reth_rpc/eth/

sim_bundle.rs

//! `Eth` Sim bundle implementation and helpers.

use alloy_consensus::{transaction::TxHashRef, BlockHeader};
use alloy_eips::BlockNumberOrTag;
use alloy_evm::{env::BlockEnvironment, overrides::apply_block_overrides};
use alloy_primitives::U256;
use alloy_rpc_types_eth::{BlockId, Log};
use alloy_rpc_types_mev::{
    BundleItem, Inclusion, MevSendBundle, Privacy, RefundConfig, SimBundleLogs, SimBundleOverrides,
    SimBundleResponse, Validity,
};
use jsonrpsee::core::RpcResult;
use reth_evm::{ConfigureEvm, Evm};
use reth_primitives_traits::Recovered;
use reth_rpc_api::MevSimApiServer;
use reth_rpc_eth_api::{
    helpers::{block::LoadBlock, Call, EthTransactions},
    FromEthApiError, FromEvmError,
};
use reth_rpc_eth_types::{utils::recover_raw_transaction, EthApiError};
use reth_storage_api::ProviderTx;
use reth_tasks::pool::BlockingTaskGuard;
use reth_transaction_pool::{PoolPooledTx, PoolTransaction, TransactionPool};
use revm::{
    context::Block, context_interface::result::ResultAndState, DatabaseCommit, DatabaseRef,
};
use std::{sync::Arc, time::Duration};
use tracing::trace;

/// Maximum bundle depth
const MAX_NESTED_BUNDLE_DEPTH: usize = 5;

/// Maximum body size
const MAX_BUNDLE_BODY_SIZE: usize = 50;

/// Default simulation timeout
const DEFAULT_SIM_TIMEOUT: Duration = Duration::from_secs(5);

/// Maximum simulation timeout
const MAX_SIM_TIMEOUT: Duration = Duration::from_secs(30);

/// Maximum payout cost
const SBUNDLE_PAYOUT_MAX_COST: u64 = 30_000;

/// A flattened representation of a bundle item containing transaction and associated metadata.
#[derive(Clone, Debug)]
pub struct FlattenedBundleItem<T> {
    /// The signed transaction
    pub tx: Recovered<T>,
    /// Whether the transaction is allowed to revert
    pub can_revert: bool,
    /// Item-level inclusion constraints
    pub inclusion: Inclusion,
    /// Optional validity constraints for the bundle item
    pub validity: Option<Validity>,
    /// Optional privacy settings for the bundle item
    pub privacy: Option<Privacy>,
    /// Optional refund percent for the bundle item
    pub refund_percent: Option<u64>,
    /// Optional refund configs for the bundle item
    pub refund_configs: Option<Vec<RefundConfig>>,
}

/// `Eth` sim bundle implementation.
pub struct EthSimBundle<Eth> {
    /// All nested fields bundled together.
    inner: Arc<EthSimBundleInner<Eth>>,
}

impl<Eth> EthSimBundle<Eth> {
    /// Create a new `EthSimBundle` instance.
    pub fn new(eth_api: Eth, blocking_task_guard: BlockingTaskGuard) -> Self {
        Self { inner: Arc::new(EthSimBundleInner { eth_api, blocking_task_guard }) }
    }

    /// Access the underlying `Eth` API.
    pub fn eth_api(&self) -> &Eth {
        &self.inner.eth_api
    }

    /// Builds a hierarchical `SimBundleLogs` structure from flattened transaction logs.
    fn build_bundle_logs(
        bundle: &MevSendBundle,
        flat_logs: &[Vec<Log>],
    ) -> Result<Vec<SimBundleLogs>, EthApiError> {
        struct BundleFrame<'a> {
            bundle: &'a MevSendBundle,
            next_idx: usize,
            logs: Vec<SimBundleLogs>,
        }

        let mut stack = vec![BundleFrame { bundle, next_idx: 0, logs: Vec::new() }];
        let mut flat_log_idx = 0;
        let mut root_logs = None;

