plonky2/evm/tests/basic_smart_contract.rs

use std::collections::HashMap;
use std::time::Duration;

use env_logger::{try_init_from_env, Env, DEFAULT_FILTER_ENV};
use eth_trie_utils::partial_trie::{Nibbles, PartialTrie};
use ethereum_types::{Address, U256};
use hex_literal::hex;
use keccak_hash::keccak;
use plonky2::field::goldilocks_field::GoldilocksField;
use plonky2::plonk::config::PoseidonGoldilocksConfig;
use plonky2::util::timing::TimingTree;
use plonky2_evm::all_stark::AllStark;
use plonky2_evm::config::StarkConfig;
use plonky2_evm::cpu::kernel::opcodes::{get_opcode, get_push_opcode};
use plonky2_evm::generation::mpt::AccountRlp;
use plonky2_evm::generation::{GenerationInputs, TrieInputs};
use plonky2_evm::proof::BlockMetadata;
use plonky2_evm::prover::prove;
use plonky2_evm::verifier::verify_proof;

type F = GoldilocksField;
const D: usize = 2;
type C = PoseidonGoldilocksConfig;

/// Test a simple token transfer to a new address.
#[test]
fn test_basic_smart_contract() -> anyhow::Result<()> {
    init_logger();

    let all_stark = AllStark::<F, D>::default();
    let config = StarkConfig::standard_fast_config();

    let beneficiary = hex!("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef");
    let sender = hex!("2c7536e3605d9c16a7a3d7b1898e529396a65c23");
    let to = hex!("a0a0a0a0a0a0a0a0a0a0a0a0a0a0a0a0a0a0a0a0");

    let beneficiary_state_key = keccak(beneficiary);
    let sender_state_key = keccak(sender);
    let to_state_key = keccak(to);

    let beneficiary_nibbles = Nibbles::from_bytes_be(beneficiary_state_key.as_bytes()).unwrap();
    let sender_nibbles = Nibbles::from_bytes_be(sender_state_key.as_bytes()).unwrap();
    let to_nibbles = Nibbles::from_bytes_be(to_state_key.as_bytes()).unwrap();

    let push1 = get_push_opcode(1);
    let add = get_opcode("ADD");
    let stop = get_opcode("STOP");
    let code = [push1, 3, push1, 4, add, stop];
    let code_gas = 3 + 3 + 3;
    let code_hash = keccak(code);

    let beneficiary_account_before = AccountRlp::default();
    let sender_account_before = AccountRlp {
        nonce: 5.into(),
        balance: eth_to_wei(100_000.into()),
        ..AccountRlp::default()
    };
    let to_account_before = AccountRlp {
        code_hash,
        ..AccountRlp::default()
    };

    let state_trie_before = {
        let mut children = core::array::from_fn(|_| PartialTrie::Empty.into());
        children[sender_nibbles.get_nibble(0) as usize] = PartialTrie::Leaf {
            nibbles: sender_nibbles.truncate_n_nibbles_front(1),
            value: rlp::encode(&sender_account_before).to_vec(),
        }
        .into();
        children[to_nibbles.get_nibble(0) as usize] = PartialTrie::Leaf {
            nibbles: to_nibbles.truncate_n_nibbles_front(1),
            value: rlp::encode(&to_account_before).to_vec(),
        }
        .into();
        PartialTrie::Branch {
            children,
            value: vec![],
        }
    };

    let tries_before = TrieInputs {
        state_trie: state_trie_before,
        transactions_trie: PartialTrie::Empty,
        receipts_trie: PartialTrie::Empty,
        storage_tries: vec![],
    };

    // Generated using a little py-evm script.
    let txn = hex!("f861050a8255f094a0a0a0a0a0a0a0a0a0a0a0a0a0a0a0a0a0a0a0a0648242421ba02c89eb757d9deeb1f5b3859a9d4d679951ef610ac47ad4608dc142beb1b7e313a05af7e9fbab825455d36c36c7f4cfcafbeafa9a77bdff936b52afb36d4fe4bcdd");
    let value = U256::from(100u32);

    let block_metadata = BlockMetadata {
        block_beneficiary: Address::from(beneficiary),
        ..BlockMetadata::default()
    };

    let mut contract_code = HashMap::new();
    contract_code.insert(code_hash, code.to_vec());
    let inputs = GenerationInputs {
        signed_txns: vec![txn.to_vec()],
        tries: tries_before,
        contract_code,
        block_metadata,
    };

    let mut timing = TimingTree::new("prove", log::Level::Debug);
    let proof = prove::<F, C, D>(&all_stark, &config, inputs, &mut timing)?;
    timing.filter(Duration::from_millis(100)).print();

    let expected_state_trie_after = {
        let txdata_gas = 2 * 16;
        let gas_used = 21_000 + code_gas + txdata_gas;

        let beneficiary_account_after = AccountRlp {
            balance: beneficiary_account_before.balance + gas_used * 10,
            ..beneficiary_account_before
        };
        let sender_account_after = AccountRlp {
            balance: sender_account_before.balance - value - gas_used * 10,
            nonce: sender_account_before.nonce + 1,
            ..sender_account_before
        };
        let to_account_after = AccountRlp {
            balance: to_account_before.balance + value,
            ..to_account_before
        };

        let mut children = core::array::from_fn(|_| PartialTrie::Empty.into());
        children[beneficiary_nibbles.get_nibble(0) as usize] = PartialTrie::Leaf {
            nibbles: beneficiary_nibbles.truncate_n_nibbles_front(1),
            value: rlp::encode(&beneficiary_account_after).to_vec(),
        }
        .into();
        children[sender_nibbles.get_nibble(0) as usize] = PartialTrie::Leaf {
            nibbles: sender_nibbles.truncate_n_nibbles_front(1),
            value: rlp::encode(&sender_account_after).to_vec(),
        }
        .into();
        children[to_nibbles.get_nibble(0) as usize] = PartialTrie::Leaf {
            nibbles: to_nibbles.truncate_n_nibbles_front(1),
            value: rlp::encode(&to_account_after).to_vec(),
        }
        .into();
        PartialTrie::Branch {
            children,
            value: vec![],
        }
    };

    assert_eq!(
        proof.public_values.trie_roots_after.state_root,
        expected_state_trie_after.calc_hash()
    );

    verify_proof(&all_stark, proof, &config)
}

fn eth_to_wei(eth: U256) -> U256 {
    // 1 ether = 10^18 wei.
    eth * U256::from(10).pow(18.into())
}

fn init_logger() {
    let _ = try_init_from_env(Env::default().filter_or(DEFAULT_FILTER_ENV, "info"));
}