bugfix: reverse merkle path to match other structures

The store builds the path from root to leaf, this updates the code to
return a path from leaf to root, as it is done by the other structures.

This also added custom error for missing root.
This commit is contained in:
Victor Lopez
2023-03-16 19:50:59 +01:00
parent 867b772d9a
commit 8cb245dc1f
3 changed files with 555 additions and 243 deletions

361
src/merkle/store/mod.rs Normal file
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@@ -0,0 +1,361 @@
//! An in-memory data store for Merkle-lized data
//!
//! This is a in memory data store for Merkle trees, this store allows all the nodes of a tree
//! (leaves or internal) to live as long as necessary and without duplication, this allows the
//! implementation of efficient persistent data structures
use super::{
BTreeMap, BTreeSet, EmptySubtreeRoots, MerkleError, MerklePath, MerklePathSet, MerkleTree,
NodeIndex, Rpo256, RpoDigest, SimpleSmt, Vec, Word,
};
#[cfg(test)]
mod tests;
#[derive(Debug, Default, Copy, Clone, Eq, PartialEq)]
pub struct Node {
left: RpoDigest,
right: RpoDigest,
}
#[derive(Debug, Clone, Eq, PartialEq)]
pub struct MerkleStore {
nodes: BTreeMap<RpoDigest, Node>,
}
impl Default for MerkleStore {
fn default() -> Self {
Self::new()
}
}
impl MerkleStore {
// CONSTRUCTORS
// --------------------------------------------------------------------------------------------
/// Creates an empty `MerkleStore` instance.
pub fn new() -> MerkleStore {
// pre-populate the store with the empty hashes
let subtrees = EmptySubtreeRoots::empty_hashes(64);
let nodes = subtrees
.iter()
.copied()
.zip(subtrees.iter().skip(1).copied())
.map(|(child, parent)| {
(
parent,
Node {
left: child,
right: child,
},
)
})
.collect();
MerkleStore { nodes }
}
/// Appends the provided merkle tree represented by its `leaves` to the set.
pub fn with_merkle_tree<I>(mut self, leaves: I) -> Result<Self, MerkleError>
where
I: IntoIterator<Item = Word>,
{
self.add_merkle_tree(leaves)?;
Ok(self)
}
/// Appends the provided sparse merkle tree represented by its `entries` to the set.
pub fn with_sparse_merkle_tree<R, I>(mut self, entries: R) -> Result<Self, MerkleError>
where
R: IntoIterator<IntoIter = I>,
I: Iterator<Item = (u64, Word)> + ExactSizeIterator,
{
self.add_sparse_merkle_tree(entries)?;
Ok(self)
}
/// Appends the provided merkle path set.
pub fn with_merkle_path(
mut self,
index_value: u64,
node: Word,
path: MerklePath,
) -> Result<Self, MerkleError> {
self.add_merkle_path(index_value, node, path)?;
Ok(self)
}
// PUBLIC ACCESSORS
// --------------------------------------------------------------------------------------------
/// Returns the node at `index` rooted on the tree `root`.
///
/// # Errors
///
/// This method can return the following errors:
/// - `RootNotInStore` if the `root` is not present in the storage.
/// - `NodeNotInStore` if a node needed to traverse from `root` to `index` is not present in the store.
pub fn get_node(&self, root: Word, index: NodeIndex) -> Result<Word, MerkleError> {
let mut hash: RpoDigest = root.into();
// corner case: check the root is in the storage when called with index `NodeIndex::root()`
self.nodes
.get(&hash)
.ok_or(MerkleError::RootNotInStore(hash.into()))?;
for bit in index.bit_iterator().rev() {
let node = self
.nodes
.get(&hash)
.ok_or(MerkleError::NodeNotInStore(hash.into(), index))?;
hash = if bit { node.right } else { node.left }
}
Ok(hash.into())
}
/// Returns the node at the specified `index` and its opening to the `root`.
///
/// The path starts at the sibling of the target leaf.
///
/// # Errors
///
/// This method can return the following errors:
/// - `RootNotInStore` if the `root` is not present in the storage.
