chore(claim): move state update before call (#1645)

Co-authored-by: Javier Rodríguez Chatruc <[email protected]>
Co-authored-by: Julian Arce <[email protected]>

Author: 3 people

claim_contracts/src/ClaimableAirdrop.sol

@@ -112,6 +112,9 @@ contract ClaimableAirdrop is
 
         require(verifies, "Invalid Merkle proof");
 
+        // Done before the transfer call to make sure the reentrancy bug is not possible
+        hasClaimed[msg.sender] = true;
+
         bool success = IERC20(tokenProxy).transferFrom(
             tokenDistributor,
             msg.sender,
@@ -120,8 +123,6 @@ contract ClaimableAirdrop is
 
         require(success, "Failed to transfer funds");
 
-        hasClaimed[msg.sender] = true;
-
         emit TokensClaimed(msg.sender, amount);
     }