reth_trie_common/

proofs.rs

//! Merkle trie proofs.

use crate::{BranchNodeMasks, BranchNodeMasksMap, Nibbles, ProofTrieNodeV2, TrieAccount};
use alloc::{borrow::Cow, collections::VecDeque, vec::Vec};
use alloy_consensus::constants::KECCAK_EMPTY;
use alloy_primitives::{
    keccak256,
    map::{hash_map, B256Map, B256Set},
    Address, Bytes, B256, U256,
};
use alloy_rlp::{encode_fixed_size, Decodable, EMPTY_STRING_CODE};
use alloy_trie::{
    nodes::TrieNode,
    proof::{verify_proof, DecodedProofNodes, ProofNodes, ProofVerificationError},
    EMPTY_ROOT_HASH,
};
use derive_more::{Deref, DerefMut, IntoIterator};
use itertools::Itertools;
use reth_primitives_traits::Account;

/// Proof targets map.
#[derive(Deref, DerefMut, IntoIterator, Clone, PartialEq, Eq, Default, Debug)]
pub struct MultiProofTargets(B256Map<B256Set>);

impl FromIterator<(B256, B256Set)> for MultiProofTargets {
    fn from_iter<T: IntoIterator<Item = (B256, B256Set)>>(iter: T) -> Self {
        Self(B256Map::from_iter(iter))
    }
}

impl MultiProofTargets {
    /// Creates an empty `MultiProofTargets` with at least the specified capacity.
    pub fn with_capacity(capacity: usize) -> Self {
        Self(B256Map::with_capacity_and_hasher(capacity, Default::default()))
    }

    /// Create `MultiProofTargets` with a single account as a target.
    pub fn account(hashed_address: B256) -> Self {
        Self::accounts([hashed_address])
    }

    /// Create `MultiProofTargets` with a single account and slots as targets.
    pub fn account_with_slots<I: IntoIterator<Item = B256>>(
        hashed_address: B256,
        slots_iter: I,
    ) -> Self {
        Self(B256Map::from_iter([(hashed_address, slots_iter.into_iter().collect())]))
    }

    /// Create `MultiProofTargets` only from accounts.
    pub fn accounts<I: IntoIterator<Item = B256>>(iter: I) -> Self {
        Self(iter.into_iter().map(|hashed_address| (hashed_address, Default::default())).collect())
    }

    /// Retains the targets representing the difference,
    /// i.e., the values that are in `self` but not in `other`.
    pub fn retain_difference(&mut self, other: &Self) {
        self.0.retain(|hashed_address, hashed_slots| {
            if let Some(other_hashed_slots) = other.get(hashed_address) {
                hashed_slots.retain(|hashed_slot| !other_hashed_slots.contains(hashed_slot));
                !hashed_slots.is_empty()
            } else {
                true
            }
        });
    }

    /// Extend multi proof targets with contents of other.
    pub fn extend(&mut self, other: Self) {
        self.extend_inner(Cow::Owned(other));
    }

    /// Extend multi proof targets with contents of other.
    ///
    /// Slightly less efficient than [`Self::extend`], but preferred to `extend(other.clone())`.
    pub fn extend_ref(&mut self, other: &Self) {
        self.extend_inner(Cow::Borrowed(other));
    }

    fn extend_inner(&mut self, other: Cow<'_, Self>) {
        for (hashed_address, hashed_slots) in other.iter() {
            match self.entry(*hashed_address) {
                hash_map::Entry::Vacant(entry) => {
                    entry.insert(hashed_slots.clone());
                }
                hash_map::Entry::Occupied(mut entry) => {
                    entry.get_mut().extend(hashed_slots);
                }
            }
        }
    }

    /// Returns an iterator that yields chunks of the specified size.
    ///
    /// See [`ChunkedMultiProofTargets`] for more information.
    pub fn chunks(self, size: usize) -> ChunkedMultiProofTargets {
        ChunkedMultiProofTargets::new(self, size)
    }

    /// Returns the number of items that will be considered during chunking in `[Self::chunks]`.
    pub fn chunking_length(&self) -> usize {
        self.values().map(|slots| 1 + slots.len().saturating_sub(1)).sum::<usize>()
    }
}

/// An iterator that yields chunks of the proof targets of at most `size` account and storage
/// targets.
///
/// For example, for the following proof targets:
/// ```text
/// - 0x1: [0x10, 0x20, 0x30]
/// - 0x2: [0x40]
/// - 0x3: []
/// ```
///
/// and `size = 2`, the iterator will yield the following chunks:
/// ```text
/// - { 0x1: [0x10, 0x20] }
/// - { 0x1: [0x30], 0x2: [0x40] }
/// - { 0x3: [] }
/// ```
///
/// It follows two rules:
/// - If account has associated storage slots, each storage slot is counted towards the chunk size.
/// - If account has no associated storage slots, the account is counted towards the chunk size.
#[derive(Debug)]
pub struct ChunkedMultiProofTargets {
    flattened_targets: alloc::vec::IntoIter<(B256, Option<B256>)>,
    size: usize,
}

impl ChunkedMultiProofTargets {
    fn new(targets: MultiProofTargets, size: usize) -> Self {
        let flattened_targets = targets
            .into_iter()
            .flat_map(|(address, slots)| {
                if slots.is_empty() {
                    // If the account has no storage slots, we still need to yield the account
                    // address with empty storage slots. `None` here means that
                    // there's no storage slot to fetch.
                    itertools::Either::Left(core::iter::once((address, None)))
                } else {
                    itertools::Either::Right(
                        slots.into_iter().map(move |slot| (address, Some(slot))),
                    )
                }
            })
            .sorted_unstable();
        Self { flattened_targets, size }
    }
}

impl Iterator for ChunkedMultiProofTargets {
    type Item = MultiProofTargets;

    fn next(&mut self) -> Option<Self::Item> {
        let chunk = self.flattened_targets.by_ref().take(self.size).fold(
            MultiProofTargets::default(),
            |mut acc, (address, slot)| {
                let entry = acc.entry(address).or_default();
                if let Some(slot) = slot {
                    entry.insert(slot);
                }
                acc
            },
        );

        if chunk.is_empty() {
            None
        } else {
            Some(chunk)
        }
    }
}

/// The state multiproof of target accounts and multiproofs of their storage tries.
/// Multiproof is effectively a state subtrie that only contains the nodes
/// in the paths of target accounts.
#[derive(Clone, Default, Debug, PartialEq, Eq)]
pub struct MultiProof {
    /// State trie multiproof for requested accounts.
    pub account_subtree: ProofNodes,
    /// Consolidated branch node masks (`hash_mask`, `tree_mask`) for each path in the account
    /// proof.
    pub branch_node_masks: BranchNodeMasksMap,
    /// Storage trie multiproofs.
    pub storages: B256Map<StorageMultiProof>,
}

impl MultiProof {
    /// Returns true if the multiproof is empty.
    pub fn is_empty(&self) -> bool {
        self.account_subtree.is_empty() &&
            self.branch_node_masks.is_empty() &&
            self.storages.is_empty()
    }