/// - `NodeNotInStore` if a node needed to traverse from `root` to `index` is not present in the store.
pub fn get_path(
&self,
root: Word,
index: NodeIndex,
) -> Result<(Word, MerklePath), MerkleError> {
let mut hash: RpoDigest = root.into();
let mut path = Vec::with_capacity(index.depth().into());
// corner case: check the root is in the storage when called with index `NodeIndex::root()`
self.nodes
.get(&hash)
.ok_or(MerkleError::RootNotInStore(hash.into()))?;
for bit in index.bit_iterator().rev() {
let node = self
.nodes
.get(&hash)
.ok_or(MerkleError::NodeNotInStore(hash.into(), index))?;
hash = if bit {
path.push(node.left.into());
node.right
} else {
path.push(node.right.into());
node.left
}
}
path.reverse();
Ok((hash.into(), MerklePath::new(path)))
}
// STATE MUTATORS
// --------------------------------------------------------------------------------------------
/// Adds all the nodes of a Merkle tree represented by `leaves`.
///
/// This will instantiate a Merkle tree using `leaves` and include all the nodes into the
/// storage.
///
/// # Errors
///
/// This method may return the following errors:
/// - `DepthTooSmall` if leaves is empty or contains only 1 element
/// - `NumLeavesNotPowerOfTwo` if the number of leaves is not a power-of-two
pub fn add_merkle_tree<I>(&mut self, leaves: I) -> Result<Word, MerkleError>
where
I: IntoIterator<Item = Word>,
{
let leaves: Vec<_> = leaves.into_iter().collect();
if leaves.len() < 2 {
return Err(MerkleError::DepthTooSmall(leaves.len() as u8));
}
let layers = leaves.len().ilog2();
let tree = MerkleTree::new(leaves)?;
let mut depth = 0;
let mut parent_offset = 1;
let mut child_offset = 2;
while depth < layers {
let layer_size = 1usize << depth;
for _ in 0..layer_size {
// merkle tree is using level form representation, so left and right siblings are
// next to each other
let left = tree.nodes[child_offset];
let right = tree.nodes[child_offset + 1];
self.nodes.insert(
tree.nodes[parent_offset].into(),
Node {
left: left.into(),
right: right.into(),
},
);
parent_offset += 1;
child_offset += 2;
}
depth += 1;
}
Ok(tree.nodes[1])
}
/// Adds all the nodes of a Sparse Merkle tree represented by `entries`.
///
/// This will instantiate a Sparse Merkle tree using `entries` and include all the nodes into
/// the storage.
///
/// # Errors
///
/// This will return `InvalidEntriesCount` if the length of `entries` is not `63`.
pub fn add_sparse_merkle_tree<R, I>(&mut self, entries: R) -> Result<Word, MerkleError>
where
R: IntoIterator<IntoIter = I>,
I: Iterator<Item = (u64, Word)> + ExactSizeIterator,
{
let smt = SimpleSmt::new(SimpleSmt::MAX_DEPTH)?.with_leaves(entries)?;
for branch in smt.store.branches.values() {
let parent = Rpo256::merge(&[branch.left, branch.right]);
self.nodes.insert(
parent,
Node {
left: branch.left,
right: branch.right,
},
);
}
Ok(smt.root())
}
/// Adds all the nodes of a Merkle path represented by `path`.
///
/// This will compute the sibling elements determined by the Merkle `path` and `node`, and
/// include all the nodes into the storage.
pub fn add_merkle_path(
&mut self,
index_value: u64,
node: Word,
path: MerklePath,
) -> Result<Word, MerkleError> {
let mut node = node;
let mut index = NodeIndex::new(self.nodes.len() as u8, index_value);
for sibling in path {
let (left, right) = match index.is_value_odd() {
true => (sibling, node),
false => (node, sibling),
};
let parent = Rpo256::merge(&[left.into(), right.into()]);
self.nodes.insert(
parent,
Node {
left: left.into(),
right: right.into(),
},
);
index.move_up();
node = parent.into();
}
Ok(node)
}
/// Adds all the nodes of multiple Merkle paths into the store.
///
/// This will compute the sibling elements for each Merkle `path` and include all the nodes
/// into the storage.
