Add option to issue tokens

contracts/sfc/ConstantsManager.sol

@@ -37,6 +37,10 @@ contract ConstantsManager is Ownable {
     // Zero to disable validators deactivation by this metric.
     uint64 public minAverageUptime;
 
+    // The address of the recipient that receives issued tokens
+    // as a counterparty to the burnt FTM tokens
+    address public issuedTokensRecipient;
+
     /**
      * @dev Given value is too small
      */
@@ -177,4 +181,8 @@ contract ConstantsManager is Ownable {
         }
         minAverageUptime = v;
     }
+
+    function updateIssuedTokensRecipient(address v) external virtual onlyOwner {
+        issuedTokensRecipient = v;
+    }
 }

contracts/sfc/NodeDriverAuth.sol

@@ -83,9 +83,6 @@ contract NodeDriverAuth is OwnableUpgradeable, UUPSUpgradeable {
 
     /// Mint native token. To be used by SFC for minting validators rewards.
     function incBalance(address acc, uint256 diff) external onlySFC {
-        if (acc != address(sfc)) {
-            revert RecipientNotSFC();
-        }
         driver.setBalance(acc, address(acc).balance + diff);
     }
 

contracts/sfc/SFC.sol

@@ -459,6 +459,15 @@ contract SFC is OwnableUpgradeable, UUPSUpgradeable, Version {
         _burnFTM(amount);
     }
 
+    /// Issue tokens to the issued tokens recipient as a counterparty to the burnt FTM tokens.
+    function issueTokens(uint256 amount) external onlyOwner {
+        if (c.issuedTokensRecipient() == address(0)) {
+            revert ZeroAddress();
+        }
+        node.incBalance(c.issuedTokensRecipient(), amount);
+        totalSupply += amount;
+    }
+
     /// Update treasury address.
     function updateTreasuryAddress(address v) external onlyOwner {
         treasuryAddress = v;

test/SFC.ts

@@ -131,6 +131,30 @@ describe('SFC', () => {
     });
   });
 
+  describe('Issue tokens', () => {
+    it('Should revert when not owner', async function () {
+      await expect(this.sfc.connect(this.user).issueTokens(ethers.parseEther('100'))).to.be.revertedWithCustomError(
+        this.sfc,
+        'OwnableUnauthorizedAccount',
+      );
+    });
+
+    it('Should revert when recipient is not set', async function () {
+      await expect(this.sfc.connect(this.owner).issueTokens(ethers.parseEther('100'))).to.be.revertedWithCustomError(
+        this.sfc,
+        'ZeroAddress',
+      );
+    });
+
+    it('Should succeed and issue tokens', async function () {
+      await this.constants.updateIssuedTokensRecipient(this.user);
+      const supply = await this.sfc.totalSupply();
+      const amount = ethers.parseEther('100');
+      await this.sfc.connect(this.owner).issueTokens(amount);
+      expect(await this.sfc.totalSupply()).to.equal(supply + amount);
+    });
+  });
+
   describe('Create validator', () => {
     const validatorsFixture = async () => {
       const validatorPubKey =