        while let Some(mut frame) = stack.pop() {
            if frame.next_idx == frame.bundle.bundle_body.len() {
                if let Some(parent) = stack.last_mut() {
                    parent
                        .logs
                        .push(SimBundleLogs { tx_logs: None, bundle_logs: Some(frame.logs) });
                } else {
                    root_logs = Some(frame.logs);
                }

                continue;
            }

            match &frame.bundle.bundle_body[frame.next_idx] {
                BundleItem::Tx { .. } => {
                    let tx_logs = flat_logs.get(flat_log_idx).cloned().ok_or_else(|| {
                        EthApiError::InvalidParams(EthSimBundleError::UnmatchedBundle.to_string())
                    })?;

                    frame.logs.push(SimBundleLogs { tx_logs: Some(tx_logs), bundle_logs: None });
                    frame.next_idx += 1;
                    flat_log_idx += 1;
                    stack.push(frame);
                }
                BundleItem::Bundle { bundle } => {
                    frame.next_idx += 1;
                    stack.push(frame);
                    stack.push(BundleFrame { bundle, next_idx: 0, logs: Vec::new() });
                }
                BundleItem::Hash { .. } => {
                    return Err(EthApiError::InvalidParams(
                        EthSimBundleError::InvalidBundle.to_string(),
                    ));
                }
            }
        }

        if flat_log_idx != flat_logs.len() {
            return Err(EthApiError::InvalidParams(EthSimBundleError::UnmatchedBundle.to_string()));
        }

        root_logs.ok_or_else(|| {
            EthApiError::InvalidParams(EthSimBundleError::UnmatchedBundle.to_string())
        })
    }
}

impl<Eth> EthSimBundle<Eth>
where
    Eth: EthTransactions + LoadBlock + Call + 'static,
{
    /// Flattens a potentially nested bundle into a list of individual transactions in a
    /// `FlattenedBundleItem` with their associated metadata. This handles recursive bundle
    /// processing up to `MAX_NESTED_BUNDLE_DEPTH` and `MAX_BUNDLE_BODY_SIZE`, preserving
    /// inclusion, validity and privacy settings from parent bundles.
    fn parse_and_flatten_bundle(
        &self,
        request: &MevSendBundle,
    ) -> Result<Vec<FlattenedBundleItem<ProviderTx<Eth::Provider>>>, EthApiError> {
        let mut items = Vec::new();

        // Stack for processing bundles
        let mut stack = Vec::new();

        // Start with initial bundle, index 0, and depth 1
        stack.push((request, 0, 1));

        while let Some((current_bundle, mut idx, depth)) = stack.pop() {
            // Check max depth
            if depth > MAX_NESTED_BUNDLE_DEPTH {
                return Err(EthApiError::InvalidParams(EthSimBundleError::MaxDepth.to_string()));
            }

            // Determine inclusion, validity, and privacy
            let inclusion = &current_bundle.inclusion;
            let validity = &current_bundle.validity;
            let privacy = &current_bundle.privacy;

            // Validate inclusion parameters
            let block_number = inclusion.block_number();
            let max_block_number = inclusion.max_block_number().unwrap_or(block_number);

            if max_block_number < block_number || block_number == 0 {
                return Err(EthApiError::InvalidParams(
                    EthSimBundleError::InvalidInclusion.to_string(),
                ));
            }

            // Validate bundle body size
            if current_bundle.bundle_body.len() > MAX_BUNDLE_BODY_SIZE {
                return Err(EthApiError::InvalidParams(
                    EthSimBundleError::BundleTooLarge.to_string(),
                ));
            }

            // Validate validity and refund config
            if let Some(validity) = &current_bundle.validity {
                // Validate refund entries
                if let Some(refunds) = &validity.refund {
                    let mut total_percent = 0;
                    for refund in refunds {
                        if refund.body_idx as usize >= current_bundle.bundle_body.len() {
                            return Err(EthApiError::InvalidParams(
                                EthSimBundleError::InvalidValidity.to_string(),
                            ));
                        }
                        if 100 - total_percent < refund.percent {
                            return Err(EthApiError::InvalidParams(
                                EthSimBundleError::InvalidValidity.to_string(),
                            ));
                        }
                        total_percent += refund.percent;
                    }
                }

