Revert "Revert "Merge pull request #329 from morpho-labs/fix/zero-tra…

…nsfer""

This reverts commit 1aa7ed8.

src/TransferBundler.sol

@@ -19,6 +19,7 @@ abstract contract TransferBundler is BaseBundler {
 
     /// @notice Transfers the minimum between the given `amount` and the bundler's balance of native asset from the
     /// bundler to `recipient`.
+    /// @dev If the minimum happens to be zero, the transfer is silently skipped.
     /// @param recipient The address that will receive the native tokens.
     /// @param amount The amount of native tokens to transfer from the initiator. Pass `type(uint256).max` to transfer
     /// the initiator's balance.
@@ -28,13 +29,14 @@ abstract contract TransferBundler is BaseBundler {
 
         amount = Math.min(amount, address(this).balance);
 
-        require(amount != 0, ErrorsLib.ZERO_AMOUNT);
+        if (amount == 0) return;
 
         SafeTransferLib.safeTransferETH(recipient, amount);
     }
 
     /// @notice Transfers the minimum between the given `amount` and the bundler's balance of `asset` from the bundler
     /// to `recipient`.
+    /// @dev If the minimum happens to be zero, the transfer is silently skipped.
     /// @param asset The address of the ERC20 token to transfer.
     /// @param recipient The address that will receive the tokens.
     /// @param amount The amount of `asset` to transfer. Pass `type(uint256).max` to transfer the bundler's balance.
@@ -44,7 +46,7 @@ abstract contract TransferBundler is BaseBundler {
 
         amount = Math.min(amount, ERC20(asset).balanceOf(address(this)));
 
-        require(amount != 0, ErrorsLib.ZERO_AMOUNT);
+        if (amount == 0) return;
 
         ERC20(asset).safeTransfer(recipient, amount);
     }

test/forge/TransferBundlerLocalTest.sol

@@ -15,7 +15,7 @@ contract TransferBundlerLocalTest is LocalTest {
     }
 
     function testTransfer(uint256 amount) public {
-        amount = bound(amount, MIN_AMOUNT, MAX_AMOUNT);
+        amount = bound(amount, 0, MAX_AMOUNT);
 
         bundle.push(_erc20Transfer(address(loanToken), RECEIVER, amount));
 
@@ -45,11 +45,17 @@ contract TransferBundlerLocalTest is LocalTest {
         bundler.multicall(bundle);
     }
 
-    function testTranferZeroAmount() public {
-        bundle.push(_erc20Transfer(address(loanToken), RECEIVER, 0));
+    function testNativeTransfer(uint256 amount) public {
+        amount = bound(amount, 0, MAX_AMOUNT);
+
+        bundle.push(_nativeTransfer(RECEIVER, amount));
+
+        deal(address(bundler), amount);
 
-        vm.expectRevert(bytes(ErrorsLib.ZERO_AMOUNT));
         bundler.multicall(bundle);
+
+        assertEq(address(bundler).balance, 0, "bundler.balance");
+        assertEq(RECEIVER.balance, amount, "RECEIVER.balance");
     }
 
     function testNativeTransferZeroAddress(uint256 amount) public {
@@ -70,13 +76,6 @@ contract TransferBundlerLocalTest is LocalTest {
         bundler.multicall(bundle);
     }
 
-    function testNativeTransferZeroAmount() public {
-        bundle.push(_nativeTransfer(RECEIVER, 0));
-
-        vm.expectRevert(bytes(ErrorsLib.ZERO_AMOUNT));
-        bundler.multicall(bundle);
-    }
-
     function testTransferFrom(uint256 amount) public {
         amount = bound(amount, MIN_AMOUNT, MAX_AMOUNT);