Mint ERC777 without reception ack (#2552)

CHANGELOG.md

@@ -21,6 +21,7 @@
  * `AccessControl`: Added ERC165 interface detection. ([#2562](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2562))
  * `AccessControlEnumerable`: Fixed `renounceRole` not updated underlying set. ([#2572](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2572))
  * `ERC1155`: Make `uri` public so overloading function can call it using super. ([#2576](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2576))
+ * `ERC777`: Make reception acquirement optional in `_mint`. ([#2552](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2552))
 
 ### How to upgrade from 3.x
 

contracts/mocks/ERC777Mock.sol

@@ -27,6 +27,16 @@ contract ERC777Mock is Context, ERC777 {
         _mint(to, amount, userData, operatorData);
     }
 
+    function mintInternalExtended (
+        address to,
+        uint256 amount,
+        bytes memory userData,
+        bytes memory operatorData,
+        bool requireReceptionAck
+    ) public {
+        _mint(to, amount, userData, operatorData, requireReceptionAck);
+    }
+
     function approveInternal(address holder, address spender, uint256 value) public {
         _approve(holder, spender, value);
     }

contracts/token/ERC777/ERC777.sol

@@ -312,6 +312,37 @@ contract ERC777 is Context, IERC777, IERC20 {
     )
         internal
         virtual
+    {
+        _mint(account, amount, userData, operatorData, true);
+    }
+
+    /**
+     * @dev Creates `amount` tokens and assigns them to `account`, increasing
+     * the total supply.
+     *
+     * If `requireReceptionAck` is set to true, and if a send hook is
+     * registered for `account`, the corresponding function will be called with
+     * `operator`, `data` and `operatorData`.
+     *
+     * See {IERC777Sender} and {IERC777Recipient}.
+     *
+     * Emits {Minted} and {IERC20-Transfer} events.
+     *
+     * Requirements
+     *
+     * - `account` cannot be the zero address.
+     * - if `account` is a contract, it must implement the {IERC777Recipient}
+     * interface.
+     */
+    function _mint(
+        address account,
+        uint256 amount,
+        bytes memory userData,
+        bytes memory operatorData,
+        bool requireReceptionAck
+    )
+        internal
+        virtual
     {
         require(account != address(0), "ERC777: mint to the zero address");
 
@@ -323,7 +354,7 @@ contract ERC777 is Context, IERC777, IERC20 {
         _totalSupply += amount;
         _balances[account] += amount;
 
-        _callTokensReceived(operator, address(0), account, amount, userData, operatorData, true);
+        _callTokensReceived(operator, address(0), account, amount, userData, operatorData, requireReceptionAck);
 
         emit Minted(operator, account, amount, userData, operatorData);
         emit Transfer(address(0), account, amount);

test/token/ERC777/ERC777.test.js

@@ -171,6 +171,133 @@ contract('ERC777', function (accounts) {
           shouldBehaveLikeERC777InternalMint(to, operator, amount, data, operatorData);
         });
       });
+
+      describe('mint (internal extended)', function () {
+        const amount = new BN('5');
+
+        context('to anyone', function () {
+          beforeEach(async function () {
+            this.recipient = anyone;
+          });
+
+          context('with default operator', function () {
+            const operator = defaultOperatorA;
+
+            it('without requireReceptionAck', async function () {
+              await this.token.mintInternalExtended(
+                this.recipient,
+                amount,
+                data,
+                operatorData,
+                false,
+                { from: operator },
+              );
+            });
+
+            it('with requireReceptionAck', async function () {
+              await this.token.mintInternalExtended(
+                this.recipient,
+                amount,
+                data,
+                operatorData,
+                true,
+                { from: operator },
+              );
+            });
+          });
+
+          context('with non operator', function () {
+            const operator = newOperator;
+
+            it('without requireReceptionAck', async function () {
+              await this.token.mintInternalExtended(
+                this.recipient,
+                amount,
+                data,
+                operatorData,
+                false,
+                { from: operator },
+              );
+            });
+
+            it('with requireReceptionAck', async function () {
+              await this.token.mintInternalExtended(
+                this.recipient,
+                amount,
+                data,
+                operatorData,
+                true,
+                { from: operator },
+              );
+            });
+          });
+        });
+
+        context('to non ERC777TokensRecipient implementer', function () {
+          beforeEach(async function () {
+            this.tokensRecipientImplementer = await ERC777SenderRecipientMock.new();
+            this.recipient = this.tokensRecipientImplementer.address;
+          });
+
+          context('with default operator', function () {
+            const operator = defaultOperatorA;
+
+            it('without requireReceptionAck', async function () {
+              await this.token.mintInternalExtended(
+                this.recipient,
+                amount,
+                data,
+                operatorData,
+                false,
+                { from: operator },
+              );
+            });
+
+            it('with requireReceptionAck', async function () {
+              await expectRevert(
+                this.token.mintInternalExtended(
+                  this.recipient,
+                  amount,
+                  data,
+                  operatorData,
+                  true,
+                  { from: operator },
+                ),
+                'ERC777: token recipient contract has no implementer for ERC777TokensRecipient',
+              );
+            });
+          });
+
+          context('with non operator', function () {
+            const operator = newOperator;
+
+            it('without requireReceptionAck', async function () {
+              await this.token.mintInternalExtended(
+                this.recipient,
+                amount,
+                data,
+                operatorData,
+                false,
+                { from: operator },
+              );
+            });
+
+            it('with requireReceptionAck', async function () {
+              await expectRevert(
+                this.token.mintInternalExtended(
+                  this.recipient,
+                  amount,
+                  data,
+                  operatorData,
+                  true,
+                  { from: operator },
+                ),
+                'ERC777: token recipient contract has no implementer for ERC777TokensRecipient',
+              );
+            });
+          });
+        });
+      });
     });
 
     describe('operator management', function () {