    /// Return the account proof nodes for the given account path.
    pub fn account_proof_nodes(&self, path: &Nibbles) -> Vec<(Nibbles, Bytes)> {
        self.account_subtree.matching_nodes_sorted(path)
    }

    /// Return the storage proof nodes for the given storage slots of the account path.
    pub fn storage_proof_nodes(
        &self,
        hashed_address: B256,
        slots: impl IntoIterator<Item = B256>,
    ) -> Vec<(B256, Vec<(Nibbles, Bytes)>)> {
        self.storages
            .get(&hashed_address)
            .map(|storage_mp| {
                slots
                    .into_iter()
                    .map(|slot| {
                        let nibbles = Nibbles::unpack(slot);
                        (slot, storage_mp.subtree.matching_nodes_sorted(&nibbles))
                    })
                    .collect()
            })
            .unwrap_or_default()
    }

    /// Construct the account proof from the multiproof.
    pub fn account_proof(
        &self,
        address: Address,
        slots: &[B256],
    ) -> Result<AccountProof, alloy_rlp::Error> {
        let hashed_address = keccak256(address);
        let nibbles = Nibbles::unpack(hashed_address);

        // Retrieve the account proof.
        let proof = self
            .account_proof_nodes(&nibbles)
            .into_iter()
            .map(|(_, node)| node)
            .collect::<Vec<_>>();

        // Inspect the last node in the proof. If it's a leaf node with matching suffix,
        // then the node contains the encoded trie account.
        let info = 'info: {
            if let Some(last) = proof.last() &&
                let TrieNode::Leaf(leaf) = TrieNode::decode(&mut &last[..])? &&
                nibbles.ends_with(&leaf.key)
            {
                let account = TrieAccount::decode(&mut &leaf.value[..])?;
                break 'info Some(Account {
                    balance: account.balance,
                    nonce: account.nonce,
                    bytecode_hash: (account.code_hash != KECCAK_EMPTY).then_some(account.code_hash),
                })
            }
            None
        };

        // Retrieve proofs for requested storage slots.
        let storage_multiproof = self.storages.get(&hashed_address);
        let storage_root = storage_multiproof.map(|m| m.root).unwrap_or(EMPTY_ROOT_HASH);
        let mut storage_proofs = Vec::with_capacity(slots.len());
        for slot in slots {
            let proof = if let Some(multiproof) = &storage_multiproof {
                multiproof.storage_proof(*slot)?
            } else {
                StorageProof::new(*slot)
            };
            storage_proofs.push(proof);
        }
        Ok(AccountProof { address, info, proof, storage_root, storage_proofs })
    }

    /// Extends this multiproof with another one, merging both account and storage
    /// proofs.
    pub fn extend(&mut self, other: Self) {
        self.account_subtree.extend_from(other.account_subtree);
        self.branch_node_masks.extend(other.branch_node_masks);

        let reserve = if self.storages.is_empty() {
            other.storages.len()
        } else {
            other.storages.len().div_ceil(2)
        };
        self.storages.reserve(reserve);
        for (hashed_address, storage) in other.storages {
            match self.storages.entry(hashed_address) {
                hash_map::Entry::Occupied(mut entry) => {
                    debug_assert_eq!(entry.get().root, storage.root);
                    let entry = entry.get_mut();
                    entry.subtree.extend_from(storage.subtree);
                    entry.branch_node_masks.extend(storage.branch_node_masks);
                }
                hash_map::Entry::Vacant(entry) => {
                    entry.insert(storage);
                }
            }
        }
    }

    /// Create a [`MultiProof`] from a [`StorageMultiProof`].
    pub fn from_storage_proof(hashed_address: B256, storage_proof: StorageMultiProof) -> Self {
        Self {
            storages: B256Map::from_iter([(hashed_address, storage_proof)]),
            ..Default::default()
        }
    }
}

/// This is a type of [`MultiProof`] that uses decoded proofs, meaning these proofs are stored as a
/// collection of [`TrieNode`]s instead of RLP-encoded bytes.
#[derive(Clone, Default, Debug, PartialEq, Eq)]
pub struct DecodedMultiProof {
    /// State trie multiproof for requested accounts.
    pub account_subtree: DecodedProofNodes,
    /// Consolidated branch node masks (`hash_mask`, `tree_mask`) for each path in the account
    /// proof.
    pub branch_node_masks: BranchNodeMasksMap,
    /// Storage trie multiproofs.
    pub storages: B256Map<DecodedStorageMultiProof>,
}

impl DecodedMultiProof {
    /// Returns true if the multiproof is empty.
    pub fn is_empty(&self) -> bool {
        self.account_subtree.is_empty() &&
            self.branch_node_masks.is_empty() &&
            self.storages.is_empty()
    }

    /// Return the account proof nodes for the given account path.
    pub fn account_proof_nodes(&self, path: &Nibbles) -> Vec<(Nibbles, TrieNode)> {
        self.account_subtree.matching_nodes_sorted(path)
    }

    /// Return the storage proof nodes for the given storage slots of the account path.
    pub fn storage_proof_nodes(
        &self,
        hashed_address: B256,
        slots: impl IntoIterator<Item = B256>,
    ) -> Vec<(B256, Vec<(Nibbles, TrieNode)>)> {
        self.storages
            .get(&hashed_address)
            .map(|storage_mp| {
                slots
                    .into_iter()
                    .map(|slot| {
                        let nibbles = Nibbles::unpack(slot);
                        (slot, storage_mp.subtree.matching_nodes_sorted(&nibbles))
                    })
                    .collect()
            })
            .unwrap_or_default()
    }

    /// Construct the account proof from the multiproof.
    pub fn account_proof(
        &self,
        address: Address,
        slots: &[B256],
    ) -> Result<DecodedAccountProof, alloy_rlp::Error> {
        let hashed_address = keccak256(address);
        let nibbles = Nibbles::unpack(hashed_address);

        // Retrieve the account proof.
        let proof = self
            .account_proof_nodes(&nibbles)
            .into_iter()
            .map(|(_, node)| node)
            .collect::<Vec<_>>();

        // Inspect the last node in the proof. If it's a leaf node with matching suffix,
        // then the node contains the encoded trie account.
        let info = 'info: {
            if let Some(TrieNode::Leaf(leaf)) = proof.last() &&
                nibbles.ends_with(&leaf.key)
            {
                let account = TrieAccount::decode(&mut &leaf.value[..])?;
                break 'info Some(Account {
                    balance: account.balance,
                    nonce: account.nonce,
                    bytecode_hash: (account.code_hash != KECCAK_EMPTY).then_some(account.code_hash),
                })
            }
            None
        };

        // Retrieve proofs for requested storage slots.
        let storage_multiproof = self.storages.get(&hashed_address);
        let storage_root = storage_multiproof.map(|m| m.root).unwrap_or(EMPTY_ROOT_HASH);
        let mut storage_proofs = Vec::with_capacity(slots.len());
        for slot in slots {
            let proof = if let Some(multiproof) = &storage_multiproof {
                multiproof.storage_proof(*slot)?
            } else {
                DecodedStorageProof::new(*slot)
            };
            storage_proofs.push(proof);
        }
        Ok(DecodedAccountProof { address, info, proof, storage_root, storage_proofs })
    }

