Remove serde implementation for GroupElement

Author: stanislav-tkach

rust/catalyst-contest/Cargo.toml

@@ -25,6 +25,7 @@ serde = { version = "1.0.228", features = ["derive"] }
 serde_json = "1.0.145"
 strum = { version = "0.27", features = ["derive"] }
 chrono = { version = "0.4.42", features = ["serde"] }
+hex = "0.4.3"
 
 [dev-dependencies]
 proptest = { version = "1.6.0", features = ["attr-macro"] }

rust/catalyst-contest/src/contest_parameters/mod.rs

@@ -6,6 +6,7 @@
 
 pub mod rule;
 
+mod serde_group_element;
 #[cfg(test)]
 mod tests;
 
@@ -45,6 +46,7 @@ pub(crate) struct ContestParametersPayload {
     /// Contest end date
     pub(crate) end: DateTime<Utc>,
     /// An election public key.
+    #[serde(with = "serde_group_element")]
     pub(crate) election_public_key: GroupElement,
 }
 

rust/catalyst-contest/src/contest_parameters/serde_group_element.rs

@@ -0,0 +1,47 @@
+//! A serialize/deserialize implementation for `GroupElement`.
+
+use catalyst_voting::crypto::group::GroupElement;
+use serde::{Deserialize, Deserializer, Serializer};
+
+pub fn serialize<S>(
+    val: &GroupElement,
+    serializer: S,
+) -> Result<S::Ok, S::Error>
+where
+    S: Serializer,
+{
+    let hex = hex::encode(val.to_bytes());
+    serializer.serialize_str(&hex)
+}
+
+pub fn deserialize<'de, D>(deserializer: D) -> Result<GroupElement, D::Error>
+where D: Deserializer<'de> {
+    let hex = String::deserialize(deserializer)?;
+    let bytes = hex::decode(hex).map_err(serde::de::Error::custom)?;
+    let array = <[u8; GroupElement::BYTES_SIZE]>::try_from(bytes.as_slice())
+        .map_err(serde::de::Error::custom)?;
+    GroupElement::from_bytes(&array).map_err(serde::de::Error::custom)
+}
+
+#[cfg(test)]
+mod tests {
+    use serde::Serialize;
+
+    use super::*;
+
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Wrapper {
+        #[serde(with = "super")]
+        value: GroupElement,
+    }
+
+    #[test]
+    fn group_element_json_roundtrip() {
+        let original = Wrapper {
+            value: GroupElement::zero(),
+        };
+        let json = serde_json::to_string(&original).unwrap();
+        let decoded = serde_json::from_str(&json).unwrap();
+        assert_eq!(original, decoded);
+    }
+}

rust/catalyst-voting/Cargo.toml

@@ -25,8 +25,6 @@ ed25519-dalek = { version = "2.1.1", features = ["rand_core"] }
 blake2b_simd = "1.0.2"
 rayon = "1.10.0"
 minicbor = { version = "0.25.1", features = ["alloc", "derive", "half"] }
-serde = { version = "1.0.228", features = ["derive"] }
-hex = "0.4.3"
 
 cbork-utils = { version = "0.0.2", git = "https://github.com/input-output-hk/catalyst-libs.git", tag = "cbork-utils-v0.0.2" }
 
@@ -36,4 +34,3 @@ proptest = { version = "1.6.0", features = ["attr-macro"] }
 # Potentially it could be replaced with using `proptest::property_test` attribute macro,
 # after this PR will be merged https://github.com/proptest-rs/proptest/pull/523
 test-strategy = "0.4.0"
-serde_json = "1.0.145"

rust/catalyst-voting/src/crypto/group/ristretto255/decoding.rs

@@ -91,30 +91,6 @@ impl Decode<'_, ()> for GroupElement {
     }
 }
 
-impl serde::Serialize for GroupElement {
-    fn serialize<S>(
-        &self,
-        serializer: S,
-    ) -> Result<S::Ok, S::Error>
-    where
-        S: serde::Serializer,
-    {
-        let hex = hex::encode(self.to_bytes());
-        serializer.serialize_str(&hex)
-    }
-}
-
-impl<'de> serde::Deserialize<'de> for GroupElement {
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-    where D: serde::Deserializer<'de> {
-        let hex = String::deserialize(deserializer)?;
-        let bytes = hex::decode(hex).map_err(serde::de::Error::custom)?;
-        let array = <[u8; GroupElement::BYTES_SIZE]>::try_from(bytes.as_slice())
-            .map_err(serde::de::Error::custom)?;
-        Self::from_bytes(&array).map_err(serde::de::Error::custom)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use test_strategy::proptest;
@@ -154,11 +130,4 @@ mod tests {
         let decoded = GroupElement::decode(&mut Decoder::new(&buffer), &mut ()).unwrap();
         assert_eq!(original, decoded);
     }
-
-    #[proptest]
-    fn group_element_json_roundtrip(original: GroupElement) {
-        let json = serde_json::to_string(&original).unwrap();
-        let decoded = serde_json::from_str(&json).unwrap();
-        assert_eq!(original, decoded);
-    }
 }