///
/// # Errors
///
/// Every path must resolve to the same root, otherwise this will return an `ConflictingRoots`
/// error.
pub fn add_merkle_paths<I>(&mut self, paths: I) -> Result<Word, MerkleError>
where
I: IntoIterator<Item = (u64, Word, MerklePath)>,
{
let paths: Vec<(u64, Word, MerklePath)> = paths.into_iter().collect();
let roots: BTreeSet<RpoDigest> = paths
.iter()
.map(|(index, node, path)| path.compute_root(*index, *node).into())
.collect();
if roots.len() != 1 {
return Err(MerkleError::ConflictingRoots(
roots.iter().map(|v| Word::from(*v)).collect(),
));
}
for (index_value, node, path) in paths {
self.add_merkle_path(index_value, node, path)?;
}
Ok(roots.iter().next().unwrap().into())
}
/// Appends the provided [MerklePathSet] into the store.
pub fn add_merkle_path_set(&mut self, path_set: &MerklePathSet) -> Result<Word, MerkleError> {
let root = path_set.root();
path_set.indexes().try_fold(root, |_, index| {
let node = path_set.get_node(index)?;
let path = path_set.get_path(index)?;
self.add_merkle_path(index.value(), node, path)
})
}
/// Sets a node to `value`.
///
/// # Errors
///
/// This method can return the following errors:
/// - `RootNotInStore` if the `root` is not present in the storage.
/// - `NodeNotInStore` if a node needed to traverse from `root` to `index` is not present in the store.
pub fn set_node(
&mut self,
root: Word,
index: NodeIndex,
value: Word,
) -> Result<Word, MerkleError> {
let result = self.get_path(root, index)?;
if result.0 != value {
self.add_merkle_path(index.value(), value, result.1)
} else {
Ok(root)
}
}
pub fn merge_roots(&mut self, root1: Word, root2: Word) -> Result<Word, MerkleError> {
let root1: RpoDigest = root1.into();
let root2: RpoDigest = root2.into();
if !self.nodes.contains_key(&root1) {
Err(MerkleError::NodeNotInStore(
root1.into(),
NodeIndex::new(0, 0),
))
} else if !self.nodes.contains_key(&root1) {
Err(MerkleError::NodeNotInStore(
root2.into(),
NodeIndex::new(0, 0),
))
} else {
let parent: Word = Rpo256::merge(&[root1, root2]).into();
self.nodes.insert(
parent.into(),
Node {
left: root1,
right: root2,
},
);
Ok(parent)
}
}
}

497
src/merkle/store/tests.rs Normal file
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use super::*;
use crate::{
hash::rpo::Rpo256,
merkle::{int_to_node, MerklePathSet},
Felt, Word,
};
const KEYS4: [u64; 4] = [0, 1, 2, 3];
const LEAVES4: [Word; 4] = [
int_to_node(1),
int_to_node(2),
int_to_node(3),
int_to_node(4),
];
#[test]
fn test_root_not_in_storage() -> Result<(), MerkleError> {
let mtree = MerkleTree::new(LEAVES4.to_vec())?;
let store = MerkleStore::default().with_merkle_tree(LEAVES4)?;
assert_eq!(
store.get_node(LEAVES4[0], NodeIndex::new(mtree.depth(), 0)),
Err(MerkleError::RootNotInStore(LEAVES4[0])),
"Leaf 0 is not a root"
);
assert_eq!(
store.get_path(LEAVES4[0], NodeIndex::new(mtree.depth(), 0)),
Err(MerkleError::RootNotInStore(LEAVES4[0])),
"Leaf 0 is not a root"
);
Ok(())
}
#[test]
fn test_merkle_tree() -> Result<(), MerkleError> {
let mut store = MerkleStore::default();
let mtree = MerkleTree::new(LEAVES4.to_vec())?;
store.add_merkle_tree(LEAVES4.to_vec())?;
// STORE LEAVES ARE CORRECT ==============================================================
// checks the leaves in the store corresponds to the expected values
assert_eq!(
store.get_node(mtree.root(), NodeIndex::new(mtree.depth(), 0)),