    /// Extends this multiproof with another one, merging both account and storage
    /// proofs.
    pub fn extend(&mut self, other: Self) {
        self.account_subtree.extend_from(other.account_subtree);
        self.branch_node_masks.extend(other.branch_node_masks);

        let reserve = if self.storages.is_empty() {
            other.storages.len()
        } else {
            other.storages.len().div_ceil(2)
        };
        self.storages.reserve(reserve);
        for (hashed_address, storage) in other.storages {
            match self.storages.entry(hashed_address) {
                hash_map::Entry::Occupied(mut entry) => {
                    debug_assert_eq!(entry.get().root, storage.root);
                    let entry = entry.get_mut();
                    entry.subtree.extend_from(storage.subtree);
                    entry.branch_node_masks.extend(storage.branch_node_masks);
                }
                hash_map::Entry::Vacant(entry) => {
                    entry.insert(storage);
                }
            }
        }
    }

    /// Create a [`DecodedMultiProof`] from a [`DecodedStorageMultiProof`].
    pub fn from_storage_proof(
        hashed_address: B256,
        storage_proof: DecodedStorageMultiProof,
    ) -> Self {
        Self {
            storages: B256Map::from_iter([(hashed_address, storage_proof)]),
            ..Default::default()
        }
    }
}

impl TryFrom<MultiProof> for DecodedMultiProof {
    type Error = alloy_rlp::Error;

    fn try_from(multi_proof: MultiProof) -> Result<Self, Self::Error> {
        let account_subtree = DecodedProofNodes::try_from(multi_proof.account_subtree)?;
        let storages = multi_proof
            .storages
            .into_iter()
            .map(|(address, storage)| Ok((address, storage.try_into()?)))
            .collect::<Result<B256Map<_>, alloy_rlp::Error>>()?;
        Ok(Self { account_subtree, branch_node_masks: multi_proof.branch_node_masks, storages })
    }
}

/// V2 decoded multiproof which contains the results of both account and storage V2 proof
/// calculations.
#[derive(Clone, Debug, PartialEq, Eq, Default)]
pub struct DecodedMultiProofV2 {
    /// Account trie proof nodes
    pub account_proofs: Vec<ProofTrieNodeV2>,
    /// Storage trie proof nodes indexed by account
    pub storage_proofs: B256Map<Vec<ProofTrieNodeV2>>,
}

impl DecodedMultiProofV2 {
    /// Returns true if there are no proofs
    pub fn is_empty(&self) -> bool {
        self.account_proofs.is_empty() && self.storage_proofs.is_empty()
    }

    /// Builds a `DecodedMultiProofV2` from a flat witness map (hash → RLP-encoded trie node).
    ///
    /// This performs a BFS traversal starting from `state_root`, decoding each witness entry
    /// as a trie node and organizing them into account and storage proof vectors. This is the
    /// inverse of witness generation — it reconstructs the structured multiproof from the flat
    /// format used in `ExecutionWitness`.
    pub fn from_witness(
        state_root: B256,
        witness: &B256Map<impl AsRef<[u8]>>,
    ) -> Result<Self, alloy_rlp::Error> {
        let mut account_nodes: Vec<(Nibbles, TrieNode, Option<BranchNodeMasks>)> = Vec::new();
        let mut storage_nodes: B256Map<Vec<(Nibbles, TrieNode, Option<BranchNodeMasks>)>> =
            B256Map::default();

        let mut queue: VecDeque<(B256, Nibbles, Option<B256>)> =
            VecDeque::from([(state_root, Nibbles::default(), None)]);

        while let Some((hash, path, maybe_account)) = queue.pop_front() {
            let Some(rlp_bytes) = witness.get(&hash) else { continue };
            let trie_node = TrieNode::decode(&mut rlp_bytes.as_ref())?;

            match &trie_node {
                TrieNode::Branch(branch) => {
                    for (idx, maybe_child) in branch.as_ref().children() {
                        if let Some(child_hash) =
                            maybe_child.and_then(alloy_trie::nodes::RlpNode::as_hash)
                        {
                            let mut child_path = path;
                            child_path.push_unchecked(idx);
                            queue.push_back((child_hash, child_path, maybe_account));
                        }
                    }
                }
                TrieNode::Extension(ext) => {
                    if let Some(child_hash) = ext.child.as_hash() {
                        let mut child_path = path;
                        child_path.extend(&ext.key);
                        queue.push_back((child_hash, child_path, maybe_account));
                    }
                }
                TrieNode::Leaf(leaf) => {
                    if maybe_account.is_none() {
                        let mut full_path = path;
                        full_path.extend(&leaf.key);
                        let hashed_address = B256::from_slice(&full_path.pack());
                        let account = TrieAccount::decode(&mut &leaf.value[..])?;
                        if account.storage_root != EMPTY_ROOT_HASH {
                            queue.push_back((
                                account.storage_root,
                                Nibbles::default(),
                                Some(hashed_address),
                            ));
                        }
                    }
                }
                TrieNode::EmptyRoot => {}
            }

            if let Some(account) = maybe_account {
                storage_nodes.entry(account).or_default().push((path, trie_node, None));
            } else {
                account_nodes.push((path, trie_node, None));
            }
        }

        account_nodes.sort_by(|(a, _, _), (b, _, _)| crate::depth_first_cmp(a, b));
        let account_proofs = ProofTrieNodeV2::from_sorted_trie_nodes(account_nodes);

        let mut storage_proofs = B256Map::default();
        for (account, mut nodes) in storage_nodes {
            nodes.sort_by(|(a, _, _), (b, _, _)| crate::depth_first_cmp(a, b));
            storage_proofs.insert(account, ProofTrieNodeV2::from_sorted_trie_nodes(nodes));
        }

        Ok(Self { account_proofs, storage_proofs })
    }

    /// Appends the given multiproof's data to this one.
    ///
    /// This implementation does not deduplicate redundant proofs.
    pub fn extend(&mut self, other: Self) {
        self.account_proofs.extend(other.account_proofs);
        for (hashed_address, other_storage_proofs) in other.storage_proofs {
            match self.storage_proofs.entry(hashed_address) {
                hash_map::Entry::Vacant(entry) => {
                    entry.insert(other_storage_proofs);
                }
                hash_map::Entry::Occupied(mut entry) => {
                    entry.get_mut().extend(other_storage_proofs);
                }
            }
        }
    }
}

impl From<DecodedMultiProof> for DecodedMultiProofV2 {
    fn from(proof: DecodedMultiProof) -> Self {
        let account_proofs =
            decoded_proof_nodes_to_v2(proof.account_subtree, &proof.branch_node_masks);
        let storage_proofs = proof
            .storages
            .into_iter()
            .map(|(address, storage)| {
                (address, decoded_proof_nodes_to_v2(storage.subtree, &storage.branch_node_masks))
            })
            .collect();
        Self { account_proofs, storage_proofs }
    }
}

