Replace OZ EIP712

.forge-snapshots/PositionManager_multicall_initialize_mint.snap

@@ -1 +1 @@
-416516
+416538

.forge-snapshots/PositionManager_permit.snap

@@ -1 +1 @@
-79585
+79660

.forge-snapshots/PositionManager_permit_secondPosition.snap

@@ -1 +1 @@
-62497
+62572

.forge-snapshots/PositionManager_permit_twice.snap

@@ -1 +1 @@
-45397
+45472

remappings.txt

@@ -1,5 +1,4 @@
 @uniswap/v4-core/=lib/v4-core/
-@openzeppelin/=lib/v4-core/lib/openzeppelin-contracts/
 forge-gas-snapshot/=lib/v4-core/lib/forge-gas-snapshot/src/
 ds-test/=lib/v4-core/lib/forge-std/lib/ds-test/src/
 forge-std/=lib/v4-core/lib/forge-std/src/

src/base/EIP712.sol

@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.20;
+
+import {IEIP712} from "../interfaces/IEIP712.sol";
+
+/// @notice Generic EIP712 implementation
+/// @dev Maintains cross-chain replay protection in the event of a fork
+/// @dev Reference: https://github.com/Uniswap/permit2/blob/main/src/EIP712.sol
+/// @dev Reference: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/cryptography/EIP712.sol
+contract EIP712 is IEIP712 {
+    // Cache the domain separator as an immutable value, but also store the chain id that it
+    // corresponds to, in order to invalidate the cached domain separator if the chain id changes.
+    bytes32 private immutable _CACHED_DOMAIN_SEPARATOR;
+    uint256 private immutable _CACHED_CHAIN_ID;
+    address private immutable _CACHED_THIS;
+    bytes32 private immutable _HASHED_NAME;
+    bytes32 private immutable _HASHED_VERSION;
+
+    bytes32 private constant _TYPE_HASH =
+        keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)");
+
+    constructor(string memory name, string memory version) {
+        _HASHED_NAME = keccak256(bytes(name));
+        _HASHED_VERSION = keccak256(bytes(version));
+
+        _CACHED_CHAIN_ID = block.chainid;
+        _CACHED_DOMAIN_SEPARATOR = _buildDomainSeparator();
+        _CACHED_THIS = address(this);
+    }
+
+    /// @notice Returns the domain separator for the current chain.
+    /// @dev Uses cached version if chainid and address are unchanged from construction.
+    function DOMAIN_SEPARATOR() public view override returns (bytes32) {
+        return address(this) == _CACHED_THIS && block.chainid == _CACHED_CHAIN_ID
+            ? _CACHED_DOMAIN_SEPARATOR
+            : _buildDomainSeparator();
+    }
+
+    /// @notice Builds a domain separator using the current chainId and contract address.
+    function _buildDomainSeparator() private view returns (bytes32) {
+        return keccak256(abi.encode(_TYPE_HASH, _HASHED_NAME, _HASHED_VERSION, block.chainid, address(this)));
+    }
+
+    /// @notice Creates an EIP-712 typed data hash
+    function _hashTypedData(bytes32 dataHash) internal view returns (bytes32) {
+        return keccak256(abi.encodePacked("\x19\x01", DOMAIN_SEPARATOR(), dataHash));
+    }
+}

src/base/ERC721Permit.sol

@@ -3,7 +3,7 @@ pragma solidity ^0.8.24;
 
 import {IERC721} from "forge-std/interfaces/IERC721.sol";
 import {ERC721} from "solmate/src/tokens/ERC721.sol";
-import {EIP712} from "@openzeppelin/contracts/utils/cryptography/EIP712.sol";
+import {EIP712} from "./EIP712.sol";
 import {ERC721PermitHashLibrary} from "../libraries/ERC721PermitHash.sol";
 import {SignatureVerification} from "permit2/src/libraries/SignatureVerification.sol";
 
@@ -21,11 +21,6 @@ abstract contract ERC721Permit is ERC721, IERC721Permit, EIP712, UnorderedNonce
         EIP712(name_, version_)
     {}
 
-    /// @inheritdoc IERC721Permit
-    function DOMAIN_SEPARATOR() external view returns (bytes32) {
-        return _domainSeparatorV4();
-    }
-
     /// @inheritdoc IERC721Permit
     function permit(address spender, uint256 tokenId, uint256 deadline, uint256 nonce, bytes calldata signature)
         external
@@ -37,7 +32,7 @@ abstract contract ERC721Permit is ERC721, IERC721Permit, EIP712, UnorderedNonce
         if (spender == owner) revert NoSelfPermit();
 
         bytes32 hash = ERC721PermitHashLibrary.hash(spender, tokenId, nonce, deadline);
-        signature.verify(_hashTypedDataV4(hash), owner);
+        signature.verify(_hashTypedData(hash), owner);
 
         _useUnorderedNonce(owner, nonce);
         _approve(owner, spender, tokenId);

src/interfaces/IEIP712.sol

@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+interface IEIP712 {
+    function DOMAIN_SEPARATOR() external view returns (bytes32);
+}

src/interfaces/IERC721Permit.sol

@@ -8,10 +8,6 @@ interface IERC721Permit {
     error NoSelfPermit();
     error Unauthorized();
 
-    /// @notice The domain separator used in the permit signature
-    /// @return The domain seperator used in encoding of permit signature
-    function DOMAIN_SEPARATOR() external view returns (bytes32);
-
     /// @notice Approve of a specific token ID for spending by spender via signature
     /// @param spender The account that is being approved
     /// @param tokenId The ID of the token that is being approved for spending

test/ERC721Permit.t.sol

@@ -69,7 +69,7 @@ contract ERC721PermitTest is Test {
 
     function test_domainSeparator() public view {
         assertEq(
-            IERC721Permit(address(erc721Permit)).DOMAIN_SEPARATOR(),
+            erc721Permit.DOMAIN_SEPARATOR(),
             keccak256(
                 abi.encode(
                     keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"),

test/position-managers/Permit.t.sol

@@ -60,7 +60,7 @@ contract PermitTest is Test, PosmTestSetup {
 
     function test_domainSeparator() public view {
         assertEq(
-            IERC721Permit(address(lpm)).DOMAIN_SEPARATOR(),
+            ERC721Permit(address(lpm)).DOMAIN_SEPARATOR(),
             keccak256(
                 abi.encode(
                     keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"),