Ok(LEAVES4[0]),
"node 0 must be in the tree"
);
assert_eq!(
store.get_node(mtree.root(), NodeIndex::new(mtree.depth(), 1)),
Ok(LEAVES4[1]),
"node 1 must be in the tree"
);
assert_eq!(
store.get_node(mtree.root(), NodeIndex::new(mtree.depth(), 2)),
Ok(LEAVES4[2]),
"node 2 must be in the tree"
);
assert_eq!(
store.get_node(mtree.root(), NodeIndex::new(mtree.depth(), 3)),
Ok(LEAVES4[3]),
"node 3 must be in the tree"
);
// STORE LEAVES MATCH TREE ===============================================================
// sanity check the values returned by the store and the tree
assert_eq!(
mtree.get_node(NodeIndex::new(mtree.depth(), 0)),
store.get_node(mtree.root(), NodeIndex::new(mtree.depth(), 0)),
"node 0 must be the same for both MerkleTree and MerkleStore"
);
assert_eq!(
mtree.get_node(NodeIndex::new(mtree.depth(), 1)),
store.get_node(mtree.root(), NodeIndex::new(mtree.depth(), 1)),
"node 1 must be the same for both MerkleTree and MerkleStore"
);
assert_eq!(
mtree.get_node(NodeIndex::new(mtree.depth(), 2)),
store.get_node(mtree.root(), NodeIndex::new(mtree.depth(), 2)),
"node 2 must be the same for both MerkleTree and MerkleStore"
);
assert_eq!(
mtree.get_node(NodeIndex::new(mtree.depth(), 3)),
store.get_node(mtree.root(), NodeIndex::new(mtree.depth(), 3)),
"node 3 must be the same for both MerkleTree and MerkleStore"
);
// STORE MERKLE PATH MATCHS ==============================================================
// assert the merkle path returned by the store is the same as the one in the tree
let result = store
.get_path(mtree.root(), NodeIndex::new(mtree.depth(), 0))
.unwrap();
assert_eq!(
LEAVES4[0], result.0,
"Value for merkle path at index 0 must match leaf value"
);
assert_eq!(
mtree.get_path(NodeIndex::new(mtree.depth(), 0)),
Ok(result.1),
"merkle path for index 0 must be the same for the MerkleTree and MerkleStore"
);
let result = store
.get_path(mtree.root(), NodeIndex::new(mtree.depth(), 1))
.unwrap();
assert_eq!(
LEAVES4[1], result.0,
"Value for merkle path at index 0 must match leaf value"
);
assert_eq!(
mtree.get_path(NodeIndex::new(mtree.depth(), 1)),
Ok(result.1),
"merkle path for index 1 must be the same for the MerkleTree and MerkleStore"
);
let result = store
.get_path(mtree.root(), NodeIndex::new(mtree.depth(), 2))
.unwrap();
assert_eq!(
LEAVES4[2], result.0,
"Value for merkle path at index 0 must match leaf value"
);
assert_eq!(
mtree.get_path(NodeIndex::new(mtree.depth(), 2)),
Ok(result.1),
"merkle path for index 0 must be the same for the MerkleTree and MerkleStore"
);
let result = store
.get_path(mtree.root(), NodeIndex::new(mtree.depth(), 3))
.unwrap();
assert_eq!(
LEAVES4[3], result.0,
"Value for merkle path at index 0 must match leaf value"
);
assert_eq!(
mtree.get_path(NodeIndex::new(mtree.depth(), 3)),
Ok(result.1),
"merkle path for index 0 must be the same for the MerkleTree and MerkleStore"
);
Ok(())
}
#[test]
fn test_get_invalid_node() {
let mut store = MerkleStore::default();
let mtree = MerkleTree::new(LEAVES4.to_vec()).expect("creating a merkle tree must work");
store
.add_merkle_tree(LEAVES4.to_vec())
.expect("adding a merkle tree to the store must work");
let _ = store.get_node(mtree.root(), NodeIndex::new(mtree.depth(), 3));
}
#[test]
fn test_add_sparse_merkle_tree_one_level() -> Result<(), MerkleError> {
let mut store = MerkleStore::default();