/// Converts a [`DecodedProofNodes`] (path → [`TrieNode`] map) into a `Vec<ProofTrieNodeV2>`,
/// merging extension nodes into their child branch nodes.
fn decoded_proof_nodes_to_v2(
    nodes: DecodedProofNodes,
    masks: &BranchNodeMasksMap,
) -> Vec<ProofTrieNodeV2> {
    let mut sorted: Vec<_> = nodes.into_inner().into_iter().collect();
    sorted.sort_unstable_by(|a, b| crate::depth_first_cmp(&a.0, &b.0));
    ProofTrieNodeV2::from_sorted_trie_nodes(
        sorted.into_iter().map(|(path, node)| (path, node, masks.get(&path).copied())),
    )
}

/// The merkle multiproof of storage trie.
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct StorageMultiProof {
    /// Storage trie root.
    pub root: B256,
    /// Storage multiproof for requested slots.
    pub subtree: ProofNodes,
    /// Consolidated branch node masks (`hash_mask`, `tree_mask`) for each path in the storage
    /// proof.
    pub branch_node_masks: BranchNodeMasksMap,
}

impl StorageMultiProof {
    /// Create new storage multiproof for empty trie.
    pub fn empty() -> Self {
        Self {
            root: EMPTY_ROOT_HASH,
            subtree: ProofNodes::from_iter([(
                Nibbles::default(),
                Bytes::from([EMPTY_STRING_CODE]),
            )]),
            branch_node_masks: BranchNodeMasksMap::default(),
        }
    }

    /// Return storage proofs for the target storage slot (unhashed).
    pub fn storage_proof(&self, slot: B256) -> Result<StorageProof, alloy_rlp::Error> {
        let nibbles = Nibbles::unpack(keccak256(slot));

        // Retrieve the storage proof.
        let proof = self
            .subtree
            .matching_nodes_iter(&nibbles)
            .sorted_by(|a, b| a.0.cmp(b.0))
            .map(|(_, node)| node.clone())
            .collect::<Vec<_>>();

        // Inspect the last node in the proof. If it's a leaf node with matching suffix,
        // then the node contains the encoded slot value.
        let value = 'value: {
            if let Some(last) = proof.last() &&
                let TrieNode::Leaf(leaf) = TrieNode::decode(&mut &last[..])? &&
                nibbles.ends_with(&leaf.key)
            {
                break 'value U256::decode(&mut &leaf.value[..])?
            }
            U256::ZERO
        };

        Ok(StorageProof { key: slot, nibbles, value, proof })
    }
}

/// The decoded merkle multiproof for a storage trie.
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct DecodedStorageMultiProof {
    /// Storage trie root.
    pub root: B256,
    /// Storage multiproof for requested slots.
    pub subtree: DecodedProofNodes,
    /// Consolidated branch node masks (`hash_mask`, `tree_mask`) for each path in the storage
    /// proof.
    pub branch_node_masks: BranchNodeMasksMap,
}

impl DecodedStorageMultiProof {
    /// Create new storage multiproof for empty trie.
    pub fn empty() -> Self {
        Self {
            root: EMPTY_ROOT_HASH,
            subtree: DecodedProofNodes::from_iter([(Nibbles::default(), TrieNode::EmptyRoot)]),
            branch_node_masks: BranchNodeMasksMap::default(),
        }
    }

    /// Return storage proofs for the target storage slot (unhashed).
    pub fn storage_proof(&self, slot: B256) -> Result<DecodedStorageProof, alloy_rlp::Error> {
        let nibbles = Nibbles::unpack(keccak256(slot));

        // Retrieve the storage proof.
        let proof = self
            .subtree
            .matching_nodes_iter(&nibbles)
            .sorted_by(|a, b| a.0.cmp(b.0))
            .map(|(_, node)| node.clone())
            .collect::<Vec<_>>();

        // Inspect the last node in the proof. If it's a leaf node with matching suffix,
        // then the node contains the encoded slot value.
        let value = 'value: {
            if let Some(TrieNode::Leaf(leaf)) = proof.last() &&
                nibbles.ends_with(&leaf.key)
            {
                break 'value U256::decode(&mut &leaf.value[..])?
            }
            U256::ZERO
        };

        Ok(DecodedStorageProof { key: slot, nibbles, value, proof })
    }
}

impl TryFrom<StorageMultiProof> for DecodedStorageMultiProof {
    type Error = alloy_rlp::Error;

    fn try_from(multi_proof: StorageMultiProof) -> Result<Self, Self::Error> {
        let subtree = DecodedProofNodes::try_from(multi_proof.subtree)?;
        Ok(Self {
            root: multi_proof.root,
            subtree,
            branch_node_masks: multi_proof.branch_node_masks,
        })
    }
}

/// The merkle proof with the relevant account info.
#[derive(Clone, PartialEq, Eq, Debug)]
#[cfg_attr(any(test, feature = "serde"), derive(serde::Serialize, serde::Deserialize))]
#[cfg_attr(any(test, feature = "serde"), serde(rename_all = "camelCase"))]
pub struct AccountProof {
    /// The address associated with the account.
    pub address: Address,
    /// Account info, if any.
    pub info: Option<Account>,
    /// Array of rlp-serialized merkle trie nodes which starting from the root node and
    /// following the path of the hashed address as key.
    pub proof: Vec<Bytes>,
    /// The storage trie root.
    pub storage_root: B256,
    /// Array of storage proofs as requested.
    pub storage_proofs: Vec<StorageProof>,
}

/// Normalize an empty-trie proof for the EIP-1186 (`eth_getProof`) response.
///
/// An empty trie is internally represented by a single empty-root sentinel node (`0x80`, the
/// RLP empty string whose hash is `EMPTY_ROOT_HASH`). EIP-1186 defines the proof field as the
/// array of trie nodes along the key path; an empty trie has none, and geth returns `[]`. This
/// strips that lone sentinel so the response matches geth and the spec. It is applied only at
/// the response boundary, leaving the underlying proof construction unchanged.
#[cfg(feature = "eip1186")]
fn normalize_eip1186_empty_trie_proof(proof: Vec<Bytes>) -> Vec<Bytes> {
    if proof.len() == 1 && proof[0].as_ref() == [EMPTY_STRING_CODE] {
        Vec::new()
    } else {
        proof
    }
}

#[cfg(feature = "eip1186")]
impl AccountProof {
    /// Convert into an EIP-1186 account proof response.
    ///
    /// For non-existent accounts, this returns `KECCAK_EMPTY` for `codeHash` and
    /// `EMPTY_ROOT_HASH` for `storageHash`, matching reth's default behavior.
    ///
    /// Use [`Self::into_eip1186_response_with`] to customize the behavior for
    /// non-existent accounts (e.g. returning `B256::ZERO` for geth compatibility).
    pub fn into_eip1186_response(
        self,
        slots: Vec<alloy_serde::JsonStorageKey>,
    ) -> alloy_rpc_types_eth::EIP1186AccountProofResponse {
        self.into_eip1186_response_with(slots, false)
    }

