Merge upstream release-v4.5 into patched/release-v4.5

CHANGELOG.md

@@ -14,7 +14,10 @@
  * `Base64`: add a library to parse bytes into base64 strings using `encode(bytes memory)` function, and provide examples to show how to use to build URL-safe `tokenURIs`. ([#2884](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2884))
  * `ERC20`: reduce allowance before triggering transfer. ([#3056](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3056))
  * `ERC20`: do not update allowance on `transferFrom` when allowance is `type(uint256).max`. ([#3085](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3085))
+ * `ERC20`: add a `_spendAllowance` internal function. ([#3170](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3170))
+ * `ERC20Burnable`: do not update allowance on `burnFrom` when allowance is `type(uint256).max`. ([#3170](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3170))
  * `ERC777`: do not update allowance on `transferFrom` when allowance is `type(uint256).max`. ([#3085](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3085))
+ * `ERC777`: add a `_spendAllowance` internal function. ([#3170](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3170))
  * `SignedMath`: a new signed version of the Math library with `max`, `min`,  and `average`. ([#2686](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2686))
  * `SignedMath`: add a `abs(int256)` method that returns the unsigned absolute value of a signed value. ([#2984](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2984))
  * `ERC1967Upgrade`: Refactor the secure upgrade to use `ERC1822` instead of the previous rollback mechanism. This reduces code complexity and attack surface with similar security guarantees. ([#3021](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3021))

contracts/token/ERC20/ERC20.sol

@@ -107,11 +107,12 @@ contract ERC20 is Context, IERC20, IERC20Metadata {
      *
      * Requirements:
      *
-     * - `recipient` cannot be the zero address.
+     * - `to` cannot be the zero address.
      * - the caller must have a balance of at least `amount`.
      */
-    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
-        _transfer(_msgSender(), recipient, amount);
+    function transfer(address to, uint256 amount) public virtual override returns (bool) {
+        address owner = _msgSender();
+        _transfer(owner, to, amount);
         return true;
     }
 
@@ -133,7 +134,8 @@ contract ERC20 is Context, IERC20, IERC20Metadata {
      * - `spender` cannot be the zero address.
      */
     function approve(address spender, uint256 amount) public virtual override returns (bool) {
-        _approve(_msgSender(), spender, amount);
+        address owner = _msgSender();
+        _approve(owner, spender, amount);
         return true;
     }
 
@@ -148,26 +150,19 @@ contract ERC20 is Context, IERC20, IERC20Metadata {
      *
      * Requirements:
      *
-     * - `sender` and `recipient` cannot be the zero address.
-     * - `sender` must have a balance of at least `amount`.
-     * - the caller must have allowance for ``sender``'s tokens of at least
+     * - `from` and `to` cannot be the zero address.
+     * - `from` must have a balance of at least `amount`.
+     * - the caller must have allowance for ``from``'s tokens of at least
      * `amount`.
      */
     function transferFrom(
-        address sender,
-        address recipient,
+        address from,
+        address to,
         uint256 amount
     ) public virtual override returns (bool) {
-        uint256 currentAllowance = _allowances[sender][_msgSender()];
-        if (currentAllowance != type(uint256).max) {
-            require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
-            unchecked {
-                _approve(sender, _msgSender(), currentAllowance - amount);
-            }
-        }
-
-        _transfer(sender, recipient, amount);
-
+        address spender = _msgSender();
+        _spendAllowance(from, spender, amount);
+        _transfer(from, to, amount);
         return true;
     }
 
@@ -184,7 +179,8 @@ contract ERC20 is Context, IERC20, IERC20Metadata {
      * - `spender` cannot be the zero address.
      */
     function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
-        _approve(_msgSender(), spender, _allowances[_msgSender()][spender] + addedValue);
+        address owner = _msgSender();
+        _approve(owner, spender, _allowances[owner][spender] + addedValue);
         return true;
     }
 
