perf: avoid unnecessary clone when building Merkle trees

crypto/src/merkle_tree/merkle.rs

@@ -31,10 +31,10 @@ where
     B: IsMerkleTreeBackend,
 {
     pub fn build(unhashed_leaves: &[B::Data]) -> Self {
-        let mut hashed_leaves: Vec<B::Node> = B::hash_leaves(unhashed_leaves);
+        let hashed_leaves: Vec<B::Node> = B::hash_leaves(unhashed_leaves);
 
         //The leaf must be a power of 2 set
-        hashed_leaves = complete_until_power_of_two(&mut hashed_leaves);
+        let hashed_leaves = complete_until_power_of_two(hashed_leaves);
         let leaves_len = hashed_leaves.len();
 
         //The length of leaves minus one inner node in the merkle tree

crypto/src/merkle_tree/utils.rs

@@ -21,11 +21,11 @@ pub fn parent_index(node_index: usize) -> usize {
 }
 
 // The list of values is completed repeating the last value to a power of two length
-pub fn complete_until_power_of_two<T: Clone>(values: &mut Vec<T>) -> Vec<T> {
+pub fn complete_until_power_of_two<T: Clone>(mut values: Vec<T>) -> Vec<T> {
     while !is_power_of_two(values.len()) {
         values.push(values[values.len() - 1].clone());
     }
-    values.to_vec()
+    values
 }
 
 // ! NOTE !
@@ -101,8 +101,8 @@ mod tests {
     #[test]
     // expected |1|2|3|4|5|5|5|5|
     fn complete_the_length_of_a_list_of_fields_elements_to_be_a_power_of_two() {
-        let mut values: Vec<FE> = (1..6).map(FE::new).collect();
-        let hashed_leaves = complete_until_power_of_two(&mut values);
+        let values: Vec<FE> = (1..6).map(FE::new).collect();
+        let hashed_leaves = complete_until_power_of_two(values);
 
         let mut expected_leaves = (1..6).map(FE::new).collect::<Vec<FE>>();
         expected_leaves.extend([FE::new(5); 3]);
@@ -115,8 +115,8 @@ mod tests {
     #[test]
     // expected |2|2|
     fn complete_the_length_of_one_field_element_to_be_a_power_of_two() {
-        let mut values: Vec<FE> = vec![FE::new(2)];
-        let hashed_leaves = complete_until_power_of_two(&mut values);
+        let values: Vec<FE> = vec![FE::new(2)];
+        let hashed_leaves = complete_until_power_of_two(values);
 
         let mut expected_leaves = vec![FE::new(2)];
         expected_leaves.extend([FE::new(2)]);