Merge pull request #61 from BitGo/BTC-1826.add-fromStringDetectType

feat(miniscript): add descriptor type detection and custom error

Author: OttoAllmendinger

packages/wasm-miniscript/js/index.ts

@@ -20,6 +20,7 @@ declare module "./wasm/wasm_miniscript" {
 
   namespace WrapDescriptor {
     function fromString(descriptor: string, pkType: DescriptorPkType): WrapDescriptor;
+    function fromStringDetectType(descriptor: string): WrapDescriptor;
   }
 
   interface WrapMiniscript {

packages/wasm-miniscript/src/descriptor.rs

@@ -1,11 +1,11 @@
+use crate::error::WasmMiniscriptError;
 use crate::try_into_js_value::TryIntoJsValue;
-use miniscript::bitcoin::secp256k1::Secp256k1;
+use miniscript::bitcoin::secp256k1::{Context, Secp256k1, Signing};
 use miniscript::bitcoin::ScriptBuf;
 use miniscript::descriptor::KeyMap;
 use miniscript::{DefiniteDescriptorKey, Descriptor, DescriptorPublicKey};
 use std::str::FromStr;
-use wasm_bindgen::prelude::wasm_bindgen;
-use wasm_bindgen::{JsError, JsValue};
+use wasm_bindgen::prelude::*;
 
 pub(crate) enum WrapDescriptorEnum {
     Derivable(Descriptor<DescriptorPublicKey>, KeyMap),
@@ -18,7 +18,7 @@ pub struct WrapDescriptor(pub(crate) WrapDescriptorEnum);
 
 #[wasm_bindgen]
 impl WrapDescriptor {
-    pub fn node(&self) -> Result<JsValue, JsError> {
+    pub fn node(&self) -> Result<JsValue, WasmMiniscriptError> {
         Ok(match &self.0 {
             WrapDescriptorEnum::Derivable(desc, _) => desc.try_to_js_value()?,
             WrapDescriptorEnum::Definite(desc) => desc.try_to_js_value()?,
@@ -45,18 +45,20 @@ impl WrapDescriptor {
     }
 
     #[wasm_bindgen(js_name = atDerivationIndex)]
-    pub fn at_derivation_index(&self, index: u32) -> Result<WrapDescriptor, JsError> {
+    pub fn at_derivation_index(&self, index: u32) -> Result<WrapDescriptor, WasmMiniscriptError> {
         match &self.0 {
             WrapDescriptorEnum::Derivable(desc, _keys) => {
                 let d = desc.at_derivation_index(index)?;
                 Ok(WrapDescriptor(WrapDescriptorEnum::Definite(d)))
             }
-            _ => Err(JsError::new("Cannot derive from a definite descriptor")),
+            _ => Err(WasmMiniscriptError::new(
+                "Cannot derive from a definite descriptor",
+            )),
         }
     }
 
     #[wasm_bindgen(js_name = descType)]
-    pub fn desc_type(&self) -> Result<JsValue, JsError> {
+    pub fn desc_type(&self) -> Result<JsValue, WasmMiniscriptError> {
         (match &self.0 {
             WrapDescriptorEnum::Derivable(desc, _) => desc.desc_type(),
             WrapDescriptorEnum::Definite(desc) => desc.desc_type(),
@@ -66,34 +68,38 @@ impl WrapDescriptor {
     }
 
     #[wasm_bindgen(js_name = scriptPubkey)]
-    pub fn script_pubkey(&self) -> Result<Vec<u8>, JsError> {
+    pub fn script_pubkey(&self) -> Result<Vec<u8>, WasmMiniscriptError> {
         match &self.0 {
             WrapDescriptorEnum::Definite(desc) => Ok(desc.script_pubkey().to_bytes()),
-            _ => Err(JsError::new("Cannot derive from a non-definite descriptor")),
+            _ => Err(WasmMiniscriptError::new(
+                "Cannot encode a derivable descriptor",
+            )),
         }
     }
 
-    fn explicit_script(&self) -> Result<ScriptBuf, JsError> {
+    fn explicit_script(&self) -> Result<ScriptBuf, WasmMiniscriptError> {
         match &self.0 {
             WrapDescriptorEnum::Definite(desc) => Ok(desc.explicit_script()?),
-            WrapDescriptorEnum::Derivable(_, _) => {
-                Err(JsError::new("Cannot encode a derivable descriptor"))
-            }
-            WrapDescriptorEnum::String(_) => Err(JsError::new("Cannot encode a string descriptor")),
+            WrapDescriptorEnum::Derivable(_, _) => Err(WasmMiniscriptError::new(
+                "Cannot encode a derivable descriptor",
+            )),
+            WrapDescriptorEnum::String(_) => Err(WasmMiniscriptError::new(
+                "Cannot encode a string descriptor",
+            )),
         }
     }
 