                // Validate refund configs
                if let Some(refund_configs) = &validity.refund_config {
                    let mut total_percent = 0;
                    for refund_config in refund_configs {
                        if 100 - total_percent < refund_config.percent {
                            return Err(EthApiError::InvalidParams(
                                EthSimBundleError::InvalidValidity.to_string(),
                            ));
                        }
                        total_percent += refund_config.percent;
                    }
                }
            }

            let body = &current_bundle.bundle_body;

            // Process items in the current bundle
            while idx < body.len() {
                match &body[idx] {
                    BundleItem::Tx { tx, can_revert } => {
                        let recovered_tx = recover_raw_transaction::<PoolPooledTx<Eth::Pool>>(tx)?;
                        let tx = recovered_tx.map(
                            <Eth::Pool as TransactionPool>::Transaction::pooled_into_consensus,
                        );

                        let refund_percent =
                            validity.as_ref().and_then(|v| v.refund.as_ref()).and_then(|refunds| {
                                refunds.iter().find_map(|refund| {
                                    (refund.body_idx as usize == idx).then_some(refund.percent)
                                })
                            });
                        let refund_configs =
                            validity.as_ref().and_then(|v| v.refund_config.clone());

                        // Create FlattenedBundleItem with current inclusion, validity, and privacy
                        let flattened_item = FlattenedBundleItem {
                            tx,
                            can_revert: *can_revert,
                            inclusion: inclusion.clone(),
                            validity: validity.clone(),
                            privacy: privacy.clone(),
                            refund_percent,
                            refund_configs,
                        };

                        items.push(flattened_item);
                        idx += 1;
                    }
                    BundleItem::Bundle { bundle } => {
                        // Push the current bundle and next index onto the stack to resume later
                        stack.push((current_bundle, idx + 1, depth));

                        // process the nested bundle next
                        stack.push((bundle, 0, depth + 1));
                        break;
                    }
                    BundleItem::Hash { hash: _ } => {
                        // Hash-only items are not allowed
                        return Err(EthApiError::InvalidParams(
                            EthSimBundleError::InvalidBundle.to_string(),
                        ));
                    }
                }
            }
        }

        Ok(items)
    }

    async fn sim_bundle_inner(
        &self,
        request: MevSendBundle,
        overrides: SimBundleOverrides,
        logs: bool,
    ) -> Result<SimBundleResponse, Eth::Error> {
        let SimBundleOverrides { parent_block, block_overrides, .. } = overrides;

        // Parse and validate bundle
        // Also, flatten the bundle here so that its easier to process
        let flattened_bundle = self.parse_and_flatten_bundle(&request)?;

        let block_id = parent_block.unwrap_or(BlockId::Number(BlockNumberOrTag::Latest));
        let (mut evm_env, current_block_id) = self.eth_api().evm_env_at(block_id).await?;
        let current_block = self.eth_api().recovered_block(current_block_id).await?;
        let current_block = current_block.ok_or(EthApiError::HeaderNotFound(block_id))?;

        let eth_api = self.inner.eth_api.clone();

        let sim_response = self
            .inner
            .eth_api
            .spawn_with_state_at_block(current_block_id, move |_, mut db| {
                // Setup environment
                let current_block_number = current_block.number();
                let coinbase = evm_env.block_env.beneficiary();
                let basefee = evm_env.block_env.basefee();

                // apply overrides
                apply_block_overrides(block_overrides, &mut db, evm_env.block_env.inner_mut());

                let initial_coinbase_balance = DatabaseRef::basic_ref(&db, coinbase)
                    .map_err(EthApiError::from_eth_err)?
                    .map(|acc| acc.balance)
                    .unwrap_or_default();

                let mut coinbase_balance_before_tx = initial_coinbase_balance;
                let mut total_gas_used = 0;
                let mut total_profit = U256::ZERO;
                let mut refundable_value = U256::ZERO;
                let mut flat_logs: Vec<Vec<Log>> = Vec::new();

                let mut evm = eth_api.evm_config().evm_with_env(db, evm_env);
                let mut log_index = 0;

