bug(forge): warp effect is reversed when switching back to original fork

[anajuliabit]

Component

Forge

Have you ensured that all of these are up to date?

• Foundry
• Foundryup

What version of Foundry are you on?

forge 0.2.0 (6179312 2024-06-10T00:18:46.177980000Z)

What command(s) is the bug in?

forge script / forge test

Operating System

macOS (Apple Silicon)

Describe the bug

Scenario: two or more forks created using vm.createFork cheatcode
Bug: Use the warp cheatcode on fork 1 to move to a future timestamp, then switch to fork 2, and finally switch back to fork 1. The block.timestamp on fork 1 will be the block just before the warp.

Reproducing:

pragma solidity 0.8.19;

import {console} from "@forge-std/console.sol";
import {Script} from "@forge-std/Script.sol";

import "@forge-std/Test.sol";

contract MultipleForksWarp is Script, Test {
    /// @notice fork ID for moonbeam
    uint256 public moonbeamForkId =
        vm.createFork(vm.envString("MOONBEAM_RPC_URL"));

    /// @notice fork ID for base
    uint256 public baseForkId = vm.createFork(vm.envString("BASE_RPC_URL"));

    function run() public {
        console.log("Moonbeam fork selected");
        vm.selectFork(moonbeamForkId);
        console.log("Timestamp: ", block.timestamp);

        vm.warp(block.timestamp + 1000);
        console.log("Timestamp after warp: ", block.timestamp);

        console.log("Switching to base fork");
        vm.selectFork(baseForkId);

        console.log("Back to moonbeam fork");
        vm.selectFork(moonbeamForkId);

        console.log("Timestamp: ", block.timestamp);
    }
}

Script ran successfully.
Gas used: 36285

== Logs ==
  Moonbeam fork selected
  Timestamp:  1718386092
  Timestamp after warp:  1718387092
  Switching to base fork
  Back to moonbeam fork
  Timestamp:  1718386092

[grandizzy]

Can you please check if this happens also if you move initial forks creation / forks id recording in setUp function? (Or even directly in run)

[anajuliabit]

@grandizzy yes, it also happens

contract MultipleForksWarp is Script, Test {
    /// @notice fork ID for moonbeam
    uint256 public moonbeamForkId;

    /// @notice fork ID for base
    uint256 public baseForkId;

    function run() public {
        moonbeamForkId = vm.createFork(vm.envString("MOONBEAM_RPC_URL"));

        baseForkId = vm.createFork(vm.envString("BASE_RPC_URL"));

        console.log("Moonbeam fork selected");
        vm.selectFork(moonbeamForkId);
        console.log("Timestamp: ", block.timestamp);

        vm.warp(block.timestamp + 1000);
        console.log("Timestamp after warp: ", block.timestamp);

        console.log("Switching to base fork");
        vm.selectFork(baseForkId);

        console.log("Back to moonbeam fork");
        vm.selectFork(moonbeamForkId);

        console.log("Timestamp: ", block.timestamp);
    }
}

Script ran successfully
Gas used: 60478        
                       
== Logs ==             
Script ran successfully.
Gas used: 60478

== Logs ==
  Moonbeam fork selected
  Timestamp:  1718387790
  Timestamp after warp:  1718388790
  Switching to base fork
  Back to moonbeam fork
  Timestamp:  1718387790

[anajuliabit]

Hey, @grandizzy this still happens when you switch for the third time. The fix works only until the second switch