Fix ERC1155 supply tracking (#2956)

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

CHANGELOG.md

@@ -17,6 +17,10 @@
  * `Governor`: enable receiving Ether when a Timelock contract is not used. ([#2748](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2748))
  * `GovernorTimelockCompound`: fix ability to use Ether stored in the Timelock contract. ([#2748](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2748))
 
+## 4.3.3
+
+ * `ERC1155Supply`: Handle `totalSupply` changes by hooking into `_beforeTokenTransfer` to ensure consistency of balances and supply during `IERC1155Receiver.onERC1155Received` calls.
+
 ## 4.3.2 (2021-09-14)
 
  * `UUPSUpgradeable`: Add modifiers to prevent `upgradeTo` and `upgradeToAndCall` being executed on any contract that is not the active ERC1967 proxy. This prevents these functions being called on implementation contracts or minimal ERC1167 clones, in particular.

contracts/mocks/ERC1155SupplyMock.sol

@@ -8,37 +8,14 @@ import "../token/ERC1155/extensions/ERC1155Supply.sol";
 contract ERC1155SupplyMock is ERC1155Mock, ERC1155Supply {
     constructor(string memory uri) ERC1155Mock(uri) {}
 
-    function _mint(
-        address account,
-        uint256 id,
-        uint256 amount,
-        bytes memory data
-    ) internal virtual override(ERC1155, ERC1155Supply) {
-        super._mint(account, id, amount, data);
-    }
-
-    function _mintBatch(
+    function _beforeTokenTransfer(
+        address operator,
+        address from,
         address to,
         uint256[] memory ids,
         uint256[] memory amounts,
         bytes memory data
     ) internal virtual override(ERC1155, ERC1155Supply) {
-        super._mintBatch(to, ids, amounts, data);
-    }
-
-    function _burn(
-        address account,
-        uint256 id,
-        uint256 amount
-    ) internal virtual override(ERC1155, ERC1155Supply) {
-        super._burn(account, id, amount);
-    }
-
-    function _burnBatch(
-        address account,
-        uint256[] memory ids,
-        uint256[] memory amounts
-    ) internal virtual override(ERC1155, ERC1155Supply) {
-        super._burnBatch(account, ids, amounts);
+        super._beforeTokenTransfer(operator, from, to, ids, amounts, data);
     }
 }

contracts/token/ERC1155/extensions/ERC1155Supply.sol

@@ -31,56 +31,28 @@ abstract contract ERC1155Supply is ERC1155 {
     }
 
     /**
-     * @dev See {ERC1155-_mint}.
+     * @dev See {ERC1155-_beforeTokenTransfer}.
      */
-    function _mint(
-        address account,
-        uint256 id,
-        uint256 amount,
-        bytes memory data
-    ) internal virtual override {
-        super._mint(account, id, amount, data);
-        _totalSupply[id] += amount;
-    }
-
-    /**
-     * @dev See {ERC1155-_mintBatch}.
-     */
-    function _mintBatch(
+    function _beforeTokenTransfer(
+        address operator,
+        address from,
         address to,
         uint256[] memory ids,
         uint256[] memory amounts,
         bytes memory data
     ) internal virtual override {
-        super._mintBatch(to, ids, amounts, data);
+        super._beforeTokenTransfer(operator, from, to, ids, amounts, data);
+
+        if (from == address(0)) {
             for (uint256 i = 0; i < ids.length; ++i) {
                 _totalSupply[ids[i]] += amounts[i];
             }
         }
 
-    /**
-     * @dev See {ERC1155-_burn}.
-     */
-    function _burn(
-        address account,
-        uint256 id,
-        uint256 amount
-    ) internal virtual override {
-        super._burn(account, id, amount);
-        _totalSupply[id] -= amount;
-    }
-
-    /**
-     * @dev See {ERC1155-_burnBatch}.
-     */
-    function _burnBatch(
-        address account,
-        uint256[] memory ids,
-        uint256[] memory amounts
-    ) internal virtual override {
-        super._burnBatch(account, ids, amounts);
+        if (to == address(0)) {
             for (uint256 i = 0; i < ids.length; ++i) {
                 _totalSupply[ids[i]] -= amounts[i];
             }
         }
     }
+}