                for (tx_index, item) in flattened_bundle.iter().enumerate() {
                    // Check inclusion constraints
                    let block_number = item.inclusion.block_number();
                    let max_block_number =
                        item.inclusion.max_block_number().unwrap_or(block_number);

                    if current_block_number < block_number ||
                        current_block_number > max_block_number
                    {
                        return Err(EthApiError::InvalidParams(
                            EthSimBundleError::InvalidInclusion.to_string(),
                        )
                        .into());
                    }

                    let ResultAndState { result, state } = evm
                        .transact(eth_api.evm_config().tx_env(&item.tx))
                        .map_err(Eth::Error::from_evm_err)?;

                    if !result.is_success() && !item.can_revert {
                        return Err(EthApiError::InvalidParams(
                            EthSimBundleError::BundleTransactionFailed.to_string(),
                        )
                        .into());
                    }

                    let gas_used = result.gas_used();
                    total_gas_used += gas_used;

                    // coinbase is always present in the result state
                    let coinbase_balance_after_tx =
                        state.get(&coinbase).map(|acc| acc.info.balance).unwrap_or_default();

                    let coinbase_diff =
                        coinbase_balance_after_tx.saturating_sub(coinbase_balance_before_tx);
                    total_profit += coinbase_diff;

                    // Add to refundable value if this tx does not have a refund percent
                    if item.refund_percent.is_none() {
                        refundable_value += coinbase_diff;
                    }

                    // Update coinbase balance before next tx
                    coinbase_balance_before_tx = coinbase_balance_after_tx;

                    // Keep one log entry per executed transaction so we can rebuild the bundle
                    // tree in execution order after simulation.
                    if logs {
                        let tx_logs: Vec<Log> = result
                            .into_logs()
                            .into_iter()
                            .map(|inner| {
                                let full_log = Log {
                                    inner,
                                    block_hash: Some(current_block.hash()),
                                    block_number: Some(current_block.number()),
                                    block_timestamp: Some(current_block.timestamp()),
                                    transaction_hash: Some(*item.tx.tx_hash()),
                                    transaction_index: Some(tx_index as u64),
                                    log_index: Some(log_index),
                                    removed: false,
                                };
                                log_index += 1;
                                full_log
                            })
                            .collect();
                        flat_logs.push(tx_logs);
                    }

                    // Apply state changes
                    evm.db_mut().commit(state);
                }

                let body_logs =
                    if logs { Self::build_bundle_logs(&request, &flat_logs)? } else { vec![] };

                // After processing all transactions, process refunds
                // Store the original refundable value to calculate all payouts correctly
                let original_refundable_value = refundable_value;
                for item in &flattened_bundle {
                    if let Some(refund_percent) = item.refund_percent {
                        let refund_configs = item.refund_configs.clone().unwrap_or_else(|| {
                            vec![RefundConfig { address: item.tx.signer(), percent: 100 }]
                        });

                        // Calculate payout transaction fee
                        let payout_tx_fee = U256::from(basefee) *
                            U256::from(SBUNDLE_PAYOUT_MAX_COST) *
                            U256::from(refund_configs.len() as u64);

                        // Add gas used for payout transactions
                        total_gas_used += SBUNDLE_PAYOUT_MAX_COST * refund_configs.len() as u64;

                        // Calculate allocated refundable value (payout value) based on ORIGINAL
                        // refundable value. This ensures all refund_percent values are
                        // calculated from the same base.
                        let payout_value = original_refundable_value * U256::from(refund_percent) /
                            U256::from(100);

                        if payout_tx_fee > payout_value {
                            return Err(EthApiError::InvalidParams(
                                EthSimBundleError::NegativeProfit.to_string(),
                            )
                            .into());
                        }

                        // Subtract payout value from total profit
                        total_profit = total_profit.checked_sub(payout_value).ok_or(
                            EthApiError::InvalidParams(
                                EthSimBundleError::NegativeProfit.to_string(),
                            ),
                        )?;

                        // Adjust refundable value
                        refundable_value = refundable_value.checked_sub(payout_value).ok_or(
                            EthApiError::InvalidParams(
                                EthSimBundleError::NegativeProfit.to_string(),
                            ),
                        )?;
                    }
                }

