Merge branch 'master' into feature/SignatureChecker

CHANGELOG.md

@@ -4,6 +4,7 @@
 
  * `IERC20Metadata`: add a new extended interface that includes the optional `name()`, `symbol()` and `decimals()` functions. ([#2561](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2561))
  * `ERC777`: make reception acquirement optional in `_mint`. ([#2552](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2552))
+ * `ERC20Permit`: add a `_useNonce` to enable further usage of ERC712 signatures. ([#2565](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2565))
  * `SignatureChecker`: add a signature verification library that supports both EOA and ERC1271 compliant contracts as signers. ([#2532](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2532))
 
 ## Unreleased

contracts/token/ERC20/ERC20.sol

@@ -46,7 +46,7 @@ contract ERC20 is Context, IERC20, IERC20Metadata {
      * The defaut value of {decimals} is 18. To select a different value for
      * {decimals} you should overload it.
      *
-     * All three of these values are immutable: they can only be set once during
+     * All two of these values are immutable: they can only be set once during
      * construction.
      */
     constructor (string memory name_, string memory symbol_) {

contracts/token/ERC20/extensions/draft-ERC20Permit.sol

@@ -47,7 +47,7 @@ abstract contract ERC20Permit is ERC20, IERC20Permit, EIP712 {
                 owner,
                 spender,
                 value,
-                _nonces[owner].current(),
+                _useNonce(owner),
                 deadline
             )
         );
@@ -57,14 +57,13 @@ abstract contract ERC20Permit is ERC20, IERC20Permit, EIP712 {
         address signer = ECDSA.recover(hash, v, r, s);
         require(signer == owner, "ERC20Permit: invalid signature");
 
-        _nonces[owner].increment();
         _approve(owner, spender, value);
     }
 
     /**
      * @dev See {IERC20Permit-nonces}.
      */
-    function nonces(address owner) public view override returns (uint256) {
+    function nonces(address owner) public view virtual override returns (uint256) {
         return _nonces[owner].current();
     }
 
@@ -75,4 +74,13 @@ abstract contract ERC20Permit is ERC20, IERC20Permit, EIP712 {
     function DOMAIN_SEPARATOR() external view override returns (bytes32) {
         return _domainSeparatorV4();
     }
+
+    /**
+     * @dev "Consume a nonce": return the current value and increment.
+     */
+    function _useNonce(address owner) internal virtual returns (uint256 current) {
+        Counters.Counter storage nonce = _nonces[owner];
+        current = nonce.current();
+        nonce.increment();
+    }
 }

contracts/token/ERC20/extensions/draft-IERC20Permit.sol

@@ -7,13 +7,13 @@ pragma solidity ^0.8.0;
  * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
  *
  * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
- * presenting a message signed by the account. By not relying on `{IERC20-approve}`, the token holder account doesn't
+ * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
  * need to send a transaction, and thus is not required to hold Ether at all.
  */
 interface IERC20Permit {
     /**
-     * @dev Sets `value` as the allowance of `spender` over `owner`'s tokens,
-     * given `owner`'s signed approval.
+     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
+     * given ``owner``'s signed approval.
      *
      * IMPORTANT: The same issues {IERC20-approve} has related to transaction
      * ordering also apply here.
@@ -44,7 +44,7 @@ interface IERC20Permit {
     function nonces(address owner) external view returns (uint256);
 
     /**
-     * @dev Returns the domain separator used in the encoding of the signature for `permit`, as defined by {EIP712}.
+     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
      */
     // solhint-disable-next-line func-name-mixedcase
     function DOMAIN_SEPARATOR() external view returns (bytes32);

contracts/utils/cryptography/MerkleProof.sol

@@ -3,7 +3,13 @@
 pragma solidity ^0.8.0;
 
 /**
- * @dev These functions deal with verification of Merkle trees (hash trees),
+ * @dev These functions deal with verification of Merkle Trees proofs.
+ *
+ * The proofs can be generated using the JavaScript library
+ * https://github.com/miguelmota/merkletreejs[merkletreejs].
+ * Note: the hashing algorithm should be keccak256 and pair sorting should be enabled.
+ *
+ * See `test/utils/cryptography/MerkleProof.test.js` for some examples.
  */
 library MerkleProof {
     /**

contracts/utils/structs/EnumerableSet.sol

@@ -89,7 +89,7 @@ library EnumerableSet {
             // Move the last value to the index where the value to delete is
             set._values[toDeleteIndex] = lastvalue;
             // Update the index for the moved value
-            set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based
+            set._indexes[lastvalue] = valueIndex; // Replace lastvalue's index to valueIndex
 
             // Delete the slot where the moved value was stored
             set._values.pop();

package.json

@@ -66,15 +66,16 @@
     "ethereumjs-wallet": "^1.0.1",
     "hardhat": "^2.0.6",
     "hardhat-gas-reporter": "^1.0.4",
+    "keccak256": "^1.0.2",
     "lodash.startcase": "^4.4.0",
     "lodash.zip": "^4.2.0",
+    "merkletreejs": "^0.2.13",
     "micromatch": "^4.0.2",
     "mocha": "^8.0.1",
     "rimraf": "^3.0.2",
     "solhint": "^3.2.0",
     "solidity-coverage": "^0.7.11",
     "solidity-docgen": "^0.5.3",
     "web3": "^1.3.0"
-  },
-  "dependencies": {}
+  }
 }