    /// Convert into an EIP-1186 account proof response, with optional geth-compatible
    /// zero hashes for non-existent accounts.
    ///
    /// When `zero_empty_account` is `true`, non-existent accounts return `B256::ZERO`
    /// for both `codeHash` and `storageHash`, matching geth's behavior since v1.13.4
    /// ([go-ethereum#28357](https://github.com/ethereum/go-ethereum/pull/28357)).
    ///
    /// When `false`, returns `KECCAK_EMPTY` / `EMPTY_ROOT_HASH` (reth default).
    ///
    /// See: <https://github.com/ethereum/go-ethereum/issues/28441>
    pub fn into_eip1186_response_with(
        self,
        slots: Vec<alloy_serde::JsonStorageKey>,
        zero_empty_account: bool,
    ) -> alloy_rpc_types_eth::EIP1186AccountProofResponse {
        let is_non_existent = self.info.is_none();
        let info = self.info.unwrap_or_default();
        let (code_hash, storage_hash) = if is_non_existent && zero_empty_account {
            (B256::ZERO, B256::ZERO)
        } else {
            (info.get_bytecode_hash(), self.storage_root)
        };
        alloy_rpc_types_eth::EIP1186AccountProofResponse {
            address: self.address,
            balance: info.balance,
            code_hash,
            nonce: info.nonce,
            storage_hash,
            account_proof: normalize_eip1186_empty_trie_proof(self.proof),
            storage_proof: self
                .storage_proofs
                .into_iter()
                .filter_map(|proof| {
                    let input_slot = slots.iter().find(|s| s.as_b256() == proof.key)?;
                    Some(proof.into_eip1186_proof(*input_slot))
                })
                .collect(),
        }
    }

    /// Converts an
    /// [`EIP1186AccountProofResponse`](alloy_rpc_types_eth::EIP1186AccountProofResponse) to an
    /// [`AccountProof`].
    ///
    /// This is the inverse of [`Self::into_eip1186_response`]
    pub fn from_eip1186_proof(proof: alloy_rpc_types_eth::EIP1186AccountProofResponse) -> Self {
        let alloy_rpc_types_eth::EIP1186AccountProofResponse {
            nonce,
            address,
            balance,
            code_hash,
            storage_hash,
            account_proof,
            storage_proof,
            ..
        } = proof;
        let storage_proofs = storage_proof.into_iter().map(Into::into).collect();

        let (storage_root, info) = if nonce == 0 &&
            balance.is_zero() &&
            (storage_hash.is_zero() || storage_hash == EMPTY_ROOT_HASH) &&
            (code_hash == KECCAK_EMPTY || code_hash.is_zero())
        {
            // Account does not exist in state. Return `None` here to prevent proof
            // verification.
            //
            // Note: geth (since v1.13.4, go-ethereum#28357) returns `B256::ZERO` for
            // both `codeHash` and `storageHash` in exclusion proofs, while reth
            // returns `KECCAK_EMPTY` / `EMPTY_ROOT_HASH`. We accept both formats here
            // so that proofs obtained from any client can be deserialized correctly.
            // See: https://github.com/ethereum/go-ethereum/issues/28441
            (EMPTY_ROOT_HASH, None)
        } else {
            (storage_hash, Some(Account { nonce, balance, bytecode_hash: code_hash.into() }))
        };

        Self { address, info, proof: account_proof, storage_root, storage_proofs }
    }
}

#[cfg(feature = "eip1186")]
impl From<alloy_rpc_types_eth::EIP1186AccountProofResponse> for AccountProof {
    fn from(proof: alloy_rpc_types_eth::EIP1186AccountProofResponse) -> Self {
        Self::from_eip1186_proof(proof)
    }
}

impl Default for AccountProof {
    fn default() -> Self {
        Self::new(Address::default())
    }
}

impl AccountProof {
    /// Create new account proof entity.
    pub const fn new(address: Address) -> Self {
        Self {
            address,
            info: None,
            proof: Vec::new(),
            storage_root: EMPTY_ROOT_HASH,
            storage_proofs: Vec::new(),
        }
    }

    /// Verify the storage proofs and account proof against the provided state root.
    pub fn verify(&self, root: B256) -> Result<(), ProofVerificationError> {
        // Verify storage proofs.
        for storage_proof in &self.storage_proofs {
            storage_proof.verify(self.storage_root)?;
        }

        // Verify the account proof.
        let expected = if self.info.is_none() && self.storage_root == EMPTY_ROOT_HASH {
            None
        } else {
            Some(alloy_rlp::encode(
                self.info.unwrap_or_default().into_trie_account(self.storage_root),
            ))
        };
        let nibbles = Nibbles::unpack(keccak256(self.address));
        verify_proof(root, nibbles, expected, &self.proof)
    }
}

/// The merkle proof with the relevant account info.
#[derive(Clone, PartialEq, Eq, Debug)]
pub struct DecodedAccountProof {
    /// The address associated with the account.
    pub address: Address,
    /// Account info.
    pub info: Option<Account>,
    /// Array of merkle trie nodes which starting from the root node and following the path of the
    /// hashed address as key.
    pub proof: Vec<TrieNode>,
    /// The storage trie root.
    pub storage_root: B256,
    /// Array of storage proofs as requested.
    pub storage_proofs: Vec<DecodedStorageProof>,
}

impl Default for DecodedAccountProof {
    fn default() -> Self {
        Self::new(Address::default())
    }
}

impl DecodedAccountProof {
    /// Create new account proof entity.
    pub const fn new(address: Address) -> Self {
        Self {
            address,
            info: None,
            proof: Vec::new(),
            storage_root: EMPTY_ROOT_HASH,
            storage_proofs: Vec::new(),
        }
    }
}

/// The merkle proof of the storage entry.
#[derive(Clone, PartialEq, Eq, Default, Debug)]
#[cfg_attr(any(test, feature = "serde"), derive(serde::Serialize, serde::Deserialize))]
pub struct StorageProof {
    /// The raw storage key.
    pub key: B256,
    /// The hashed storage key nibbles.
    pub nibbles: Nibbles,
    /// The storage value.
    pub value: U256,
    /// Array of rlp-serialized merkle trie nodes which starting from the storage root node and
    /// following the path of the hashed storage slot as key.
    pub proof: Vec<Bytes>,
}

impl StorageProof {
    /// Create new storage proof from the storage slot.
    pub fn new(key: B256) -> Self {
        let nibbles = Nibbles::unpack(keccak256(key));
        Self { key, nibbles, ..Default::default() }
    }

    /// Create new storage proof from the storage slot and its pre-hashed image.
    pub fn new_with_hashed(key: B256, hashed_key: B256) -> Self {
        Self { key, nibbles: Nibbles::unpack(hashed_key), ..Default::default() }
    }

    /// Create new storage proof from the storage slot and its pre-hashed image.
    pub fn new_with_nibbles(key: B256, nibbles: Nibbles) -> Self {
        Self { key, nibbles, ..Default::default() }
    }

