Ability to mine/wait for blocks in scripts

[naps62]

Component

Forge

Describe the feature you would like

This is a follow-up on #1848 , which got closed even thought the bug (rust panic) still persists

In scripts, we can use --slow to force transactions to happen across different blocks. However, if those transactions rely on data such as blockhash(block.number - 1), forge will actually fail to simulate them, because no actual blocks and blockhashes are being created during that time. e.g., the following fails in a script, but works in a unit test:

        for (uint256 i = 0; i < 10; ++i) {
           vm.broadcast();
           submitTransaction();
            vm.roll(block.number + 1); // need to roll because `submitTransaction` didn't actually create a new block
            console.logBytes32(blockhash(block.number - 1));
        }

The specific error I get is :

Message:  Failed to get block hash for 10826800
block 10826800 not found

It would be very useful to be able to request our forked instance (anvil?) to simulate a new block being mined, which is the behaviour necessary here, and what suposedly --slow should enforce

Additional context

My real-world scenario here is actually trying to solve Ethernaut #03 on-chain using a forge script.
The script must:

• deploy the ethernaut level instance
• solve it, which requires submitting 10 different transactions across 10 different blocks

The current blocker for this is that each call relies on blockhash(block.number - 1), which doesn't seem to exist while simulating the script

[onbjerg]

Marking this as hard because I think it will be - feel free to correct @joshieDo

[foufrix]

Hi, @naps62 did you manage to make it work with a while loop? I'm having exactly the same issue as you and launched it 10 times by hand to solve that, I'm pretty sure there could be a cleaner way to do that.

EDIT: actually working for testing locally, but not possible when using a script on testnet