Make InputBox require application contract deployment

Author: guidanoli

.changeset/angry-worms-dig.md

@@ -0,0 +1,5 @@
+---
+"@cartesi/rollups": major
+---
+
+Make `InputBox` require application contract deployment

src/inputs/IInputBox.sol

@@ -22,6 +22,10 @@ interface IInputBox {
     /// @param input The input
     event InputAdded(address indexed appContract, uint256 indexed index, bytes input);
 
+    /// @notice The application contract was not deployed yet.
+    /// @param appContract The application contract address
+    error ApplicationContractNotDeployed(address appContract);
+
     /// @notice Input is too large.
     /// @param appContract The application contract address
     /// @param inputLength The input length

src/inputs/InputBox.sol

@@ -1,17 +1,19 @@
 // (c) Cartesi and individual authors (see AUTHORS)
 // SPDX-License-Identifier: Apache-2.0 (see LICENSE)
 
-pragma solidity ^0.8.18;
+pragma solidity ^0.8.27;
 
 import {IInputBox} from "./IInputBox.sol";
 import {CanonicalMachine} from "../common/CanonicalMachine.sol";
 import {Inputs} from "../common/Inputs.sol";
 import {LibBinaryMerkleTree} from "../library/LibBinaryMerkleTree.sol";
 import {LibKeccak256} from "../library/LibKeccak256.sol";
 import {LibMath} from "../library/LibMath.sol";
+import {LibAddress} from "../library/LibAddress.sol";
 
 contract InputBox is IInputBox {
     using LibMath for uint256;
+    using LibAddress for address;
     using LibBinaryMerkleTree for bytes;
 
     /// @notice Deployment block number
@@ -26,6 +28,8 @@ contract InputBox is IInputBox {
         override
         returns (bytes32)
     {
+        require(appContract.hasCode(), ApplicationContractNotDeployed(appContract));
+
         bytes32[] storage inputBox = _inputBoxes[appContract];
 
         uint256 index = inputBox.length;

src/library/LibAddress.sol

@@ -52,4 +52,11 @@ library LibAddress {
             returndata.raise();
         }
     }
+
+    /// @notice Check whether an account has any code.
+    /// @param account The account address
+    /// @return Whether the account has any code.
+    function hasCode(address account) internal view returns (bool) {
+        return account.code.length > 0;
+    }
 }

test/inputs/InputBox.t.sol

@@ -4,6 +4,9 @@
 pragma solidity ^0.8.22;
 
 import {Test} from "forge-std-1.9.6/src/Test.sol";
+
+import {Create2} from "@openzeppelin-contracts-5.2.0/utils/Create2.sol";
+
 import {InputBox} from "src/inputs/InputBox.sol";
 import {IInputBox} from "src/inputs/IInputBox.sol";
 import {CanonicalMachine} from "src/common/CanonicalMachine.sol";
@@ -14,6 +17,8 @@ import {LibMath} from "src/library/LibMath.sol";
 
 import {EvmAdvanceEncoder} from "../util/EvmAdvanceEncoder.sol";
 
+contract MockApplication {}
+
 contract InputBoxTest is Test {
     using LibMath for uint256;
     using LibBinaryMerkleTree for bytes;
@@ -34,8 +39,27 @@ contract InputBoxTest is Test {
         assertEq(_inputBox.getNumberOfInputs(appContract), 0);
     }
 
+    function testAddInputNoContract(
+        uint256 privateKey,
+        bytes32 salt,
+        bytes calldata payload
+    ) external {
+        privateKey = boundPrivateKey(privateKey);
+
+        _testAddInputNoContract(address(0), payload);
+        _testAddInputNoContract(vm.addr(privateKey), payload);
+
+        bytes32 bytecodeHash = keccak256(type(MockApplication).creationCode);
+        address appContract = Create2.computeAddress(salt, bytecodeHash);
+        _testAddInputNoContract(appContract, payload);
+
+        assertEq(appContract, address(new MockApplication{salt: salt}()));
+        assertGt(appContract.code.length, 0);
+        _inputBox.addInput(appContract, payload);
+    }
+
     function testAddLargeInput() public {
-        address appContract = vm.addr(1);
+        address appContract = address(new MockApplication());
         uint256 max = _getMaxInputPayloadLength();
 
         _inputBox.addInput(appContract, new bytes(max));
@@ -55,9 +79,9 @@ contract InputBoxTest is Test {
         _inputBox.addInput(appContract, largePayload);
     }
 
-    function testAddInput(uint64 chainId, address appContract, bytes[] calldata payloads)
-        public
-    {
+    function testAddInput(uint64 chainId, bytes[] calldata payloads) public {
+        address appContract = address(new MockApplication());
+
         vm.chainId(chainId); // foundry limits chain id to be less than 2^64 - 1
 
         uint256 numPayloads = payloads.length;
@@ -120,6 +144,18 @@ contract InputBoxTest is Test {
         }
     }
 
+    function _testAddInputNoContract(address appContract, bytes calldata payload)
+        internal
+    {
+        assertEq(appContract.code.length, 0, "expected account with no code");
+        vm.expectRevert(
+            abi.encodeWithSelector(
+                IInputBox.ApplicationContractNotDeployed.selector, appContract
+            )
+        );
+        _inputBox.addInput(appContract, payload);
+    }
+
     function _prevrandao(uint256 blockNumber) internal pure returns (uint256) {
         return uint256(keccak256(abi.encode("prevrandao", blockNumber)));
     }