-    pub fn encode(&self) -> Result<Vec<u8>, JsError> {
+    pub fn encode(&self) -> Result<Vec<u8>, WasmMiniscriptError> {
         Ok(self.explicit_script()?.to_bytes())
     }
 
     #[wasm_bindgen(js_name = toAsmString)]
-    pub fn to_asm_string(&self) -> Result<String, JsError> {
+    pub fn to_asm_string(&self) -> Result<String, WasmMiniscriptError> {
         Ok(self.explicit_script()?.to_asm_string())
     }
 
     #[wasm_bindgen(js_name = maxWeightToSatisfy)]
-    pub fn max_weight_to_satisfy(&self) -> Result<u32, JsError> {
+    pub fn max_weight_to_satisfy(&self) -> Result<u32, WasmMiniscriptError> {
         let weight = (match &self.0 {
             WrapDescriptorEnum::Derivable(desc, _) => desc.max_weight_to_satisfy(),
             WrapDescriptorEnum::Definite(desc) => desc.max_weight_to_satisfy(),
@@ -102,26 +108,124 @@ impl WrapDescriptor {
         weight
             .to_wu()
             .try_into()
-            .map_err(|_| JsError::new("Weight exceeds u32"))
+            .map_err(|_| WasmMiniscriptError::new("Weight exceeds u32"))
+    }
+
+    fn from_string_derivable<C: Signing>(
+        secp: &Secp256k1<C>,
+        descriptor: &str,
+    ) -> Result<WrapDescriptor, WasmMiniscriptError> {
+        let (desc, keys) = Descriptor::parse_descriptor(&secp, descriptor)?;
+        Ok(WrapDescriptor(WrapDescriptorEnum::Derivable(desc, keys)))
+    }
+
+    fn from_string_definite(descriptor: &str) -> Result<WrapDescriptor, WasmMiniscriptError> {
+        let desc = Descriptor::<DefiniteDescriptorKey>::from_str(descriptor)?;
+        Ok(WrapDescriptor(WrapDescriptorEnum::Definite(desc)))
     }
 
