Bring-up of state trie hash verification function

[shamb0]

Bring-up of state trie hash verification function.

Observing mismatch in hash value under FEVM context.

Summary

Modified test vector with single transaction, common test vector used in both fevm & revm context.

• mod-push0.json

Mismatch in computed state trie hash value under FEVM context

• Complete Trace

Computed state trie hash value under revm context

• Complete Trace

Difference in state properties values, used for calculating state trie hash.

Mismatch in bytecode hash

FEVM context

revm context

Mismatch in slot status @0000000000000000000000000000000000000400

FEVM context

revm context

[shamb0]

CC @Stebalien, @vyzo

[Stebalien]

For the first case, can you print out the state trees from both cases? I.e., the slots so I can see where the difference is?

[Stebalien]

Ah... there aren't separate sub tests.

[Stebalien]

But yes, this is exactly what we're looking for.

One thing that's confusing me is that both FEVM and REVM agree on the state of b94f5374fce5edbc8e2a8697c15331677e6ebf0b, but the tests don't.

[Stebalien]

But I solved the bytecode hash issue.

fevm-eth-compliance-test/src/common/tester.rs

Lines 384 to 410 in 53648dc

	fn init_fevm(&mut self, code: Bytes, nonce: u64, kamt_config: KamtConfig) -> Result<Cid> {
	let state_tree = self.executor.as_mut().unwrap().state_tree_mut();
	let hasher = Code::try_from(SupportedHashes::Keccak256 as u64).unwrap();
	let code_hash = multihash::Multihash::wrap(
	SupportedHashes::Keccak256 as u64,
	&hasher.digest(&code).to_bytes(),
	)
	.expect("failed to hash bytecode with keccak");
	let code_cid = state_tree
	.store()
	.put(Code::Blake2b256, &Block::new(IPLD_RAW, code))
	.expect("failed to write bytecode");
	let mut slots = StateKamt::new_with_config(state_tree.store(), kamt_config);
	let evm_state = EvmState {
	bytecode: code_cid,
	bytecode_hash: BytecodeHash::try_from(&code_hash.to_bytes()[..32]).unwrap(),
	contract_state: slots.flush().expect("failed to flush contract state"),
	nonce,
	tombstone: None,
	};
	state_tree.store().put_cbor(&evm_state, Code::Blake2b256)
	}

The bytecodehash as stored in the state is the hash digest, not a multihash. I.e., there's no need to wrap the hash digest in a multihahs, convert it to bytes, then take the first 32. Just take the entire digest:

fevm-eth-compliance-test/src/common/tester.rs

Line 390 in 53648dc

&hasher.digest(&code).to_bytes(),

If possible, I recommend that you use the EVM's builtin constructor.

[Stebalien]

#4

[Stebalien]

Mismatch in slot status @0000000000000000000000000000000000000400

It looks like you aren't inserting the slots from the "pre" section before running the test.

[shamb0]

Hello @Stebalien,

Update-01 :: Quick fix to suppress the error ExitCode::SYS_SENDER_INVALID | "Send not from valid sender"

• Based on state of the condition flag, error "Send not from valid sender" is due to is_placeholder_actor() is not set.

• Indeed state of is_placeholder_actor() not set is valid, since fevm actor is created during runtime & it's not part of the manifest file.

• As a quick hack, Re-factored the logic as below to suppress the error. Could you please kindly suggest the better alternate to handle this.

https://github.com/shamb0/ref-fvm/blob/shamb0/mirror-master/fvm/src/executor/default.rs#L422

[shamb0]

Update-02 :: Status on analysis of mismatch in state trie hash calculated value.

Here are some observation on the properties of ActorState for the address
0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b

• Observation-01 :: Difference in gas_used between revm & fevm

prop	fevm	revm
base_fee	0.00000000000000001	TODO
initial_balance	17592186044416	17592186044416
balance_after_transaction	17592186044416	17592184564106
balance_diff	0	1480310
gas_used	4367801	148031

from the traces, looks like ActorState::deduct_funds() is always passed with value zero, Can I have some clarity on this behavior ?

