feature: add conditional support for serde

src/merkle/tiered_smt/mod.rs

@@ -43,6 +43,7 @@ mod tests;
 /// - Leaf node at depths 16, 32, or 64: hash(key, value, domain=depth).
 /// - Leaf node at depth 64: hash([key_0, value_0, ..., key_n, value_n], domain=64).
 #[derive(Debug, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct TieredSmt {
     root: RpoDigest,
     nodes: NodeStore,

src/merkle/tiered_smt/nodes.rs

@@ -24,6 +24,7 @@ const MAX_DEPTH: u8 = super::TieredSmt::MAX_DEPTH;
 /// represent leaf nodes in a Tiered Sparse Merkle tree. In the current implementation, [BTreeSet]s
 /// are used to determine the position of the leaves in the tree.
 #[derive(Debug, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct NodeStore {
     nodes: BTreeMap<NodeIndex, RpoDigest>,
     upper_leaves: BTreeSet<NodeIndex>,

src/merkle/tiered_smt/values.rs

@@ -26,6 +26,7 @@ const MAX_DEPTH: u8 = super::TieredSmt::MAX_DEPTH;
 /// The store supports lookup by the full key (i.e. [RpoDigest]) as well as by the 64-bit key
 /// prefix.
 #[derive(Debug, Default, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct ValueStore {
     values: BTreeMap<u64, StoreEntry>,
 }
@@ -173,6 +174,7 @@ impl ValueStore {
 /// An entry can contain either a single key-value pair or a vector of key-value pairs sorted by
 /// key.
 #[derive(Debug, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub enum StoreEntry {
     Single((RpoDigest, Word)),
     List(Vec<(RpoDigest, Word)>),