Contract

// SPDX-License-Identifier: MIT
pragma solidity 0.8.15;

import { Address } from "@openzeppelin/contracts/utils/Address.sol";

/**
 * @title Challenger1of2
 * @dev This contract serves the role of the Challenger, defined in L2OutputOracle.sol:
 * https://github.com/ethereum-optimism/optimism/blob/3580bf1b41d80fcb2b895d5610836bfad27fc989/packages/contracts-bedrock/contracts/L1/L2OutputOracle.sol
 * It enforces a simple 1 of 2 design, where neither party can remove the other's
 * permissions to execute a Challenger call.
 */
contract Challenger1of2 {
    using Address for address;

    /*//////////////////////////////////////////////////////////////
                            CONSTANTS
    //////////////////////////////////////////////////////////////*/
    /**
     * @dev The address of Optimism's signer (likely a multisig)
     */
    address public immutable OP_SIGNER;

    /**
     * @dev The address of counter party's signer (likely a multisig)
     */
    address public immutable OTHER_SIGNER;

    /**
     * @dev The address of the L2OutputOracleProxy contract.
     */
    address public immutable L2_OUTPUT_ORACLE_PROXY;

    /*//////////////////////////////////////////////////////////////
                            EVENTS
    //////////////////////////////////////////////////////////////*/
    /**
     * @dev Emitted when a Challenger call is made by a signer.
     * @param _caller The signer making the call.
     * @param _data The data of the call being made.
     * @param _result The result of the call being made.
     */
    event ChallengerCallExecuted(
        address indexed _caller,
        bytes _data,
        bytes _result
    );

    /*//////////////////////////////////////////////////////////////
                            Constructor
    //////////////////////////////////////////////////////////////*/
    /**
     * @dev Constructor to set the values of the constants.
     * @param _opSigner Address of Optimism signer.
     * @param _otherSigner Address of counter party signer.
     * @param _l2OutputOracleProxy Address of the L2OutputOracleProxy contract.
     */
    constructor(address _opSigner, address _otherSigner, address _l2OutputOracleProxy) {
        require(_opSigner != address(0), "Challenger1of2: opSigner cannot be zero address");
        require(_otherSigner != address(0), "Challenger1of2: otherSigner cannot be zero address");
        require(
            _l2OutputOracleProxy.isContract(),
            "Challenger1of2: l2OutputOracleProxy must be a contract"
        );

        OP_SIGNER = _opSigner;
        OTHER_SIGNER = _otherSigner;
        L2_OUTPUT_ORACLE_PROXY = _l2OutputOracleProxy;
    }

    /*//////////////////////////////////////////////////////////////
                        External Functions
    //////////////////////////////////////////////////////////////*/
    /**
     * @dev Executes a call as the Challenger (must be called by 
     * Optimism or counter party signer).
     * @param _data Data for function call.
     */
    function execute(bytes memory _data) external {
        require(
            msg.sender == OTHER_SIGNER || msg.sender == OP_SIGNER,
            "Challenger1of2: must be an approved signer to execute"
        );

        bytes memory result = Address.functionCall(
            L2_OUTPUT_ORACLE_PROXY,
            _data,
            "Challenger1of2: failed to execute"
        );

        emit ChallengerCallExecuted(msg.sender, _data, result);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly
                /// @solidity memory-safe-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

{
  "remappings": [
    "@base-contracts/=lib/base-contracts/",
    "@eth-optimism-bedrock/=lib/optimism/packages/contracts-bedrock/",
    "@openzeppelin/contracts-upgradeable/=lib/openzeppelin-contracts-upgradeable/contracts/",
    "@openzeppelin/contracts/=lib/openzeppelin-contracts/contracts/",
    "@rari-capital/solmate/=lib/solmate/",
    "base-contracts/=lib/base-contracts/src/",
    "ds-test/=lib/forge-std/lib/ds-test/src/",
    "forge-std/=lib/forge-std/src/",
    "optimism/=lib/optimism/",
    "solmate/=lib/solmate/src/"
  ],
  "optimizer": {
    "enabled": true,
    "runs": 999999
  },
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "outputSelection": {
    "*": {
      "*": [
        "evm.bytecode",
        "evm.deployedBytecode",
        "devdoc",
        "userdoc",
        "metadata",
        "abi"
      ]
    }
  },
  "evmVersion": "london",
  "libraries": {}
}

[{"inputs":[{"internalType":"address","name":"_opSigner","type":"address"},{"internalType":"address","name":"_otherSigner","type":"address"},{"internalType":"address","name":"_l2OutputOracleProxy","type":"address"}],"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"_caller","type":"address"},{"indexed":false,"internalType":"bytes","name":"_data","type":"bytes"},{"indexed":false,"internalType":"bytes","name":"_result","type":"bytes"}],"name":"ChallengerCallExecuted","type":"event"},{"inputs":[],"name":"L2_OUTPUT_ORACLE_PROXY","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"OP_SIGNER","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"OTHER_SIGNER","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"bytes","name":"_data","type":"bytes"}],"name":"execute","outputs":[],"stateMutability":"nonpayable","type":"function"}]

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0000000000000000000000004c35ca57616e0d5fd808574772f632d8da4eadca0000000000000000000000004574d0a407c9ef275128df822cf13bf8aef28bd80000000000000000000000002a35891ff30313ccfa6ce88dcf3858bb075a2298

-----Decoded View---------------
Arg [0] : _opSigner (address): 0x4C35Ca57616E0d5fD808574772f632D8dA4eadCa
Arg [1] : _otherSigner (address): 0x4574D0A407c9eF275128Df822CF13BF8aEF28BD8
Arg [2] : _l2OutputOracleProxy (address): 0x2A35891ff30313CcFa6CE88dcf3858bb075A2298

-----Encoded View---------------
3 Constructor Arguments found :
Arg [0] : 0000000000000000000000004c35ca57616e0d5fd808574772f632d8da4eadca
Arg [1] : 0000000000000000000000004574d0a407c9ef275128df822cf13bf8aef28bd8
Arg [2] : 0000000000000000000000002a35891ff30313ccfa6ce88dcf3858bb075a2298