce, _sender, _target, _value, _gasLimit, _data);
+
+        // check that execution never makes it this far for an invalid version
+        if (_version > 1) {
+            failedCrossDomainHashHighVersion = true;
+        }
+    }
+
+    /**
+     * @notice Takes the necessary parameters to perform a cross domain hash using the v0 schema
+     * and compares the output of a call to the unversioned function to the v0 function directly
+     */
+    function testHashCrossDomainMessageV0(
+        uint240 _nonce,
+        address _sender,
+        address _target,
+        uint256 _value,
+        uint256 _gasLimit,
+        bytes memory _data
+    ) public {
+        // generate the versioned nonce with the version set to 0
+        uint256 encodedNonce = Encoding.encodeVersionedNonce(_nonce, 0);
+
+        // hash the cross domain message using the unversioned and versioned functions for
+        // comparison
+        bytes32 sampleHash1 = Hashing.hashCrossDomainMessage(
+            encodedNonce,
+            _sender,
+            _target,
+            _value,
+            _gasLimit,
+            _data
+        );
+        bytes32 sampleHash2 = Hashing.hashCrossDomainMessageV0(
+            _target,
+            _sender,
+            _data,
+            encodedNonce
+        );
+
+        // check that the output of both functions matches
+        if (sampleHash1 != sampleHash2) {
+            failedCrossDomainHashV0 = true;
+        }
+    }
+
+    /**
+     * @notice Takes the necessary parameters to perform a cross domain hash using the v1 schema
+     * and compares the output of a call to the unversioned function to the v1 function directly
+     */
+    function testHashCrossDomainMessageV1(
+        uint240 _nonce,
+        address _sender,
+        address _target,
+        uint256 _value,
+        uint256 _gasLimit,
+        bytes memory _data
+    ) public {
+        // generate the versioned nonce with the version set to 1
+        uint256 encodedNonce = Encoding.encodeVersionedNonce(_nonce, 1);
+
+        // hash the cross domain message using the unversioned and versioned functions for
+        // comparison
+        bytes32 sampleHash1 = Hashing.hashCrossDomainMessage(
+            encodedNonce,
+            _sender,
+            _target,
+            _value,
+            _gasLimit,
+            _data
+        );
+        bytes32 sampleHash2 = Hashing.hashCrossDomainMessageV1(
+            encodedNonce,
+            _sender,
+            _target,
+            _value,
+            _gasLimit,
+            _data
+        );
+
+        // check that the output of both functions matches
+        if (sampleHash1 != sampleHash2) {
+            failedCrossDomainHashV1 = true;
+        }
+    }
+
+    function echidna_hash_xdomain_msg_high_version() public view returns (bool) {
+        // ASSERTION: A call to hashCrossDomainMessage will never succeed for a version > 1
+        return !failedCrossDomainHashHighVersion;
+    }
+
+    function echidna_hash_xdomain_msg_0() public view returns (bool) {
+        // ASSERTION: A call to hashCrossDomainMessage and hashCrossDomainMessageV0
+        // should always match when the version passed is 0
+        return !failedCrossDomainHashV0;
+    }
+
+    function echidna_hash_xdomain_msg_1() public view returns (bool) {
+        // ASSERTION: A call to hashCrossDomainMessage and hashCrossDomainMessageV1
+        // should always match when the version passed is 1
+        return !failedCrossDomainHashV1;
+    }
+}