Merge rust-bitcoin/rust-bitcoin#1523: Fix LeafVersion serde

a400757676 Add failing tests from serde-json (sanket1729)
b3246bf73f Fix LeafVersion serde (sanket1729)

Pull request description:

  The default implementation maps to visit_u64. The current implementation
  does not roundtrip with many deserializers, including serde_json. See
  the failing test in the second commit

ACKs for top commit:
  Kixunil:
    tACK a400757676
  tcharding:
    ACK a400757676

Tree-SHA512: a6307b799b0bb4af398addc9ddbff0d811b632d1cc6ab4bdd77aaf3f151e48dd1cd10e3f90a71ef8fc3feb1cd988f7a719f92ec745b5fdf2ae0f0ad97ab2fa10

bitcoin/src/taproot.rs

@@ -944,10 +944,16 @@ impl<'de> serde::Deserialize<'de> for LeafVersion {
                 formatter.write_str("a valid consensus-encoded taproot leaf version")
             }
 
-            fn visit_u8<E>(self, value: u8) -> Result<Self::Value, E>
+            fn visit_u64<E>(self, value: u64) -> Result<Self::Value, E>
             where
                 E: serde::de::Error,
             {
+                let value = u8::try_from(value).map_err(|_| {
+                    E::invalid_value(
+                        serde::de::Unexpected::Unsigned(value),
+                        &"consensus-encoded leaf version as u8",
+                    )
+                })?;
                 LeafVersion::from_consensus(value).map_err(|_| {
                     E::invalid_value(
                         ::serde::de::Unexpected::Unsigned(value as u64),
@@ -1098,6 +1104,9 @@ mod test {
     use crate::{Address, Network};
     extern crate serde_json;
 
+    #[cfg(feature = "serde")]
+    use serde_test::{assert_tokens, Token};
+
     fn tag_engine(tag_name: &str) -> sha256::HashEngine {
         let mut engine = sha256::Hash::engine();
         let tag_hash = sha256::Hash::hash(tag_name.as_bytes());
@@ -1351,6 +1360,18 @@ mod test {
         }
     }
 
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_leaf_version_serde() {
+        let leaf_version = LeafVersion::TapScript;
+        // use serde_test to test serialization and deserialization
+        assert_tokens(&leaf_version, &[Token::U8(192)]);
+
+        let json = serde_json::to_string(&leaf_version).unwrap();
+        let leaf_version2 = serde_json::from_str(&json).unwrap();
+        assert_eq!(leaf_version, leaf_version2);
+    }
+
     #[test]
     fn bip_341_tests() {
         fn process_script_trees(