                // Calculate mev gas price
                let mev_gas_price = if total_gas_used != 0 {
                    total_profit / U256::from(total_gas_used)
                } else {
                    U256::ZERO
                };

                Ok(SimBundleResponse {
                    success: true,
                    state_block: current_block_number,
                    error: None,
                    logs: Some(body_logs),
                    gas_used: total_gas_used,
                    mev_gas_price,
                    profit: total_profit,
                    refundable_value,
                    exec_error: None,
                    revert: None,
                })
            })
            .await?;

        Ok(sim_response)
    }
}

#[async_trait::async_trait]
impl<Eth> MevSimApiServer for EthSimBundle<Eth>
where
    Eth: EthTransactions + LoadBlock + Call + 'static,
{
    async fn sim_bundle(
        &self,
        request: MevSendBundle,
        overrides: SimBundleOverrides,
    ) -> RpcResult<SimBundleResponse> {
        trace!("mev_simBundle called, request: {:?}, overrides: {:?}", request, overrides);

        let override_timeout = overrides.timeout;

        let timeout = override_timeout
            .map(Duration::from_secs)
            .map(|d| d.min(MAX_SIM_TIMEOUT))
            .unwrap_or(DEFAULT_SIM_TIMEOUT);

        let bundle_res =
            tokio::time::timeout(timeout, Self::sim_bundle_inner(self, request, overrides, true))
                .await
                .map_err(|_| {
                    EthApiError::InvalidParams(EthSimBundleError::BundleTimeout.to_string())
                })?;

        bundle_res.map_err(Into::into)
    }
}

/// Container type for `EthSimBundle` internals
#[derive(Debug)]
struct EthSimBundleInner<Eth> {
    /// Access to commonly used code of the `eth` namespace
    eth_api: Eth,
    // restrict the number of concurrent tracing calls.
    #[expect(dead_code)]
    blocking_task_guard: BlockingTaskGuard,
}

impl<Eth> std::fmt::Debug for EthSimBundle<Eth> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("EthSimBundle").finish_non_exhaustive()
    }
}

impl<Eth> Clone for EthSimBundle<Eth> {
    fn clone(&self) -> Self {
        Self { inner: Arc::clone(&self.inner) }
    }
}

/// [`EthSimBundle`] specific errors.
#[derive(Debug, thiserror::Error)]
pub enum EthSimBundleError {
    /// Thrown when max depth is reached
    #[error("max depth reached")]
    MaxDepth,
    /// Thrown when a bundle is unmatched
    #[error("unmatched bundle")]
    UnmatchedBundle,
    /// Thrown when a bundle is too large
    #[error("bundle too large")]
    BundleTooLarge,
    /// Thrown when validity is invalid
    #[error("invalid validity")]
    InvalidValidity,
    /// Thrown when inclusion is invalid
    #[error("invalid inclusion")]
    InvalidInclusion,
    /// Thrown when a bundle is invalid
    #[error("invalid bundle")]
    InvalidBundle,
    /// Thrown when a bundle simulation times out
    #[error("bundle simulation timed out")]
    BundleTimeout,
    /// Thrown when a transaction is reverted in a bundle
    #[error("bundle transaction failed")]
    BundleTransactionFailed,
    /// Thrown when a bundle simulation returns negative profit
    #[error("bundle simulation returned negative profit")]
    NegativeProfit,
}

#[cfg(test)]
mod tests {
    use super::*;
    use alloy_primitives::Bytes;
    use alloy_rpc_types_mev::{Inclusion, ProtocolVersion};

    fn create_test_bundle(tx_bytes: Vec<Bytes>) -> MevSendBundle {
        let body: Vec<BundleItem> =
            tx_bytes.into_iter().map(|tx| BundleItem::Tx { tx, can_revert: false }).collect();
        MevSendBundle {
            bundle_body: body,
            inclusion: Inclusion { block: 1, max_block: None },
            validity: None,
            privacy: None,
            protocol_version: ProtocolVersion::V0_1,
        }
    }

