Merge pull request #49 from skalenetwork/bug-on-update

Fix bug in transfer to self

Author: eduv09

contracts/ConfidentialToken.sol

@@ -322,6 +322,12 @@ contract ConfidentialToken is EIP3009, ERC20Permit, AccessManaged, IConfidential
     )
         internal
     {
+        if (from == to) {
+            _setBalance(from, fromBalance);
+            _onUpdate(from, to, value);
+            return;
+        }
+
         uint256 updatedFromBalance = fromBalance;
         uint256 updatedToBalance = toBalance;
 

test/ConfidentialToken.ts

@@ -1,7 +1,7 @@
 // cspell:words ECIES
 
 import { ethers } from "hardhat";
-import { cleanMintableDeployment } from "./tools/fixtures";
+import { cleanMintableDeployment, withMintedTokens } from "./tools/fixtures";
 import "chai/register-should";
 import { getPublicKey } from "./tools/cryptography";
 import { balanceOf } from "./tools/helpers";
@@ -226,4 +226,23 @@ describe("ConfidentialToken", () => {
         // Real balance should stay the same
         expect(realBalanceBefore).to.equal(realBalanceAfter);
     });
+
+    it("transfer to self should not change balance", async () => {
+        const amount = ethers.parseEther("1.0");
+        const [owner] = await ethers.getSigners();
+        const { token, bite } = await withMintedTokens();
+
+        await token.connect(owner).setViewerPublicKey(
+            await getPublicKey(owner)
+        );
+        await bite.sendCallback();
+
+        const balanceBefore = await balanceOf(token, bite, owner);
+
+        await token.connect(owner).transfer(owner, amount);
+        await bite.sendCallback();
+
+        const balanceAfter = await balanceOf(token, bite, owner);
+        balanceAfter.should.be.equal(balanceBefore);
+    });
 });