Remove N_BYTES generic parameter form Tree trait (#282)

backend/examples/summa_solvency_flow.rs

@@ -16,6 +16,7 @@ use summa_backend::{
 use summa_solvency::merkle_sum_tree::MerkleSumTree;
 
 const N_CURRENCIES: usize = 2;
+const N_BYTES: usize = 8;
 const USER_INDEX: usize = 0;
 
 #[tokio::main]
@@ -59,11 +60,13 @@ async fn main() -> Result<(), Box<dyn Error>> {
     // Initialize the `Round` instance to submit the liability commitment.
     let params_path = "ptau/hermez-raw-11";
     let entry_csv = "../csv/entry_16.csv";
-    let mst = MerkleSumTree::from_csv(entry_csv).unwrap();
+    let mst = MerkleSumTree::<N_CURRENCIES, N_BYTES>::from_csv(entry_csv).unwrap();
 
     // Using the `round` instance, the commitment is dispatched to the Summa contract with the `dispatch_commitment` method.
     let timestamp = 1u64;
-    let mut round = Round::<4, 2, 8>::new(&signer, Box::new(mst), params_path, timestamp).unwrap();
+    let mut round =
+        Round::<4, N_CURRENCIES, N_BYTES>::new(&signer, Box::new(mst), params_path, timestamp)
+            .unwrap();
 
     // Sends the commitment, which should ideally complete without errors.
     round.dispatch_commitment().await?;

backend/src/apis/round.rs

@@ -39,7 +39,7 @@ impl MstInclusionProof {
 }
 
 pub struct Snapshot<const LEVELS: usize, const N_CURRENCIES: usize, const N_BYTES: usize> {
-    pub mst: Box<dyn Tree<N_CURRENCIES, N_BYTES>>,
+    pub mst: Box<dyn Tree<N_CURRENCIES>>,
     trusted_setup: SetupArtifacts,
 }
 
@@ -57,7 +57,7 @@ where
 {
     pub fn new<'a>(
         signer: &'a SummaSigner,
-        mst: Box<dyn Tree<N_CURRENCIES, N_BYTES>>,
+        mst: Box<dyn Tree<N_CURRENCIES>>,
         params_path: &str,
         timestamp: u64,
     ) -> Result<Round<'a, LEVELS, N_CURRENCIES, N_BYTES>, Box<dyn Error>>
@@ -130,7 +130,7 @@ where
     [usize; N_CURRENCIES + 2]: Sized,
 {
     pub fn new(
-        mst: Box<dyn Tree<N_CURRENCIES, N_BYTES>>,
+        mst: Box<dyn Tree<N_CURRENCIES>>,
         params_path: &str,
     ) -> Result<Snapshot<LEVELS, N_CURRENCIES, N_BYTES>, Box<dyn std::error::Error>> {
         let mst_inclusion_circuit =

backend/src/tests.rs

@@ -158,7 +158,7 @@ mod test {
 
         let params_path = "ptau/hermez-raw-11";
         let entry_csv = "../csv/entry_16.csv";
-        let mst = MerkleSumTree::from_csv(entry_csv).unwrap();
+        let mst = MerkleSumTree::<2, 8>::from_csv(entry_csv).unwrap();
 
         let mut round_one =
             Round::<4, 2, 8>::new(&signer, Box::new(mst.clone()), params_path, 1).unwrap();
@@ -238,7 +238,7 @@ mod test {
         let params_path = "ptau/hermez-raw-11";
         let entry_csv = "../csv/entry_16.csv";
 