+    /// Parse a descriptor string with an explicit public key type.
+    ///
+    /// Note that this function permits parsing a non-derivable descriptor with a derivable key type.
+    /// Use `from_string_detect_type` to automatically detect the key type.
+    ///
+    /// # Arguments
+    /// * `descriptor` - A string containing the descriptor to parse
+    /// * `pk_type` - The type of public key to expect:
+    ///   - "derivable": For descriptors containing derivation paths (eg. xpubs)
+    ///   - "definite": For descriptors with fully specified keys
+    ///   - "string": For descriptors with string placeholders
+    ///
+    /// # Returns
+    /// * `Result<WrapDescriptor, WasmMiniscriptError>` - The parsed descriptor or an error
+    ///
+    /// # Example
+    /// ```
+    /// let desc = WrapDescriptor::from_string(
+    ///   "pk(xpub661MyMwAqRbcFtXgS5sYJABqqG9YLmC4Q1Rdap9gSE8NqtwybGhePY2gZ29ESFjqJoCu1Rupje8YtGqsefD265TMg7usUDFdp6W1EGMcet8/*)",
+    ///   "derivable"
+    /// );
+    /// ```
     #[wasm_bindgen(js_name = fromString, skip_typescript)]
-    pub fn from_string(descriptor: &str, pk_type: &str) -> Result<WrapDescriptor, JsError> {
+    pub fn from_string(
+        descriptor: &str,
+        pk_type: &str,
+    ) -> Result<WrapDescriptor, WasmMiniscriptError> {
         match pk_type {
-            "derivable" => {
-                let secp = Secp256k1::new();
-                let (desc, keys) = Descriptor::parse_descriptor(&secp, descriptor)?;
-                Ok(WrapDescriptor(WrapDescriptorEnum::Derivable(desc, keys)))
-            }
-            "definite" => {
-                let desc = Descriptor::<DefiniteDescriptorKey>::from_str(descriptor)?;
-                Ok(WrapDescriptor(WrapDescriptorEnum::Definite(desc)))
-            }
+            "derivable" => WrapDescriptor::from_string_derivable(&Secp256k1::new(), descriptor),
+            "definite" => WrapDescriptor::from_string_definite(descriptor),
             "string" => {
                 let desc = Descriptor::<String>::from_str(descriptor)?;
                 Ok(WrapDescriptor(WrapDescriptorEnum::String(desc)))
             }
-            _ => Err(JsError::new("Invalid descriptor type")),
+            _ => Err(WasmMiniscriptError::new("Invalid descriptor type")),
+        }
+    }
+
+    /// Parse a descriptor string, automatically detecting the appropriate public key type.
+    /// This will check if the descriptor contains wildcards to determine if it should be
+    /// parsed as derivable or definite.
+    ///
+    /// # Arguments
+    /// * `descriptor` - A string containing the descriptor to parse
+    ///
+    /// # Returns
+    /// * `Result<WrapDescriptor, WasmMiniscriptError>` - The parsed descriptor or an error
+    ///
+    /// # Example
+    /// ```
+    /// // Will be parsed as definite since it has no wildcards
+    /// let desc = WrapDescriptor::from_string_detect_type(
+    ///   "pk(02c6047f9441ed7d6d3045406e95c07cd85c778e4b8cef3ca7abac09b95c709ee5)"
+    /// );
+    ///
+    /// // Will be parsed as derivable since it contains a wildcard (*)
+    /// let desc = WrapDescriptor::from_string_detect_type(
+    ///   "pk(xpub.../0/*)"
+    /// );
+    /// ```
+    #[wasm_bindgen(js_name = fromStringDetectType, skip_typescript)]
+    pub fn from_string_detect_type(
+        descriptor: &str,
+    ) -> Result<WrapDescriptor, WasmMiniscriptError> {
+        let secp = Secp256k1::new();
+        let (descriptor, _key_map) = Descriptor::parse_descriptor(&secp, descriptor)
+            .map_err(|_| WasmMiniscriptError::new("Invalid descriptor"))?;
+        if descriptor.has_wildcard() {
+            WrapDescriptor::from_string_derivable(&secp, &descriptor.to_string())
+        } else {
+            WrapDescriptor::from_string_definite(&descriptor.to_string())
         }
     }
 }
+
+impl FromStr for WrapDescriptor {
+    type Err = WasmMiniscriptError;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        WrapDescriptor::from_string_detect_type(s)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::WrapDescriptor;
+
+    #[test]
+    fn test_detect_type() {
+        let desc = WrapDescriptor::from_string_detect_type(
+            "pk(L4rK1yDtCWekvXuE6oXD9jCYfFNV2cWRpVuPLBcCU2z8TrisoyY1)",
+        )
+        .unwrap();
+
+        assert_eq!(desc.has_wildcard(), false);
+        assert_eq!(
+            match desc {
+                WrapDescriptor {
+                    0: crate::descriptor::WrapDescriptorEnum::Definite(_),
+                } => true,
+                _ => false,
+            },
+            true
+        );
+    }
+}

packages/wasm-miniscript/src/error.rs

@@ -0,0 +1,45 @@
+use core::fmt;
+
+#[derive(Debug, Clone)]
+pub enum WasmMiniscriptError {
+    StringError(String),
+}
+
+impl std::error::Error for WasmMiniscriptError {}
+impl fmt::Display for WasmMiniscriptError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            WasmMiniscriptError::StringError(s) => write!(f, "{}", s),
+        }
+    }
+}
+
+impl From<&str> for WasmMiniscriptError {
+    fn from(s: &str) -> Self {
+        WasmMiniscriptError::StringError(s.to_string())
+    }
+}
+
+impl From<String> for WasmMiniscriptError {
+    fn from(s: String) -> Self {
+        WasmMiniscriptError::StringError(s)
+    }
+}
+
+impl From<miniscript::Error> for WasmMiniscriptError {
+    fn from(err: miniscript::Error) -> Self {
+        WasmMiniscriptError::StringError(err.to_string())
+    }
+}
+
+impl From<miniscript::descriptor::ConversionError> for WasmMiniscriptError {
+    fn from(err: miniscript::descriptor::ConversionError) -> Self {
+        WasmMiniscriptError::StringError(err.to_string())
+    }
+}
+
+impl WasmMiniscriptError {
+    pub fn new(s: &str) -> WasmMiniscriptError {
+        WasmMiniscriptError::StringError(s.to_string())
+    }
+}

packages/wasm-miniscript/src/lib.rs

@@ -1,4 +1,5 @@
 mod descriptor;
+mod error;
 mod miniscript;
 mod psbt;
 mod try_into_js_value;

packages/wasm-miniscript/src/miniscript.rs

@@ -1,10 +1,10 @@
+use crate::error::WasmMiniscriptError;
+use crate::try_into_js_value::TryIntoJsValue;
 use miniscript::bitcoin::{PublicKey, XOnlyPublicKey};
 use miniscript::{bitcoin, Legacy, Miniscript, Segwitv0, Tap};
 use std::str::FromStr;
 use wasm_bindgen::prelude::wasm_bindgen;
-use wasm_bindgen::{JsError, JsValue};
-
-use crate::try_into_js_value::TryIntoJsValue;
+use wasm_bindgen::JsValue;
 
