fix: Avoid emitting events when balanceIncrease is zero (#745)

Author: miguelmtzinf

contracts/protocol/tokenization/base/ScaledBalanceTokenBase.sol

@@ -154,8 +154,10 @@ abstract contract ScaledBalanceTokenBase is MintableIncentivizedERC20, IScaledBa
 
     super._transfer(sender, recipient, amount.rayDiv(index).toUint128());
 
-    emit Transfer(address(0), sender, senderBalanceIncrease);
-    emit Mint(_msgSender(), sender, senderBalanceIncrease, senderBalanceIncrease, index);
+    if (senderBalanceIncrease > 0) {
+      emit Transfer(address(0), sender, senderBalanceIncrease);
+      emit Mint(_msgSender(), sender, senderBalanceIncrease, senderBalanceIncrease, index);
+    }
 
     if (recipientBalanceIncrease > 0) {
       emit Transfer(address(0), recipient, recipientBalanceIncrease);

test-suites/helpers/utils/tokenization-events.ts

@@ -216,18 +216,20 @@ export const transfer = async (
     addedScaledBalance,
     indexAfter,
   ]);
-  matchEvent(rcpt, 'Transfer', aToken, aToken.address, [
-    ZERO_ADDRESS,
-    user.address,
-    fromBalanceIncrease,
-  ]);
-  matchEvent(rcpt, 'Mint', aToken, aToken.address, [
-    user.address,
-    user.address,
-    fromBalanceIncrease,
-    fromBalanceIncrease,
-    indexAfter,
-  ]);
+  if (fromBalanceIncrease.gt(0)) {
+    matchEvent(rcpt, 'Transfer', aToken, aToken.address, [
+      ZERO_ADDRESS,
+      user.address,
+      fromBalanceIncrease,
+    ]);
+    matchEvent(rcpt, 'Mint', aToken, aToken.address, [
+      user.address,
+      user.address,
+      fromBalanceIncrease,
+      fromBalanceIncrease,
+      indexAfter,
+    ]);
+  }
   if (toBalanceIncrease.gt(0)) {
     matchEvent(rcpt, 'Transfer', aToken, aToken.address, [ZERO_ADDRESS, to, toBalanceIncrease]);
     matchEvent(rcpt, 'Mint', aToken, aToken.address, [
@@ -277,14 +279,20 @@ export const transferFrom = async (
     addedScaledBalance,
     indexAfter,
   ]);
-  matchEvent(rcpt, 'Transfer', aToken, aToken.address, [ZERO_ADDRESS, origin, fromBalanceIncrease]);
-  matchEvent(rcpt, 'Mint', aToken, aToken.address, [
-    user.address,
-    origin,
-    fromBalanceIncrease,
-    fromBalanceIncrease,
-    indexAfter,
-  ]);
+  if (fromBalanceIncrease.gt(0)) {
+    matchEvent(rcpt, 'Transfer', aToken, aToken.address, [
+      ZERO_ADDRESS,
+      origin,
+      fromBalanceIncrease,
+    ]);
+    matchEvent(rcpt, 'Mint', aToken, aToken.address, [
+      user.address,
+      origin,
+      fromBalanceIncrease,
+      fromBalanceIncrease,
+      indexAfter,
+    ]);
+  }
   if (toBalanceIncrease.gt(0)) {
     matchEvent(rcpt, 'Transfer', aToken, aToken.address, [ZERO_ADDRESS, to, toBalanceIncrease]);
     matchEvent(rcpt, 'Mint', aToken, aToken.address, [