    fn create_nested_bundle(outer_tx: Bytes, inner_txs: Vec<Bytes>) -> MevSendBundle {
        let inner_bundle = create_test_bundle(inner_txs);
        MevSendBundle {
            bundle_body: vec![
                BundleItem::Tx { tx: outer_tx, can_revert: false },
                BundleItem::Bundle { bundle: inner_bundle },
            ],
            inclusion: Inclusion { block: 1, max_block: None },
            validity: None,
            privacy: None,
            protocol_version: ProtocolVersion::V0_1,
        }
    }

    fn create_bundle_with_body(bundle_body: Vec<BundleItem>) -> MevSendBundle {
        MevSendBundle {
            bundle_body,
            inclusion: Inclusion { block: 1, max_block: None },
            validity: None,
            privacy: None,
            protocol_version: ProtocolVersion::V0_1,
        }
    }

    fn create_bundle_logs(log_counts: &[usize]) -> Vec<Vec<Log>> {
        log_counts.iter().map(|count| vec![Log::default(); *count]).collect()
    }

    fn assert_unmatched_bundle(result: Result<Vec<SimBundleLogs>, EthApiError>) {
        assert!(matches!(
            result,
            Err(EthApiError::InvalidParams(ref message))
                if message == &EthSimBundleError::UnmatchedBundle.to_string()
        ));
    }

    #[test]
    fn test_build_bundle_logs_single_tx() {
        let bundle = create_test_bundle(vec![Bytes::from(vec![0x01, 0x02, 0x03])]);
        let result =
            EthSimBundle::<()>::build_bundle_logs(&bundle, &create_bundle_logs(&[1])).unwrap();

        assert_eq!(result.len(), 1);
        assert!(result[0].tx_logs.is_some());
        assert!(result[0].bundle_logs.is_none());
        assert_eq!(result[0].tx_logs.as_ref().unwrap().len(), 1);
    }

    #[test]
    fn test_build_bundle_logs_empty_bundle() {
        let bundle = create_test_bundle(vec![]);
        let result = EthSimBundle::<()>::build_bundle_logs(&bundle, &[]).unwrap();

        assert!(result.is_empty());
    }

    #[test]
    fn test_build_bundle_logs_nested_bundle() {
        let outer_tx = Bytes::from(vec![0x01, 0x02, 0x03]);
        let inner_tx1 = Bytes::from(vec![0x04, 0x05, 0x06]);
        let inner_tx2 = Bytes::from(vec![0x07, 0x08, 0x09]);
        let bundle = create_nested_bundle(outer_tx, vec![inner_tx1, inner_tx2]);
        let result =
            EthSimBundle::<()>::build_bundle_logs(&bundle, &create_bundle_logs(&[1, 1, 2]))
                .unwrap();

        assert_eq!(result.len(), 2);
        assert!(result[0].tx_logs.is_some());
        assert!(result[0].bundle_logs.is_none());
        assert_eq!(result[0].tx_logs.as_ref().unwrap().len(), 1);

        assert!(result[1].tx_logs.is_none());
        assert!(result[1].bundle_logs.is_some());

        let nested_logs = result[1].bundle_logs.as_ref().unwrap();
        assert_eq!(nested_logs.len(), 2);
        assert!(nested_logs[0].tx_logs.is_some());
        assert_eq!(nested_logs[0].tx_logs.as_ref().unwrap().len(), 1);
        assert!(nested_logs[1].tx_logs.is_some());
        assert_eq!(nested_logs[1].tx_logs.as_ref().unwrap().len(), 2);
    }

    #[test]
    fn test_build_bundle_logs_duplicate_transactions_same_level() {
        let duplicate_tx = Bytes::from(vec![0x01, 0x02, 0x03]);
        let bundle = create_test_bundle(vec![duplicate_tx.clone(), duplicate_tx]);
        let result =
            EthSimBundle::<()>::build_bundle_logs(&bundle, &create_bundle_logs(&[1, 2])).unwrap();

        assert_eq!(result.len(), 2);
        assert_eq!(result[0].tx_logs.as_ref().unwrap().len(), 1);
        assert_eq!(result[1].tx_logs.as_ref().unwrap().len(), 2);
    }