-        let mst = MerkleSumTree::from_csv(entry_csv).unwrap();
+        let mst = MerkleSumTree::<2, 8>::from_csv(entry_csv).unwrap();
         let mut round = Round::<4, 2, 8>::new(&signer, Box::new(mst), params_path, 1).unwrap();
 
         let mut liability_commitment_logs = summa_contract

zk_prover/src/circuits/merkle_sum_tree.rs

@@ -83,7 +83,7 @@ where
     }
 
     /// Initializes the circuit with the merkle proof and the entry of the user of which the inclusion is to be verified.
-    pub fn init(merkle_proof: MerkleProof<N_CURRENCIES, N_BYTES>) -> Self
+    pub fn init(merkle_proof: MerkleProof<N_CURRENCIES>) -> Self
     where
         [usize; N_CURRENCIES + 1]: Sized,
         [usize; N_CURRENCIES + 2]: Sized,

zk_prover/src/merkle_sum_tree/mod.rs

@@ -14,7 +14,7 @@ use halo2_proofs::halo2curves::bn256::Fr as Fp;
 /// * `sibling_leaf_node_hash_preimage`: The hash preimage of the sibling leaf node. The hash preimage is equal to `[sibling_username, sibling.balance[0], sibling.balance[1], ... sibling.balance[N_CURRENCIES - 1]]`
 /// * `sibling_middle_node_hash_preimages`: The hash preimages of the sibling middle nodes. The hash preimage is equal to `[sibling_left_child.balance[0] + sibling_right_child.balance[0], sibling_left_child.balance[1] + sibling_right_child.balance[1], ..., sibling_left_child.balance[N_CURRENCIES - 1] + sibling_right_child.balance[N_CURRENCIES - 1], sibling_left_child.hash, sibling_right_child.hash]`
 #[derive(Clone, Debug)]
-pub struct MerkleProof<const N_CURRENCIES: usize, const N_BYTES: usize>
+pub struct MerkleProof<const N_CURRENCIES: usize>
 where
     [usize; N_CURRENCIES + 1]: Sized,
     [usize; N_CURRENCIES + 2]: Sized,

zk_prover/src/merkle_sum_tree/mst.rs

@@ -27,7 +27,7 @@ pub struct MerkleSumTree<const N_CURRENCIES: usize, const N_BYTES: usize> {
     is_sorted: bool,
 }
 
-impl<const N_CURRENCIES: usize, const N_BYTES: usize> Tree<N_CURRENCIES, N_BYTES>
+impl<const N_CURRENCIES: usize, const N_BYTES: usize> Tree<N_CURRENCIES>
     for MerkleSumTree<N_CURRENCIES, N_BYTES>
 {
     fn root(&self) -> &Node<N_CURRENCIES> {

zk_prover/src/merkle_sum_tree/tree.rs

@@ -4,7 +4,7 @@ use crate::merkle_sum_tree::{Entry, MerkleProof, Node};
 use halo2_proofs::halo2curves::bn256::Fr as Fp;
 
 /// A trait representing the basic operations for a Merkle-Sum-like Tree.
-pub trait Tree<const N_CURRENCIES: usize, const N_BYTES: usize> {
+pub trait Tree<const N_CURRENCIES: usize> {
     /// Returns a reference to the root node.
     fn root(&self) -> &Node<N_CURRENCIES>;
 
@@ -85,7 +85,7 @@ pub trait Tree<const N_CURRENCIES: usize, const N_BYTES: usize> {
     fn generate_proof(
         &self,
         index: usize,
-    ) -> Result<MerkleProof<N_CURRENCIES, N_BYTES>, Box<dyn std::error::Error>>
+    ) -> Result<MerkleProof<N_CURRENCIES>, Box<dyn std::error::Error>>
     where
         [usize; N_CURRENCIES + 1]: Sized,
         [usize; N_CURRENCIES + 2]: Sized,
@@ -134,7 +134,7 @@ pub trait Tree<const N_CURRENCIES: usize, const N_BYTES: usize> {
     }
 
     /// Verifies a MerkleProof.
-    fn verify_proof(&self, proof: &MerkleProof<N_CURRENCIES, N_BYTES>) -> bool
+    fn verify_proof(&self, proof: &MerkleProof<N_CURRENCIES>) -> bool
     where
         [usize; N_CURRENCIES + 1]: Sized,
         [usize; N_CURRENCIES + 2]: Sized,