let keys2: [u64; 2] = [0, 1];
let leaves2: [Word; 2] = [int_to_node(1), int_to_node(2)];
store.add_sparse_merkle_tree(keys2.into_iter().zip(leaves2.into_iter()))?;
let smt = SimpleSmt::new(1)
.unwrap()
.with_leaves(keys2.into_iter().zip(leaves2.into_iter()))
.unwrap();
let idx = NodeIndex::new(1, 0);
assert_eq!(smt.get_node(&idx).unwrap(), leaves2[0]);
assert_eq!(
store.get_node(smt.root(), idx).unwrap(),
smt.get_node(&idx).unwrap()
);
let idx = NodeIndex::new(1, 1);
assert_eq!(smt.get_node(&idx).unwrap(), leaves2[1]);
assert_eq!(
store.get_node(smt.root(), idx).unwrap(),
smt.get_node(&idx).unwrap()
);
Ok(())
}
#[test]
fn test_sparse_merkle_tree() -> Result<(), MerkleError> {
let mut store = MerkleStore::default();
store.add_sparse_merkle_tree(KEYS4.into_iter().zip(LEAVES4.into_iter()))?;
let smt = SimpleSmt::new(SimpleSmt::MAX_DEPTH)
.unwrap()
.with_leaves(KEYS4.into_iter().zip(LEAVES4.into_iter()))
.unwrap();
// STORE LEAVES ARE CORRECT ==============================================================
// checks the leaves in the store corresponds to the expected values
assert_eq!(
store.get_node(smt.root(), NodeIndex::new(smt.depth(), 0)),
Ok(LEAVES4[0]),
"node 0 must be in the tree"
);
assert_eq!(
store.get_node(smt.root(), NodeIndex::new(smt.depth(), 1)),
Ok(LEAVES4[1]),
"node 1 must be in the tree"
);
assert_eq!(
store.get_node(smt.root(), NodeIndex::new(smt.depth(), 2)),
Ok(LEAVES4[2]),
"node 2 must be in the tree"
);
assert_eq!(
store.get_node(smt.root(), NodeIndex::new(smt.depth(), 3)),
Ok(LEAVES4[3]),
"node 3 must be in the tree"
);
// STORE LEAVES MATCH TREE ===============================================================
// sanity check the values returned by the store and the tree
assert_eq!(
smt.get_node(&NodeIndex::new(smt.depth(), 0)),
store.get_node(smt.root(), NodeIndex::new(smt.depth(), 0)),
"node 0 must be the same for both SparseMerkleTree and MerkleStore"
);
assert_eq!(
smt.get_node(&NodeIndex::new(smt.depth(), 1)),
store.get_node(smt.root(), NodeIndex::new(smt.depth(), 1)),
"node 1 must be the same for both SparseMerkleTree and MerkleStore"
);
assert_eq!(
smt.get_node(&NodeIndex::new(smt.depth(), 2)),
store.get_node(smt.root(), NodeIndex::new(smt.depth(), 2)),
"node 2 must be the same for both SparseMerkleTree and MerkleStore"
);
assert_eq!(
smt.get_node(&NodeIndex::new(smt.depth(), 3)),
store.get_node(smt.root(), NodeIndex::new(smt.depth(), 3)),
"node 3 must be the same for both SparseMerkleTree and MerkleStore"
);
// STORE MERKLE PATH MATCHS ==============================================================
// assert the merkle path returned by the store is the same as the one in the tree
let result = store
.get_path(smt.root(), NodeIndex::new(smt.depth(), 0))
.unwrap();
assert_eq!(
LEAVES4[0], result.0,
"Value for merkle path at index 0 must match leaf value"
);
assert_eq!(
smt.get_path(NodeIndex::new(smt.depth(), 0)),
Ok(result.1),
"merkle path for index 0 must be the same for the MerkleTree and MerkleStore"
);
let result = store
.get_path(smt.root(), NodeIndex::new(smt.depth(), 1))
.unwrap();
assert_eq!(
LEAVES4[1], result.0,
"Value for merkle path at index 0 must match leaf value"
);
assert_eq!(
smt.get_path(NodeIndex::new(smt.depth(), 1)),
Ok(result.1),
"merkle path for index 1 must be the same for the MerkleTree and MerkleStore"
);
let result = store