    #[test]
    fn test_build_bundle_logs_duplicate_transactions_across_nested_bundles() {
        let duplicate_tx = Bytes::from(vec![0x01, 0x02, 0x03]);
        let bundle = create_nested_bundle(duplicate_tx.clone(), vec![duplicate_tx]);
        let result =
            EthSimBundle::<()>::build_bundle_logs(&bundle, &create_bundle_logs(&[1, 2])).unwrap();

        assert_eq!(result.len(), 2);
        assert!(result[1].bundle_logs.is_some());
        assert_eq!(result[0].tx_logs.as_ref().unwrap().len(), 1);

        let nested_logs = result[1].bundle_logs.as_ref().unwrap();
        assert_eq!(nested_logs.len(), 1);
        assert_eq!(nested_logs[0].tx_logs.as_ref().unwrap().len(), 2);
    }

    #[test]
    fn test_build_bundle_logs_root_with_only_nested_bundles() {
        let first_nested = create_test_bundle(vec![Bytes::from(vec![0x01])]);
        let second_nested =
            create_test_bundle(vec![Bytes::from(vec![0x02]), Bytes::from(vec![0x03])]);
        let bundle = create_bundle_with_body(vec![
            BundleItem::Bundle { bundle: first_nested },
            BundleItem::Bundle { bundle: second_nested },
        ]);
        let result =
            EthSimBundle::<()>::build_bundle_logs(&bundle, &create_bundle_logs(&[1, 1, 2]))
                .unwrap();

        assert_eq!(result.len(), 2);
        assert!(result[0].tx_logs.is_none());
        assert!(result[1].tx_logs.is_none());

        let first_nested_logs = result[0].bundle_logs.as_ref().unwrap();
        assert_eq!(first_nested_logs.len(), 1);
        assert_eq!(first_nested_logs[0].tx_logs.as_ref().unwrap().len(), 1);

        let second_nested_logs = result[1].bundle_logs.as_ref().unwrap();
        assert_eq!(second_nested_logs.len(), 2);
        assert_eq!(second_nested_logs[0].tx_logs.as_ref().unwrap().len(), 1);
        assert_eq!(second_nested_logs[1].tx_logs.as_ref().unwrap().len(), 2);
    }

    #[test]
    fn test_build_bundle_logs_deeply_nested_bundle() {
        let leaf_bundle = create_test_bundle(vec![Bytes::from(vec![0x03])]);
        let middle_bundle = create_bundle_with_body(vec![
            BundleItem::Tx { tx: Bytes::from(vec![0x02]), can_revert: false },
            BundleItem::Bundle { bundle: leaf_bundle },
        ]);
        let root_bundle = create_bundle_with_body(vec![
            BundleItem::Tx { tx: Bytes::from(vec![0x01]), can_revert: false },
            BundleItem::Bundle { bundle: middle_bundle },
        ]);
        let result =
            EthSimBundle::<()>::build_bundle_logs(&root_bundle, &create_bundle_logs(&[1, 2, 3]))
                .unwrap();

        assert_eq!(result.len(), 2);
        assert_eq!(result[0].tx_logs.as_ref().unwrap().len(), 1);

        let middle_logs = result[1].bundle_logs.as_ref().unwrap();
        assert_eq!(middle_logs.len(), 2);
        assert_eq!(middle_logs[0].tx_logs.as_ref().unwrap().len(), 2);

        let leaf_logs = middle_logs[1].bundle_logs.as_ref().unwrap();
        assert_eq!(leaf_logs.len(), 1);
        assert_eq!(leaf_logs[0].tx_logs.as_ref().unwrap().len(), 3);
    }

    #[test]
    fn test_build_bundle_logs_mismatched_flat_logs() {
        let bundle = create_test_bundle(vec![Bytes::from(vec![0x01, 0x02, 0x03])]);

        assert_unmatched_bundle(EthSimBundle::<()>::build_bundle_logs(&bundle, &[]));
        assert_unmatched_bundle(EthSimBundle::<()>::build_bundle_logs(
            &bundle,
            &create_bundle_logs(&[1, 2]),
        ));
    }
}