@@ -203,10 +199,11 @@ contract ERC20 is Context, IERC20, IERC20Metadata {
      * `subtractedValue`.
      */
     function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
-        uint256 currentAllowance = _allowances[_msgSender()][spender];
+        address owner = _msgSender();
+        uint256 currentAllowance = _allowances[owner][spender];
         require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
         unchecked {
-            _approve(_msgSender(), spender, currentAllowance - subtractedValue);
+            _approve(owner, spender, currentAllowance - subtractedValue);
         }
 
         return true;
@@ -222,30 +219,30 @@ contract ERC20 is Context, IERC20, IERC20Metadata {
      *
      * Requirements:
      *
-     * - `sender` cannot be the zero address.
-     * - `recipient` cannot be the zero address.
-     * - `sender` must have a balance of at least `amount`.
+     * - `from` cannot be the zero address.
+     * - `to` cannot be the zero address.
+     * - `from` must have a balance of at least `amount`.
      */
     function _transfer(
-        address sender,
-        address recipient,
+        address from,
+        address to,
         uint256 amount
     ) internal virtual {
-        require(sender != address(0), "ERC20: transfer from the zero address");
-        require(recipient != address(0), "ERC20: transfer to the zero address");
+        require(from != address(0), "ERC20: transfer from the zero address");
+        require(to != address(0), "ERC20: transfer to the zero address");
 
-        _beforeTokenTransfer(sender, recipient, amount);
+        _beforeTokenTransfer(from, to, amount);
 
-        uint256 senderBalance = _balances[sender];
-        require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
+        uint256 fromBalance = _balances[from];
+        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
         unchecked {
-            _balances[sender] = senderBalance - amount;
+            _balances[from] = fromBalance - amount;
         }
-        _balances[recipient] += amount;
+        _balances[to] += amount;
 
-        emit Transfer(sender, recipient, amount);
+        emit Transfer(from, to, amount);
 
-        _afterTokenTransfer(sender, recipient, amount);
+        _afterTokenTransfer(from, to, amount);
     }
 
     /** @dev Creates `amount` tokens and assigns them to `account`, increasing
@@ -323,6 +320,28 @@ contract ERC20 is Context, IERC20, IERC20Metadata {
     }
 
     /**
+     * @dev Spend `amount` form the allowance of `owner` toward `spender`.
+     *
+     * Does not update the allowance amount in case of infinite allowance.
+     * Revert if not enough allowance is available.
+     *
+     * Might emit an {Approval} event.
+     */
+    function _spendAllowance(
+        address owner,
+        address spender,
+        uint256 amount
+    ) internal virtual {
+        uint256 currentAllowance = allowance(owner, spender);
+        if (currentAllowance != type(uint256).max) {
+            require(currentAllowance >= amount, "ERC20: insufficient allowance");
+            unchecked {
+                _approve(owner, spender, currentAllowance - amount);
+            }
+        }
+    }
+
+    /**
      * @dev Hook that is called before any transfer of tokens. This includes
      * minting and burning.
      *

contracts/token/ERC20/IERC20.sol

@@ -18,13 +18,13 @@ interface IERC20 {
     function balanceOf(address account) external view returns (uint256);
 
     /**
-     * @dev Moves `amount` tokens from the caller's account to `recipient`.
+     * @dev Moves `amount` tokens from the caller's account to `to`.
      *
      * Returns a boolean value indicating whether the operation succeeded.
      *
      * Emits a {Transfer} event.
      */
-    function transfer(address recipient, uint256 amount) external returns (bool);
+    function transfer(address to, uint256 amount) external returns (bool);
 
     /**
      * @dev Returns the remaining number of tokens that `spender` will be
@@ -52,7 +52,7 @@ interface IERC20 {
     function approve(address spender, uint256 amount) external returns (bool);
 
