fix(chain-1983): prevent initializing 0 token transfers (#106)

* fix(chain-1983): prevent initializing 0 token transfers

* chore: impl review feedback

Author: xenoliss

base/src/libraries/TokenLib.sol

@@ -55,6 +55,9 @@ library TokenLib {
     /// @notice Thrown when the token pair is not registered.
     error WrappedSplRouteNotRegistered();
 
+    /// @notice Thrown when the transfer amount is zero.
+    error ZeroAmount();
+
     //////////////////////////////////////////////////////////////
     ///                       Events                           ///
     //////////////////////////////////////////////////////////////
@@ -121,6 +124,8 @@ library TokenLib {
         internal
         returns (SolanaTokenType tokenType)
     {
+        require(transfer.remoteAmount > 0, ZeroAmount());
+
         TokenLibStorage storage $ = getTokenLibStorage();
         uint256 localAmount;
 
@@ -168,6 +173,8 @@ library TokenLib {
 
                 // Convert back to remote amount and transfer the dust back to the sender.
                 uint256 receivedRemoteAmount = receivedLocalAmount / scalar;
+                require(receivedRemoteAmount > 0, ZeroAmount());
+
                 localAmount = receivedRemoteAmount * scalar;
                 uint256 dust = receivedLocalAmount - localAmount;
                 if (dust > 0) {

base/test/libraries/TokenLib.t.sol

@@ -305,6 +305,19 @@ contract TokenLibTest is CommonTest {
         bridge.bridgeToken{value: 1 ether}(transfer, emptyIxs);
     }
 
+    function test_initializeTransfer_revertsOnZeroAmount() public {
+        Transfer memory transfer = Transfer({
+            localToken: address(mockToken),
+            remoteToken: TEST_REMOTE_TOKEN,
+            to: bytes32(uint256(uint160(alice))),
+            remoteAmount: 0
+        });
+
+        vm.expectRevert(TokenLib.ZeroAmount.selector);
+        Ix[] memory emptyIxs;
+        bridge.bridgeToken(transfer, emptyIxs);
+    }
+
     //////////////////////////////////////////////////////////////
     ///               Finalize Transfer Tests                  ///
     //////////////////////////////////////////////////////////////