• Observation-02 :: Please correct me if I'm wrong, Looks like functionality of the property ActorState::sequence & fil_actor_evm::State::nonce are duplicates, but the values are in out-of sync.

[Stebalien]

Send not from valid sender

You need to send messages from an account or placeholder, not an EVM actor. The EVM doesn't distinguish between accounts and contracts, but we do.

To handle this, you likely need to check AccountInfo::code. If code is empty, create an account actor here:

fevm-eth-compliance-test/src/statetest/executor.rs

Line 441 in 3d9c693

let evm_code_cid = self.tester.code_by_id(ActorType::EVM as u32).unwrap();

If it's non-empty, create an EVM actor as usual.

[Stebalien]

from the traces, looks like ActorState::deduct_funds() is always passed with value zero, Can I have some clarity on this behavior ?

I'm not sure where you're getting those traces, I assume you've modified something?

I'm guessing that you're setting the base-fee to 0. In which case yes, we'll charge nothing for gas.

Observation-02 :: Please correct me if I'm wrong, Looks like functionality of the property ActorState::sequence & fil_actor_evm::State::nonce are duplicates, but the values are in out-of sync.

That's a bit tricky:

1. ActorState::sequence is the Filecoin nonce and is only used by accounts to order off-chain messages.
2. fil_actor_evm::State::nonce is the EVM nonce and is used in CREATE to derive the address.

fil_actor_evm::State::nonce exists because the EVM needs to update this nonce every time it creates a new contract, but actors aren't allowed to manually increment their Filecoin nonce (ActorState::sequence).

Short version: For accounts (ethereum-style accounts and native accounts), always look at ActorState::sequence. For everything else, ignore it.

[shamb0]

To handle this, you likely need to check AccountInfo::code. If code is empty, create an account actor here:

fevm-eth-compliance-test/src/statetest/executor.rs

Line 441 in 3d9c693

let evm_code_cid = self.tester.code_by_id(ActorType::EVM as u32).unwrap();

If it's non-empty, create an EVM actor as usual.

Looks like I'm missing some information piece, in managing place-holder address & fevm actor address. Could you please kindly review the latest integration ?

https://github.dev/shamb0/fevm-eth-compliance-test/blob/shamb0/verify-merkle-trie/src/statetest/executor.rs#L406

[shamb0]

I'm guessing that you're setting the base-fee to 0. In which case yes, we'll charge nothing for gas.

Using the base-fee value from the test vector property. Can we use it straight or any transformation required ?

https://github.com/shamb0/fevm-eth-compliance-test-trace/blob/b333f5adef012b83ef287ded0bc4de1a8c77eafc/GeneralStateTests/EIPTests/stEIP3855/TID-01-04-01-mod-push0.json#LL22C2-L22C2

[Stebalien]

Looks like I'm missing some information piece, in managing place-holder address & fevm actor address. Could you please kindly review the latest integration ?

• If info.code is empty, construct an EthAccount https://github.com/filecoin-project/builtin-actors/blob/89dc63dfc9473d7db42525bf59bb0e679d8c9c41/actors/ethaccount/src/lib.rs. Specifically, create an actor with empty state (EMPTY_ARR_CID) and with the EthAccount code CID (e.g., https://github.com/filecoin-project/ref-fvm/blob/456ab0d9783f4d486848af811c87d7a6bccb35e3/fvm/src/executor/default.rs#L427).
• Otherwise, create an EVM actor as usual.

[Stebalien]

Using the base-fee value from the test vector property. Can we use it straight or any transformation required ?

What are you trying to test? The gas used by FEVM will always differ from the gas used by the EVM.

[shamb0]

Using the base-fee value from the test vector property. Can we use it straight or any transformation required ?

What are you trying to test? The gas used by FEVM will always differ from the gas used by the EVM.

Oops, then we can't use the state root hash to test against the post::testcase::hash, which is part of the test vector.

Computation of state root hash, has dependency on state of contract balance. (After executing the transaction use-cases, gas_used is
deducted from the contract account balance).