cleanup multisig builder

src/templates/MultisigBuilder.sol

@@ -1,34 +1,48 @@
 // SPDX-License-Identifier: BUSL-1.1
 pragma solidity ^0.8.12;
 
-import {ZeusScript} from "../utils/ZeusScript.sol";
+import "../utils/ZeusScript.sol";
 
 /**
  * @title MultisigBuilder
  * @dev Abstract contract for building arbitrary multisig scripts.
  */
 abstract contract MultisigBuilder is ZeusScript {
+
+    bool private hasPranked;
+
+    modifier prank(address caller) {
+        _startPrank(caller);
+        _;
+        _stopPrank();
+    }
+
     /**
      * @notice Constructs a SafeTx object for a Gnosis Safe to ingest. Emits via `ZeusMultisigExecute`
      */
     function execute() public {
-        MultisigOptions memory opt = options();
-        emit ZeusRequireMultisig(opt.addr, opt.callType);
-        vm.startPrank(opt.addr, opt.addr);
-        runAsMultisig();
-        vm.stopPrank();
+        _runAsMultisig();
+        require(hasPranked, "MultisigBuilder.execute: did not use prank helpers");
     }
 
     /**
-     * Indicate the multisig address
+     * @dev Implement the most high-level call performed by the target multisig for this script.
+     * Note: This function should be written as if the target multisig is performing the call directly.
+     * Note: This function MUST be written by using the `prank` modifier or `_startPrank`/`_stopPrank`
+     * helper methods.
      */
-    function options() internal virtual returns (MultisigOptions memory);
+    function _runAsMultisig() internal virtual;
 
-    /**
-     * @notice To be implemented by inheriting contract.
-     *
-     * This function will be pranked from the perspective of the multisig you choose to run with.
-     * DO NOT USE vm.startPrank()/stopPrank() during your implementation.
-     */
-    function runAsMultisig() internal virtual;
+    function _startPrank(address caller) internal {
+        require(!hasPranked, "MultisigBuilder._startPrank: called twice in txn");
+        hasPranked = true;
+
+        emit ZeusRequireMultisig(caller, Encode.Operation.Call);
+        vm.startPrank(caller);
+    }
+
+    function _stopPrank() internal {
+        require(hasPranked, "MultisigBuilder._stopPrank: _startPrank not called");
+        vm.stopPrank();
+    }
 }

src/utils/ZeusScript.sol

@@ -12,17 +12,12 @@ abstract contract ZeusScript is Script, Test {
     using StringUtils for string;
     using ZEnvHelpers for *;
 
-    enum Operation {
-        Call,
-        DelegateCall
-    }
-
     struct MultisigOptions {
         address addr; // the address of the multisig
-        Operation callType; // call vs. delegateCall
+        Encode.Operation callType; // call vs. delegateCall
     }
 
-    event ZeusRequireMultisig(address addr, Operation callType);
+    event ZeusRequireMultisig(address addr, Encode.Operation callType);
     event ZeusEnvironmentUpdate(string key, EnvironmentVariableType internalType, bytes value);
     event ZeusDeploy(string name, address addr, bool singleton);
     event ZeusMultisigExecute(address to, uint256 value, bytes data, Encode.Operation op);

test/ZeusScript.test.sol

@@ -404,9 +404,8 @@ contract ZeusScriptTest is EOADeployer {
 
     function testZeusRequireMultisigEvent() public {
         vm.expectEmit(true, true, true, true);
-        emit ZeusRequireMultisig(address(0xabc), Operation.Call);
-        // Operation.Call and Operation.DelegateCall are from the enum defined in ZeusScript
-        emit ZeusRequireMultisig(address(0xabc), Operation.Call);
+        emit ZeusRequireMultisig(address(0xabc), Encode.Operation.Call);
+        emit ZeusRequireMultisig(address(0xabc), Encode.Operation.Call);
     }
 
     function testZeusDeployEvent() public {
@@ -519,8 +518,8 @@ contract ZeusScriptTest is EOADeployer {
     function testZeusRequireMultisigEventDelegateCall() public {
         // Emit with DelegateCall to cover enum branch
         vm.expectEmit(true, true, true, true);
-        emit ZeusRequireMultisig(address(0xabc), Operation.DelegateCall);
-        emit ZeusRequireMultisig(address(0xabc), Operation.DelegateCall);
+        emit ZeusRequireMultisig(address(0xabc), Encode.Operation.DelegateCall);
+        emit ZeusRequireMultisig(address(0xabc), Encode.Operation.DelegateCall);
     }
 
     function testZeusDeployEventFalseSingleton() public {