     /**
-     * @dev Moves `amount` tokens from `sender` to `recipient` using the
+     * @dev Moves `amount` tokens from `from` to `to` using the
      * allowance mechanism. `amount` is then deducted from the caller's
      * allowance.
      *
@@ -61,8 +61,8 @@ interface IERC20 {
      * Emits a {Transfer} event.
      */
     function transferFrom(
-        address sender,
-        address recipient,
+        address from,
+        address to,
         uint256 amount
     ) external returns (bool);
 

contracts/token/ERC20/extensions/ERC20Burnable.sol

@@ -33,11 +33,7 @@ abstract contract ERC20Burnable is Context, ERC20 {
      * `amount`.
      */
     function burnFrom(address account, uint256 amount) public virtual {
-        uint256 currentAllowance = allowance(account, _msgSender());
-        require(currentAllowance >= amount, "ERC20: burn amount exceeds allowance");
-        unchecked {
-            _approve(account, _msgSender(), currentAllowance - amount);
-        }
+        _spendAllowance(account, _msgSender(), amount);
         _burn(account, amount);
     }
 }

contracts/token/ERC777/ERC777.sol

@@ -293,13 +293,7 @@ contract ERC777 is Context, IERC777, IERC20 {
 
         _callTokensToSend(spender, holder, recipient, amount, "", "");
 
-        uint256 currentAllowance = _allowances[holder][spender];
-        if (currentAllowance != type(uint256).max) {
-            require(currentAllowance >= amount, "ERC777: transfer amount exceeds allowance");
-            unchecked {
-                _approve(holder, spender, currentAllowance - amount);
-            }
-        }
+        _spendAllowance(holder, spender, amount);
 
         _move(spender, holder, recipient, amount, "", "");
 
@@ -527,6 +521,28 @@ contract ERC777 is Context, IERC777, IERC20 {
     }
 
     /**
+     * @dev Spend `amount` form the allowance of `owner` toward `spender`.
+     *
+     * Does not update the allowance amount in case of infinite allowance.
+     * Revert if not enough allowance is available.
+     *
+     * Might emit an {Approval} event.
+     */
+    function _spendAllowance(
+        address owner,
+        address spender,
+        uint256 amount
+    ) internal virtual {
+        uint256 currentAllowance = allowance(owner, spender);
+        if (currentAllowance != type(uint256).max) {
+            require(currentAllowance >= amount, "ERC777: insufficient allowance");
+            unchecked {
+                _approve(owner, spender, currentAllowance - amount);
+            }
+        }
+    }
+
+    /**
      * @dev Hook that is called before any token transfer. This includes
      * calls to {send}, {transfer}, {operatorSend}, minting and burning.
      *

test/token/ERC20/ERC20.behavior.js

@@ -108,7 +108,7 @@ function shouldBehaveLikeERC20 (errorPrefix, initialSupply, initialHolder, recip
             it('reverts', async function () {
               await expectRevert(
                 this.token.transferFrom(tokenOwner, to, amount, { from: spender }),
-                `${errorPrefix}: transfer amount exceeds allowance`,
+                `${errorPrefix}: insufficient allowance`,
               );
             });
           });

test/token/ERC20/extensions/ERC20Burnable.behavior.js

@@ -98,7 +98,7 @@ function shouldBehaveLikeERC20Burnable (owner, initialBalance, [burner]) {
       it('reverts', async function () {
         await this.token.approve(burner, allowance, { from: owner });
         await expectRevert(this.token.burnFrom(owner, allowance.addn(1), { from: burner }),
-          'ERC20: burn amount exceeds allowance',
+          'ERC20: insufficient allowance',
         );
       });
     });

test/token/ERC20/extensions/ERC20Wrapper.test.js

@@ -59,7 +59,7 @@ contract('ERC20', function (accounts) {
     it('missing approval', async function () {
       await expectRevert(
         this.token.depositFor(initialHolder, initialSupply, { from: initialHolder }),
-        'ERC20: transfer amount exceeds allowance',
+        'ERC20: insufficient allowance',
       );
     });