    /// Set proof nodes on storage proof.
    pub fn with_proof(mut self, proof: Vec<Bytes>) -> Self {
        self.proof = proof;
        self
    }

    /// Verify the proof against the provided storage root.
    pub fn verify(&self, root: B256) -> Result<(), ProofVerificationError> {
        let expected =
            if self.value.is_zero() { None } else { Some(encode_fixed_size(&self.value).to_vec()) };
        verify_proof(root, self.nibbles, expected, &self.proof)
    }
}

#[cfg(feature = "eip1186")]
impl StorageProof {
    /// Convert into an EIP-1186 storage proof
    pub fn into_eip1186_proof(
        self,
        slot: alloy_serde::JsonStorageKey,
    ) -> alloy_rpc_types_eth::EIP1186StorageProof {
        alloy_rpc_types_eth::EIP1186StorageProof {
            key: slot,
            value: self.value,
            proof: normalize_eip1186_empty_trie_proof(self.proof),
        }
    }

    /// Convert from an
    /// [`EIP1186StorageProof`](alloy_rpc_types_eth::EIP1186StorageProof)
    ///
    /// This is the inverse of [`Self::into_eip1186_proof`].
    pub fn from_eip1186_proof(storage_proof: alloy_rpc_types_eth::EIP1186StorageProof) -> Self {
        Self {
            value: storage_proof.value,
            proof: storage_proof.proof,
            ..Self::new(storage_proof.key.as_b256())
        }
    }
}

#[cfg(feature = "eip1186")]
impl From<alloy_rpc_types_eth::EIP1186StorageProof> for StorageProof {
    fn from(proof: alloy_rpc_types_eth::EIP1186StorageProof) -> Self {
        Self::from_eip1186_proof(proof)
    }
}

/// The merkle proof of the storage entry, using decoded proofs.
#[derive(Clone, PartialEq, Eq, Default, Debug)]
pub struct DecodedStorageProof {
    /// The raw storage key.
    pub key: B256,
    /// The hashed storage key nibbles.
    pub nibbles: Nibbles,
    /// The storage value.
    pub value: U256,
    /// Array of merkle trie nodes which starting from the storage root node and following the path
    /// of the hashed storage slot as key.
    pub proof: Vec<TrieNode>,
}

impl DecodedStorageProof {
    /// Create new storage proof from the storage slot.
    pub fn new(key: B256) -> Self {
        let nibbles = Nibbles::unpack(keccak256(key));
        Self { key, nibbles, ..Default::default() }
    }

    /// Create new storage proof from the storage slot and its pre-hashed image.
    pub fn new_with_hashed(key: B256, hashed_key: B256) -> Self {
        Self { key, nibbles: Nibbles::unpack(hashed_key), ..Default::default() }
    }

    /// Create new storage proof from the storage slot and its pre-hashed image.
    pub fn new_with_nibbles(key: B256, nibbles: Nibbles) -> Self {
        Self { key, nibbles, ..Default::default() }
    }

    /// Set proof nodes on storage proof.
    pub fn with_proof(mut self, proof: Vec<TrieNode>) -> Self {
        self.proof = proof;
        self
    }
}

/// Implementation of hasher using our keccak256 hashing function
/// for compatibility with `triehash` crate.
#[cfg(any(test, feature = "test-utils"))]
pub mod triehash {
    use alloy_primitives::{keccak256, B256};
    use alloy_rlp::RlpEncodable;
    use hash_db::Hasher;
    use plain_hasher::PlainHasher;

    /// A [Hasher] that calculates a keccak256 hash of the given data.
    #[derive(Default, Debug, Clone, PartialEq, Eq, RlpEncodable)]
    #[non_exhaustive]
    pub struct KeccakHasher;

    #[cfg(any(test, feature = "test-utils"))]
    impl Hasher for KeccakHasher {
        type Out = B256;
        type StdHasher = PlainHasher;

        const LENGTH: usize = 32;

        fn hash(x: &[u8]) -> Self::Out {
            keccak256(x)
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use alloy_trie::{
        nodes::{BranchNode, LeafNode, RlpNode},
        TrieMask,
    };

    #[test]
    fn witness_nodes_are_depth_first_ordered() {
        fn insert_node(witness: &mut B256Map<Bytes>, node: impl alloy_rlp::Encodable) -> RlpNode {
            let encoded = alloy_rlp::encode(node);
            witness.insert(keccak256(&encoded), encoded.clone().into());
            RlpNode::from_rlp(&encoded)
        }

        let mut witness = B256Map::default();
        let leaf_key = Nibbles::from_nibbles([0; 63]);

        let storage_leaf_0 = insert_node(
            &mut witness,
            LeafNode::new(leaf_key, encode_fixed_size(&U256::from(1)).to_vec()),
        );
        let storage_leaf_1 = insert_node(
            &mut witness,
            LeafNode::new(leaf_key, encode_fixed_size(&U256::from(2)).to_vec()),
        );
        let storage_root = insert_node(
            &mut witness,
            BranchNode::new(vec![storage_leaf_0, storage_leaf_1], TrieMask::new(0b11)),
        );

        let account_leaf_0 = insert_node(
            &mut witness,
            LeafNode::new(
                leaf_key,
                alloy_rlp::encode(TrieAccount {
                    storage_root: storage_root.as_hash().expect("storage root is hashed"),
                    ..Default::default()
                }),
            ),
        );
        let account_leaf_1 = insert_node(
            &mut witness,
            LeafNode::new(leaf_key, alloy_rlp::encode(TrieAccount::default())),
        );
        let state_root = insert_node(
            &mut witness,
            BranchNode::new(vec![account_leaf_0, account_leaf_1], TrieMask::new(0b11)),
        )
        .as_hash()
        .expect("state root is hashed");

        let proof = DecodedMultiProofV2::from_witness(state_root, &witness).unwrap();
        let expected_paths =
            [Nibbles::from_nibbles([0]), Nibbles::from_nibbles([1]), Nibbles::default()];

        assert_eq!(
            proof.account_proofs.iter().map(|node| node.path).collect::<Vec<_>>(),
            expected_paths
        );
        assert_eq!(
            proof.storage_proofs[&B256::ZERO].iter().map(|node| node.path).collect::<Vec<_>>(),
            expected_paths
        );
    }

    #[test]
    fn test_multiproof_extend_account_proofs() {
        let mut proof1 = MultiProof::default();
        let mut proof2 = MultiProof::default();

        let addr1 = B256::random();
        let addr2 = B256::random();

        proof1.account_subtree.insert(
            Nibbles::unpack(addr1),
            alloy_rlp::encode_fixed_size(&U256::from(42)).to_vec().into(),
        );
        proof2.account_subtree.insert(
            Nibbles::unpack(addr2),
            alloy_rlp::encode_fixed_size(&U256::from(43)).to_vec().into(),
        );

        proof1.extend(proof2);

        assert!(proof1.account_subtree.contains_key(&Nibbles::unpack(addr1)));
        assert!(proof1.account_subtree.contains_key(&Nibbles::unpack(addr2)));
    }