.get_path(smt.root(), NodeIndex::new(smt.depth(), 2))
.unwrap();
assert_eq!(
LEAVES4[2], result.0,
"Value for merkle path at index 0 must match leaf value"
);
assert_eq!(
smt.get_path(NodeIndex::new(smt.depth(), 2)),
Ok(result.1),
"merkle path for index 0 must be the same for the MerkleTree and MerkleStore"
);
let result = store
.get_path(smt.root(), NodeIndex::new(smt.depth(), 3))
.unwrap();
assert_eq!(
LEAVES4[3], result.0,
"Value for merkle path at index 0 must match leaf value"
);
assert_eq!(
smt.get_path(NodeIndex::new(smt.depth(), 3)),
Ok(result.1),
"merkle path for index 0 must be the same for the MerkleTree and MerkleStore"
);
Ok(())
}
#[test]
fn test_add_merkle_paths() -> Result<(), MerkleError> {
let mtree = MerkleTree::new(LEAVES4.to_vec())?;
let i0 = 0;
let p0 = mtree.get_path(NodeIndex::new(2, i0)).unwrap();
let i1 = 1;
let p1 = mtree.get_path(NodeIndex::new(2, i1)).unwrap();
let i2 = 2;
let p2 = mtree.get_path(NodeIndex::new(2, i2)).unwrap();
let i3 = 3;
let p3 = mtree.get_path(NodeIndex::new(2, i3)).unwrap();
let paths = [
(i0, LEAVES4[i0 as usize], p0),
(i1, LEAVES4[i1 as usize], p1),
(i2, LEAVES4[i2 as usize], p2),
(i3, LEAVES4[i3 as usize], p3),
];
let mut store = MerkleStore::default();
store
.add_merkle_paths(paths.clone())
.expect("the valid paths must work");
let depth = 3;
let set = MerklePathSet::new(depth).with_paths(paths).unwrap();
// STORE LEAVES ARE CORRECT ==============================================================
// checks the leaves in the store corresponds to the expected values
assert_eq!(
store.get_node(set.root(), NodeIndex::new(set.depth() - 1, 0)),
Ok(LEAVES4[0]),
"node 0 must be in the set"
);
assert_eq!(
store.get_node(set.root(), NodeIndex::new(set.depth() - 1, 1)),
Ok(LEAVES4[1]),
"node 1 must be in the set"
);
assert_eq!(
store.get_node(set.root(), NodeIndex::new(set.depth() - 1, 2)),
Ok(LEAVES4[2]),
"node 2 must be in the set"
);
assert_eq!(
store.get_node(set.root(), NodeIndex::new(set.depth() - 1, 3)),
Ok(LEAVES4[3]),
"node 3 must be in the set"
);
// STORE LEAVES MATCH SET ================================================================
// sanity check the values returned by the store and the set
assert_eq!(
set.get_node(NodeIndex::new(set.depth(), 0)),
store.get_node(set.root(), NodeIndex::new(set.depth() - 1, 0)),
"node 0 must be the same for both SparseMerkleTree and MerkleStore"
);
assert_eq!(
set.get_node(NodeIndex::new(set.depth(), 1)),
store.get_node(set.root(), NodeIndex::new(set.depth() - 1, 1)),
"node 1 must be the same for both SparseMerkleTree and MerkleStore"
);
assert_eq!(
set.get_node(NodeIndex::new(set.depth(), 2)),
store.get_node(set.root(), NodeIndex::new(set.depth() - 1, 2)),
"node 2 must be the same for both SparseMerkleTree and MerkleStore"
);
assert_eq!(
set.get_node(NodeIndex::new(set.depth(), 3)),
store.get_node(set.root(), NodeIndex::new(set.depth() - 1, 3)),
"node 3 must be the same for both SparseMerkleTree and MerkleStore"
);
// STORE MERKLE PATH MATCHS ==============================================================
// assert the merkle path returned by the store is the same as the one in the set
let result = store
.get_path(set.root(), NodeIndex::new(set.depth() - 1, 0))
.unwrap();
assert_eq!(
LEAVES4[0], result.0,
"Value for merkle path at index 0 must match leaf value"
);
assert_eq!(
