♻️ Make admin functions return true

README.md

@@ -2,7 +2,22 @@
 
 A barebones implementation of a gasback contract that implements [RIP-7767](https://github.com/ethereum/RIPs/blob/master/RIPS/rip-7767.md).
 
-## Suggested deployment for OP stack chains
+## Suggested setup for OP stack chains
+
+### Requirements
+
+- The `baseFeeVault` is deployed at `0x4200000000000000000000000000000000000019`.
+- The `WITHDRAWAL_NETWORK` of the `baseFeeVault` is set to `1`.
+
+### Via script
+
+See `script/Delegate7702.s.sol` for an automated script that can help you deploy.
+
+This script requires you to have the private key of the `baseFeeVault` recipient in your environment.
+
+For more information on how to run a foundry script, see `https://getfoundry.sh/guides/scripting-with-solidity`.
+
+### Manual steps
 
 1. Deploy the `gasback` contract which will be used as an implementation via EIP-7702.
 
@@ -13,7 +28,7 @@ A barebones implementation of a gasback contract that implements [RIP-7767](http
      `900000000000000000`
    - `setGasbackMaxBaseFee(uint256)`  
      `115792089237316195423570985008687907853269984665640564039457584007913129639935`  
-   - `setBaseFeeVault(address)`  
+   - `setbaseFeeVault(address)`  
      `0x4200000000000000000000000000000000000019`
 
 4. Put or leave some ETH into the EOA `RECIPIENT`, which will be the actual `gasback` contract. 

script/Delegate7702.s.sol

@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.4;
+
+import {Script} from "forge-std/Script.sol";
+import "../src/Gasback.sol";
+
+contract Delegate7702Script is Script {
+    function run() external {
+        uint256 privateKey = uint256(vm.envBytes32("PRIVATE_KEY"));
+
+        address gasbackImplementation = _deployWithNicks(type(Gasback).creationCode);
+        address deployer = vm.addr(privateKey);
+
+        vm.signAndAttachDelegation(gasbackImplementation, privateKey);
+        bytes memory code = deployer.code;
+        require(code.length > 0, "Not delegation detected");
+
+        vm.startBroadcast(privateKey);
+        Gasback(payable(deployer)).setGasbackRatioNumerator(900000000000000000);
+        vm.stopBroadcast();
+
+        vm.startBroadcast(privateKey);
+        Gasback(payable(deployer)).setGasbackMaxBaseFee(type(uint256).max);
+        vm.stopBroadcast();
+
+        vm.startBroadcast(privateKey);
+        Gasback(payable(deployer)).setBaseFeeVault(0x4200000000000000000000000000000000000019);
+        vm.stopBroadcast();
+    }
+
+    /// @dev Returns the address deployed via Nick's factory with salt `bytes32(0)`.
+    /// If the contract has already been deployed, skips deploying it.
+    function _deployWithNicks(bytes memory code) internal returns (address) {
+        address nicks = 0x4e59b44847b379578588920cA78FbF26c0B4956C;
+        address instance = _predictDeterministicAddress(keccak256(code), 0, nicks);
+        if (instance.code.length != 0) return instance;
+        (bool success,) = nicks.call(abi.encodePacked(bytes32(0), code));
+        require(success && instance.code.length != 0, "Deployment via Nick's failed.");
+        return instance;
+    }
+
+    /// @dev Returns the address when a contract with initialization code hash,
+    /// `hash`, is deployed with `salt`, by `deployer`.
+    /// Note: The returned result has dirty upper 96 bits. Please clean if used in assembly.
+    function _predictDeterministicAddress(bytes32 hash, bytes32 salt, address deployer)
+        internal
+        pure
+        returns (address predicted)
+    {
+        /// @solidity memory-safe-assembly
+        assembly {
+            // Compute and store the bytecode hash.
+            mstore8(0x00, 0xff) // Write the prefix.
+            mstore(0x35, hash)
+            mstore(0x01, shl(96, deployer))
+            mstore(0x15, salt)
+            predicted := keccak256(0x00, 0x55)
+            mstore(0x35, 0) // Restore the overwritten part of the free memory pointer.
+        }
+    }
+}

src/Gasback.sol

@@ -77,27 +77,31 @@ contract Gasback {
     /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/
 
     /// @dev Withdraws ETH from this contract.
-    function withdraw(address to, uint256 amount) public onlySystemOrThis {
+    function withdraw(address to, uint256 amount) public onlySystemOrThis returns (bool) {
         /// @solidity memory-safe-assembly
         assembly {
             if iszero(call(gas(), to, amount, 0x00, 0x00, 0x00, 0x00)) { revert(0x00, 0x00) }
         }
+        return true;
     }
 
     /// @dev Sets the numerator for the gasback ratio.
-    function setGasbackRatioNumerator(uint256 value) public onlySystemOrThis {
+    function setGasbackRatioNumerator(uint256 value) public onlySystemOrThis returns (bool) {
         require(value <= GASBACK_RATIO_DENOMINATOR);
         _getGasbackStorage().gasbackRatioNumerator = value;
+        return true;
     }
 
     /// @dev Sets the max base fee.
-    function setGasbackMaxBaseFee(uint256 value) public onlySystemOrThis {
+    function setGasbackMaxBaseFee(uint256 value) public onlySystemOrThis returns (bool) {
         _getGasbackStorage().gasbackMaxBaseFee = value;
+        return true;
     }
 
     /// @dev Sets the base fee vault.
-    function setBaseFeeVault(address value) public onlySystemOrThis {
+    function setBaseFeeVault(address value) public onlySystemOrThis returns (bool) {
         _getGasbackStorage().baseFeeVault = value;
+        return true;
     }
 
     /// @dev Guards the function such that it can only be called either by