    #[test]
    fn test_multiproof_extend_storage_proofs() {
        let mut proof1 = MultiProof::default();
        let mut proof2 = MultiProof::default();

        let addr = B256::random();
        let root = B256::random();

        let mut subtree1 = ProofNodes::default();
        subtree1.insert(
            Nibbles::from_nibbles(vec![0]),
            alloy_rlp::encode_fixed_size(&U256::from(42)).to_vec().into(),
        );
        proof1.storages.insert(
            addr,
            StorageMultiProof {
                root,
                subtree: subtree1,
                branch_node_masks: BranchNodeMasksMap::default(),
            },
        );

        let mut subtree2 = ProofNodes::default();
        subtree2.insert(
            Nibbles::from_nibbles(vec![1]),
            alloy_rlp::encode_fixed_size(&U256::from(43)).to_vec().into(),
        );
        proof2.storages.insert(
            addr,
            StorageMultiProof {
                root,
                subtree: subtree2,
                branch_node_masks: BranchNodeMasksMap::default(),
            },
        );

        proof1.extend(proof2);

        let storage = proof1.storages.get(&addr).unwrap();
        assert_eq!(storage.root, root);
        assert!(storage.subtree.contains_key(&Nibbles::from_nibbles(vec![0])));
        assert!(storage.subtree.contains_key(&Nibbles::from_nibbles(vec![1])));
    }

    #[test]
    fn test_multi_proof_retain_difference() {
        let mut empty = MultiProofTargets::default();
        empty.retain_difference(&Default::default());
        assert!(empty.is_empty());

        let targets = MultiProofTargets::accounts((0..10).map(B256::with_last_byte));

        let mut diffed = targets.clone();
        diffed.retain_difference(&MultiProofTargets::account(B256::with_last_byte(11)));
        assert_eq!(diffed, targets);

        diffed.retain_difference(&MultiProofTargets::accounts((0..5).map(B256::with_last_byte)));
        assert_eq!(diffed, MultiProofTargets::accounts((5..10).map(B256::with_last_byte)));

        diffed.retain_difference(&targets);
        assert!(diffed.is_empty());

        let mut targets = MultiProofTargets::default();
        let (account1, account2, account3) =
            (1..=3).map(B256::with_last_byte).collect_tuple().unwrap();
        let account2_slots = (1..5).map(B256::with_last_byte).collect::<B256Set>();
        targets.insert(account1, B256Set::from_iter([B256::with_last_byte(1)]));
        targets.insert(account2, account2_slots.clone());
        targets.insert(account3, B256Set::from_iter([B256::with_last_byte(1)]));

        let mut diffed = targets.clone();
        diffed.retain_difference(&MultiProofTargets::accounts((1..=3).map(B256::with_last_byte)));
        assert_eq!(diffed, targets);

        // remove last 3 slots for account 2
        let mut account2_slots_expected_len = account2_slots.len();
        for slot in account2_slots.iter().skip(1) {
            diffed.retain_difference(&MultiProofTargets::account_with_slots(account2, [*slot]));
            account2_slots_expected_len -= 1;
            assert_eq!(
                diffed.get(&account2).map(|slots| slots.len()),
                Some(account2_slots_expected_len)
            );
        }

        diffed.retain_difference(&targets);
        assert!(diffed.is_empty());
    }

    #[test]
    fn test_multi_proof_retain_difference_no_overlap() {
        let mut targets = MultiProofTargets::default();

        // populate some targets
        let (addr1, addr2) = (B256::random(), B256::random());
        let (slot1, slot2) = (B256::random(), B256::random());
        targets.insert(addr1, std::iter::once(slot1).collect());
        targets.insert(addr2, std::iter::once(slot2).collect());

        let mut retained = targets.clone();
        retained.retain_difference(&Default::default());
        assert_eq!(retained, targets);

        // add a different addr and slot to fetched proof targets
        let mut other_targets = MultiProofTargets::default();
        let addr3 = B256::random();
        let slot3 = B256::random();
        other_targets.insert(addr3, B256Set::from_iter([slot3]));

        // check that the prefetch proof targets are the same because the fetched proof targets
        // don't overlap with the prefetch targets
        let mut retained = targets.clone();
        retained.retain_difference(&other_targets);
        assert_eq!(retained, targets);
    }

    #[test]
    fn test_get_prefetch_proof_targets_remove_subset() {
        // populate some targets
        let mut targets = MultiProofTargets::default();
        let (addr1, addr2) = (B256::random(), B256::random());
        let (slot1, slot2) = (B256::random(), B256::random());
        targets.insert(addr1, B256Set::from_iter([slot1]));
        targets.insert(addr2, B256Set::from_iter([slot2]));

        // add a subset of the first target to other proof targets
        let other_targets = MultiProofTargets::account_with_slots(addr1, [slot1]);

        let mut retained = targets.clone();
        retained.retain_difference(&other_targets);

        // check that the prefetch proof targets do not include the subset
        assert_eq!(retained.len(), 1);
        assert!(!retained.contains_key(&addr1));
        assert!(retained.contains_key(&addr2));

        // now add one more slot to the prefetch targets
        let slot3 = B256::random();
        targets.get_mut(&addr1).unwrap().insert(slot3);

        let mut retained = targets.clone();
        retained.retain_difference(&other_targets);

        // check that the prefetch proof targets do not include the subset
        // but include the new slot
        assert_eq!(retained.len(), 2);
        assert!(retained.contains_key(&addr1));
        assert_eq!(retained.get(&addr1), Some(&B256Set::from_iter([slot3])));
        assert!(retained.contains_key(&addr2));
        assert_eq!(retained.get(&addr2), Some(&B256Set::from_iter([slot2])));
    }

    #[test]
    #[cfg(feature = "eip1186")]
    fn eip_1186_roundtrip() {
        let mut acc = AccountProof {
            address: Address::random(),
            info: Some(
                // non-empty account
                Account { nonce: 100, balance: U256::ZERO, bytecode_hash: Some(KECCAK_EMPTY) },
            ),
            proof: vec![],
            storage_root: B256::ZERO,
            storage_proofs: vec![],
        };

        let rpc_proof = acc.clone().into_eip1186_response(Vec::new());
        let inverse: AccountProof = rpc_proof.into();
        assert_eq!(acc, inverse);

        // make account empty
        acc.info.as_mut().unwrap().nonce = 0;
        let rpc_proof = acc.clone().into_eip1186_response(Vec::new());
        let inverse: AccountProof = rpc_proof.into();
        acc.info.take();
        acc.storage_root = EMPTY_ROOT_HASH;
        assert_eq!(acc, inverse);
    }

