Merge #526: Serde for DescriptorPublicKey

3502477 Serde for DescriptorPublicKey (Scott Robinson)

Pull request description:

  Save me from ever writing the following code again:

  ```rust
  pub mod serde_descriptor_key {
      use std::str::FromStr;

      use miniscript::DescriptorPublicKey;
      use serde::{Deserialize, Deserializer, Serializer};

      pub fn serialize<S>(dpk: &DescriptorPublicKey, serializer: S) -> Result<S::Ok, S::Error>
      where
          S: Serializer,
      {
          serializer.serialize_str(&dpk.to_string())
      }

      pub fn deserialize<'de, D>(deserializer: D) -> Result<DescriptorPublicKey, D::Error>
      where
          D: Deserializer<'de>,
      {
          let s = String::deserialize(deserializer)?;
          DescriptorPublicKey::from_str(&s).map_err(serde::de::Error::custom)
      }
  }
  ```

ACKs for top commit:
  apoelstra:
    ACK 3502477
  sanket1729:
    ACK 3502477

Tree-SHA512: 0d4c13f9944d1419baf76b1443daf8f1d200b1901c7510bb44cca16967bf71a9d44825e758984ae45bc8f7a47534455b99cc355f9e421c08c3b9d32dcc677be4

Author: apoelstra

Cargo.toml

@@ -33,6 +33,7 @@ actual-serde = { package = "serde", version = "1.0", optional = true }
 bitcoind = { version = "0.27.0", features=["23_0"] }
 actual-rand = { package = "rand", version = "0.8.4"}
 secp256k1 = {version = "0.24.0", features = ["rand-std"]}
+serde_test = "1.0.147"
 
 [[example]]
 name = "htlc"

src/descriptor/key.rs

@@ -12,6 +12,8 @@ use bitcoin::util::bip32;
 use bitcoin::{self, XOnlyPublicKey, XpubIdentifier};
 
 use crate::prelude::*;
+#[cfg(feature = "serde")]
+use crate::serde::{Deserialize, Deserializer, Serialize, Serializer};
 use crate::{hash256, MiniscriptKey, ToPublicKey};
 
 /// The descriptor pubkey, either a single pubkey or an xpub.
@@ -1150,12 +1152,35 @@ impl Borrow<DescriptorPublicKey> for DefiniteDescriptorKey {
     }
 }
 
+#[cfg(feature = "serde")]
+impl<'de> Deserialize<'de> for DescriptorPublicKey {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let s = String::deserialize(deserializer)?;
+        DescriptorPublicKey::from_str(&s).map_err(crate::serde::de::Error::custom)
+    }
+}
+
+#[cfg(feature = "serde")]
+impl Serialize for DescriptorPublicKey {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(&self.to_string())
+    }
+}
+
 #[cfg(test)]
 mod test {
     use core::str::FromStr;
 
     use bitcoin::secp256k1;
     use bitcoin::util::bip32;
+    #[cfg(feature = "serde")]
+    use serde_test::{assert_tokens, Token};
 
     use super::{
         DescriptorKeyParseError, DescriptorMultiXKey, DescriptorPublicKey, DescriptorSecretKey,
@@ -1534,4 +1559,12 @@ mod test {
         DescriptorPublicKey::from_str("tpubDBrgjcxBxnXyL575sHdkpKohWu5qHKoQ7TJXKNrYznh5fVEGBv89hA8ENW7A8MFVpFUSvgLqc4Nj1WZcpePX6rrxviVtPowvMuGF5rdT2Vi/2/4/<;1>").unwrap_err();
         DescriptorPublicKey::from_str("tpubDBrgjcxBxnXyL575sHdkpKohWu5qHKoQ7TJXKNrYznh5fVEGBv89hA8ENW7A8MFVpFUSvgLqc4Nj1WZcpePX6rrxviVtPowvMuGF5rdT2Vi/2/4/<0;1;>").unwrap_err();
     }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_descriptor_public_key_serde() {
+        let desc = "[abcdef00/0'/1']tpubDBrgjcxBxnXyL575sHdkpKohWu5qHKoQ7TJXKNrYznh5fVEGBv89hA8ENW7A8MFVpFUSvgLqc4Nj1WZcpePX6rrxviVtPowvMuGF5rdT2Vi/2";
+        let public_key = DescriptorPublicKey::from_str(desc).unwrap();
+        assert_tokens(&public_key, &[Token::String(desc)]);
+    }
 }