feat(cheatcodes): include trace information about setting account code in EIP7702 transaction

[tinchoabbate]

Component

Forge

Describe the feature you would like

In a forge test that uses the vm.signAndAttachDelegation (or vm.attachDelegation) cheatcode, it'd be helpful if the test's trace somehow showed the account's code being set. Right now the process is opaque for the devs, and it's unclear whether the account's code was updated or not.

For example, right now if I do:

vm.signAndAttachDelegation(address(delegateContract), bob.privateKey);
address(0).call("");

Then the trace shows:

├─ [0] VM::signAndAttachDelegation(DelegateContractV1: [0x8Ad159a275AEE56fb2334DBb69036E9c7baCEe9b], 25733205992525344549959058604562080613152606839721263039386232180585134200482 [2.573e76])
│   └─ ← [Return] (1, 0x30326dccdd7ff594b3bfa85acdb7a472414233bcfef3db1a3aeaa453d10891b9, 0x76aee582915fbaf1cc3105cd7c1f37d4dbb13eaf64117fd9e6447fb50d281a2f, 0, 0x8Ad159a275AEE56fb2334DBb69036E9c7baCEe9b)
├─ [0] 0x0000000000000000000000000000000000000000::fallback()
│   └─ ← [Stop] 

But there's nothing in the call to address(0) that signals the call has 7702 data attached and that it's setting code to an account.

Additional context

No response

[zerosnacks]

Definitively in support of adding this, good idea

cc @evchip

[evchip]

Thanks @tinchoabbate, I'll look into this.

[evchip]

@tinchoabbate thanks for reporting this. You're right that the delegation code write isn't visible in traces because we currently write directly to state rather than executing through the EVM.

@zerosnacks I propose we modify attachDelegation and signAndAttachDelegation to simulate a type-4 EIP-7702 transaction (in addition to the current state write) specifically to generate proper traces. This would give visibility into the delegation process while maintaining current test behavior.

Happy to implement this if the approach sounds reasonable. Let me know if you'd prefer a different solution.

[evchip]

I’ve been working at this for a while but still haven’t been able to get set_code() to show up in the execution trace.

What I’ve tried so far:

• attachDelegation sets the account’s code inside the cheatcode execution, which happens outside the EVM execution trace.
• Attempted to inject a separate transaction inside ScriptRunner::simulate() to explicitly call set_code() before execution, but this happened outside the main transaction’s execution, so it never showed up in the trace.
• Tried modifying apply_cheatcode() to push a trace event manually, but that didn’t work and also felt like the wrong place to do it.

It seems like the best approach would be to push a new transaction into the stack when attachDelegation is executed, but i’m not sure what the cleanest way to do that is.

I would appreciate some direction cc @zerosnacks. Thanks