    #[test]
    #[cfg(feature = "eip1186")]
    fn from_eip1186_proof_accepts_geth_zero_hashes() {
        // geth (since v1.13.4) returns B256::ZERO for codeHash and storageHash
        // in exclusion proofs for non-existent accounts, instead of
        // KECCAK_EMPTY / EMPTY_ROOT_HASH. Verify that from_eip1186_proof
        // correctly recognizes this format as a non-existent account.
        let geth_proof = alloy_rpc_types_eth::EIP1186AccountProofResponse {
            address: Address::random(),
            balance: U256::ZERO,
            code_hash: B256::ZERO,
            nonce: 0,
            storage_hash: B256::ZERO,
            account_proof: vec![],
            storage_proof: vec![],
        };

        let acc: AccountProof = geth_proof.into();
        // Should be interpreted as a non-existent account (info = None)
        assert!(acc.info.is_none());
        assert_eq!(acc.storage_root, EMPTY_ROOT_HASH);
    }

    #[test]
    #[cfg(feature = "eip1186")]
    fn from_eip1186_proof_accepts_empty_hashes() {
        let proof = alloy_rpc_types_eth::EIP1186AccountProofResponse {
            address: Address::random(),
            balance: U256::ZERO,
            code_hash: KECCAK_EMPTY,
            nonce: 0,
            storage_hash: EMPTY_ROOT_HASH,
            account_proof: vec![],
            storage_proof: vec![],
        };

        let acc: AccountProof = proof.into();
        assert!(acc.info.is_none());
        assert_eq!(acc.storage_root, EMPTY_ROOT_HASH);
    }

    #[test]
    #[cfg(feature = "eip1186")]
    fn into_eip1186_response_zero_empty_account() {
        // Non-existent account (info = None)
        let acc = AccountProof {
            address: Address::random(),
            info: None,
            proof: vec![],
            storage_root: EMPTY_ROOT_HASH,
            storage_proofs: vec![],
        };

        // Default behavior: KECCAK_EMPTY / EMPTY_ROOT_HASH
        let rpc_default = acc.clone().into_eip1186_response(Vec::new());
        assert_eq!(rpc_default.code_hash, KECCAK_EMPTY);
        assert_eq!(rpc_default.storage_hash, EMPTY_ROOT_HASH);

        // zero_empty_account = false: same as default
        let rpc_compat_off = acc.clone().into_eip1186_response_with(Vec::new(), false);
        assert_eq!(rpc_compat_off.code_hash, KECCAK_EMPTY);
        assert_eq!(rpc_compat_off.storage_hash, EMPTY_ROOT_HASH);

        // zero_empty_account = true: B256::ZERO (geth-compat)
        let rpc_compat_on = acc.into_eip1186_response_with(Vec::new(), true);
        assert_eq!(rpc_compat_on.code_hash, B256::ZERO);
        assert_eq!(rpc_compat_on.storage_hash, B256::ZERO);

        // Existing account should NOT be affected by zero_empty_account
        let existing_acc = AccountProof {
            address: Address::random(),
            info: Some(Account {
                nonce: 42,
                balance: U256::from(100),
                bytecode_hash: Some(KECCAK_EMPTY),
            }),
            proof: vec![],
            storage_root: B256::random(),
            storage_proofs: vec![],
        };
        let rpc_existing = existing_acc.clone().into_eip1186_response_with(Vec::new(), true);
        assert_eq!(rpc_existing.code_hash, KECCAK_EMPTY);
        assert_eq!(rpc_existing.storage_hash, existing_acc.storage_root);
    }

    #[test]
    fn test_multiproof_targets_chunking_length() {
        let mut targets = MultiProofTargets::default();
        targets.insert(B256::with_last_byte(1), B256Set::default());
        targets.insert(
            B256::with_last_byte(2),
            B256Set::from_iter([B256::with_last_byte(10), B256::with_last_byte(20)]),
        );
        targets.insert(
            B256::with_last_byte(3),
            B256Set::from_iter([
                B256::with_last_byte(30),
                B256::with_last_byte(31),
                B256::with_last_byte(32),
            ]),
        );

        let chunking_length = targets.chunking_length();
        for size in 1..=targets.clone().chunks(1).count() {
            let chunk_count = targets.clone().chunks(size).count();
            let expected_count = chunking_length.div_ceil(size);
            assert_eq!(
                chunk_count, expected_count,
                "chunking_length: {}, size: {}",
                chunking_length, size
            );
        }
    }

    #[test]
    fn test_nonempty_storage_trie_returns_nonempty_proof() {
        let slot = B256::with_last_byte(1);
        let nibbles = Nibbles::unpack(keccak256(slot));
        let value = U256::from(999);
        let leaf = alloy_trie::nodes::LeafNode::new(nibbles, encode_fixed_size(&value).to_vec());
        let mut encoded = vec![];
        alloy_rlp::Encodable::encode(&leaf, &mut encoded);

        let mut subtree = ProofNodes::default();
        subtree.insert(nibbles, encoded.into());

        let multiproof = StorageMultiProof {
            root: B256::with_last_byte(0xFF),
            subtree,
            branch_node_masks: BranchNodeMasksMap::default(),
        };

        let proof = multiproof.storage_proof(slot).unwrap();
        assert!(!proof.proof.is_empty(), "non-empty trie must return non-empty proof");
        assert_eq!(proof.value, value);
    }

    #[cfg(feature = "eip1186")]
    #[test]
    fn eip1186_response_normalizes_empty_trie_proof() {
        let slot = B256::with_last_byte(1);
        let sentinel = || vec![Bytes::from([EMPTY_STRING_CODE])];

        // Empty account trie + empty storage trie: both proofs are the lone `0x80` sentinel.
        let account = AccountProof {
            address: Address::ZERO,
            info: None,
            proof: sentinel(),
            storage_root: EMPTY_ROOT_HASH,
            storage_proofs: vec![StorageProof::new(slot).with_proof(sentinel())],
        };

        let resp = account.into_eip1186_response(vec![alloy_serde::JsonStorageKey::from(slot)]);

        assert!(
            resp.account_proof.is_empty(),
            "empty account trie must yield empty account_proof, got {:?}",
            resp.account_proof
        );
        assert_eq!(resp.storage_proof.len(), 1);
        assert!(
            resp.storage_proof[0].proof.is_empty(),
            "empty storage trie must yield empty storage proof, got {:?}",
            resp.storage_proof[0].proof
        );
    }

    #[cfg(feature = "eip1186")]
    #[test]
    fn eip1186_response_keeps_nonempty_proof() {
        // A real (non-empty) proof must pass through unchanged: multiple nodes, and a single
        // node that is not the `0x80` sentinel.
        let multi = vec![Bytes::from([0x01, 0x02]), Bytes::from([0x03])];
        let single_non_sentinel = vec![Bytes::from([0xf8, 0x44])];

        let account = AccountProof {
            address: Address::ZERO,
            info: None,
            proof: multi.clone(),
            storage_root: EMPTY_ROOT_HASH,
            storage_proofs: vec![
                StorageProof::new(B256::with_last_byte(1)).with_proof(single_non_sentinel.clone())
            ],
        };

        let resp = account.into_eip1186_response(vec![alloy_serde::JsonStorageKey::from(
            B256::with_last_byte(1),
        )]);

        assert_eq!(resp.account_proof, multi);
        assert_eq!(resp.storage_proof[0].proof, single_non_sentinel);
    }
}