 // Define the macro to simplify operations on WrapMiniscriptEnum variants
 // apply a func to the miniscript variant
@@ -30,7 +30,7 @@ pub struct WrapMiniscript(WrapMiniscriptEnum);
 #[wasm_bindgen]
 impl WrapMiniscript {
     #[wasm_bindgen(js_name = node)]
-    pub fn node(&self) -> Result<JsValue, JsError> {
+    pub fn node(&self) -> Result<JsValue, WasmMiniscriptError> {
         unwrap_apply!(&self.0, |ms| ms.try_to_js_value())
     }
 
@@ -45,43 +45,52 @@ impl WrapMiniscript {
     }
 
     #[wasm_bindgen(js_name = toAsmString)]
-    pub fn to_asm_string(&self) -> Result<String, JsError> {
+    pub fn to_asm_string(&self) -> Result<String, WasmMiniscriptError> {
         unwrap_apply!(&self.0, |ms| Ok(ms.encode().to_asm_string()))
     }
 
     #[wasm_bindgen(js_name = fromString, skip_typescript)]
-    pub fn from_string(script: &str, context_type: &str) -> Result<WrapMiniscript, JsError> {
+    pub fn from_string(
+        script: &str,
+        context_type: &str,
+    ) -> Result<WrapMiniscript, WasmMiniscriptError> {
         match context_type {
             "tap" => Ok(WrapMiniscript::from(
-                Miniscript::<XOnlyPublicKey, Tap>::from_str(script).map_err(JsError::from)?,
+                Miniscript::<XOnlyPublicKey, Tap>::from_str(script)
+                    .map_err(WasmMiniscriptError::from)?,
             )),
             "segwitv0" => Ok(WrapMiniscript::from(
-                Miniscript::<PublicKey, Segwitv0>::from_str(script).map_err(JsError::from)?,
+                Miniscript::<PublicKey, Segwitv0>::from_str(script)
+                    .map_err(WasmMiniscriptError::from)?,
             )),
             "legacy" => Ok(WrapMiniscript::from(
-                Miniscript::<PublicKey, Legacy>::from_str(script).map_err(JsError::from)?,
+                Miniscript::<PublicKey, Legacy>::from_str(script)
+                    .map_err(WasmMiniscriptError::from)?,
             )),
-            _ => Err(JsError::new("Invalid context type")),
+            _ => Err(WasmMiniscriptError::new("Invalid context type")),
         }
     }
 
     #[wasm_bindgen(js_name = fromBitcoinScript, skip_typescript)]
     pub fn from_bitcoin_script(
         script: &[u8],
         context_type: &str,
-    ) -> Result<WrapMiniscript, JsError> {
+    ) -> Result<WrapMiniscript, WasmMiniscriptError> {
         let script = bitcoin::Script::from_bytes(script);
         match context_type {
             "tap" => Ok(WrapMiniscript::from(
-                Miniscript::<XOnlyPublicKey, Tap>::parse(script).map_err(JsError::from)?,
+                Miniscript::<XOnlyPublicKey, Tap>::parse(script)
+                    .map_err(WasmMiniscriptError::from)?,
             )),
             "segwitv0" => Ok(WrapMiniscript::from(
-                Miniscript::<PublicKey, Segwitv0>::parse(script).map_err(JsError::from)?,
+                Miniscript::<PublicKey, Segwitv0>::parse(script)
+                    .map_err(WasmMiniscriptError::from)?,
             )),
             "legacy" => Ok(WrapMiniscript::from(
-                Miniscript::<PublicKey, Legacy>::parse(script).map_err(JsError::from)?,
+                Miniscript::<PublicKey, Legacy>::parse(script)
+                    .map_err(WasmMiniscriptError::from)?,
             )),
-            _ => Err(JsError::new("Invalid context type")),
+            _ => Err(WasmMiniscriptError::new("Invalid context type")),
         }
     }
 }