make fx_hashmap_serde public for downstream reuse

salt/src/lib.rs

@@ -7,7 +7,7 @@ extern crate alloc as std;
 pub mod constant;
 pub mod empty_salt;
 pub mod proof;
-pub use proof::{ProofError, SaltProof, SaltWitness, Witness};
+pub use proof::{fx_hashmap_serde, ProofError, SaltProof, SaltWitness, Witness};
 pub mod state;
 pub use state::{
     hasher, state::EphemeralSaltState, state::PlainStateProvider, updates::StateUpdates,

salt/src/proof/mod.rs

@@ -76,7 +76,7 @@ pub mod witness;
 #[cfg(test)]
 mod test_utils;
 
-pub use prover::{SaltProof, SerdeCommitment, SerdeMultiPointProof};
+pub use prover::{fx_hashmap_serde, SaltProof, SerdeCommitment, SerdeMultiPointProof};
 pub use salt_witness::SaltWitness;
 pub use witness::Witness;
 

salt/src/proof/prover.rs

@@ -118,11 +118,12 @@ pub struct SaltProof {
     pub levels: FxHashMap<BucketId, u8>,
 }
 
-// Hand-written (de)serialization for `levels` so the salt crate doesn't need
-// to enable `hashbrown/serde` (which transitively pulls in serde_core 1.0.221+
-// and breaks downstream alloy-tx-macros 1.0.23). Entries are emitted in
-// ascending key order to keep proof bytes deterministic across provers.
-mod fx_hashmap_serde {
+/// Hand-written (de)serialization for `levels` so the salt crate doesn't need
+/// to enable `hashbrown/serde` (which transitively pulls in serde_core 1.0.221+
+/// and breaks downstream alloy-tx-macros 1.0.23). Entries are emitted in
+/// ascending key order to keep proof bytes deterministic across provers.
+/// Also reused downstream (e.g. `stateless-core::LightWitness`) via `#[serde(with = "salt::fx_hashmap_serde")]`.
+pub mod fx_hashmap_serde {
     use super::*;
 
     pub fn serialize<S: Serializer>(