set.get_path(NodeIndex::new(set.depth(), 0)),
Ok(result.1),
"merkle path for index 0 must be the same for the MerkleTree and MerkleStore"
);
let result = store
.get_path(set.root(), NodeIndex::new(set.depth() - 1, 1))
.unwrap();
assert_eq!(
LEAVES4[1], result.0,
"Value for merkle path at index 0 must match leaf value"
);
assert_eq!(
set.get_path(NodeIndex::new(set.depth(), 1)),
Ok(result.1),
"merkle path for index 1 must be the same for the MerkleTree and MerkleStore"
);
let result = store
.get_path(set.root(), NodeIndex::new(set.depth() - 1, 2))
.unwrap();
assert_eq!(
LEAVES4[2], result.0,
"Value for merkle path at index 0 must match leaf value"
);
assert_eq!(
set.get_path(NodeIndex::new(set.depth(), 2)),
Ok(result.1),
"merkle path for index 0 must be the same for the MerkleTree and MerkleStore"
);
let result = store
.get_path(set.root(), NodeIndex::new(set.depth() - 1, 3))
.unwrap();
assert_eq!(
LEAVES4[3], result.0,
"Value for merkle path at index 0 must match leaf value"
);
assert_eq!(
set.get_path(NodeIndex::new(set.depth(), 3)),
Ok(result.1),
"merkle path for index 0 must be the same for the MerkleTree and MerkleStore"
);
Ok(())
}
#[test]
fn wont_open_to_different_depth_root() {
let empty = EmptySubtreeRoots::empty_hashes(64);
let a = [Felt::new(1); 4];
let b = [Felt::new(2); 4];
// Compute the root for a different depth. We cherry-pick this specific depth to prevent a
// regression to a bug in the past that allowed the user to fetch a node at a depth lower than
// the inserted path of a Merkle tree.
let mut root = Rpo256::merge(&[a.into(), b.into()]);
for depth in (1..=63).rev() {
root = Rpo256::merge(&[root, empty[depth]]);
}
let root = Word::from(root);
// For this example, the depth of the Merkle tree is 1, as we have only two leaves. Here we
// attempt to fetch a node on the maximum depth, and it should fail because the root shouldn't
// exist for the set.
let store = MerkleStore::default().with_merkle_tree([a, b]).unwrap();
let index = NodeIndex::root();
let err = store.get_node(root, index).err().unwrap();
assert_eq!(err, MerkleError::RootNotInStore(root));
}
#[test]
fn store_path_opens_from_leaf() {
let a = [Felt::new(1); 4];
let b = [Felt::new(2); 4];
let c = [Felt::new(3); 4];
let d = [Felt::new(4); 4];
let e = [Felt::new(5); 4];
let f = [Felt::new(6); 4];
let g = [Felt::new(7); 4];
let h = [Felt::new(8); 4];
let i = Rpo256::merge(&[a.into(), b.into()]);
let j = Rpo256::merge(&[c.into(), d.into()]);
let k = Rpo256::merge(&[e.into(), f.into()]);
let l = Rpo256::merge(&[g.into(), h.into()]);
let m = Rpo256::merge(&[i.into(), j.into()]);
let n = Rpo256::merge(&[k.into(), l.into()]);
let root = Rpo256::merge(&[m.into(), n.into()]);
let store = MerkleStore::default()
.with_merkle_tree([a, b, c, d, e, f, g, h])
.unwrap();
let path = store.get_path(root.into(), NodeIndex::new(3, 1)).unwrap();
let expected = MerklePath::new([a.into(), j.into(), n.into()].to_vec());
assert_eq!(path.1, expected);
}
#[test]
fn test_set_node() -> Result<(), MerkleError> {
let mtree = MerkleTree::new(LEAVES4.to_vec())?;
let mut store = MerkleStore::default().with_merkle_tree(LEAVES4)?;
let value = int_to_node(42);
let index = NodeIndex::new(mtree.depth(), 0);
let new_root = store.set_node(mtree.root(), index, value)?;
assert_eq!(
store.get_node(new_root, index),
Ok(value),
"Value must have changed"
);
Ok(())
}