From 05b24946eb504d599a4b9d0faafaea966a0eb447 Mon Sep 17 00:00:00 2001
From: harshit933 <harshitverma933@gmail.com>
Date: Fri, 23 Feb 2024 01:48:59 +0530
Subject: [PATCH] Add the `FromScriptError` for handling errors in `address`

This commit adds the `FromScriptError` struct to handle the errors
while generating address from any script. It includes :
- Unrecognized script error.
- Witness Program error.
- Witness Version error.
---
 bitcoin/src/address/error.rs | 44 ++++++++++++++++++++++++++++++++++++
 bitcoin/src/address/mod.rs   | 10 ++++----
 2 files changed, 49 insertions(+), 5 deletions(-)

diff --git a/bitcoin/src/address/error.rs b/bitcoin/src/address/error.rs
index cbb1cb43..45e5e99b 100644
--- a/bitcoin/src/address/error.rs
+++ b/bitcoin/src/address/error.rs
@@ -73,6 +73,50 @@ impl From<witness_program::Error> for Error {
     fn from(e: witness_program::Error) -> Error { Error::WitnessProgram(e) }
 }
 
+/// Error while generating address from script.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum FromScriptError {
+    /// Script is not a p2pkh, p2sh or witness program.
+    UnrecognizedScript,
+    /// A witness program error.
+    WitnessProgram(witness_program::Error),
+    /// A witness version construction error.
+    WitnessVersion(witness_version::TryFromError),
+}
+
+impl fmt::Display for FromScriptError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        use FromScriptError::*;
+
+        match *self {
+            WitnessVersion(ref e) => write_err!(f, "witness version construction error"; e),
+            WitnessProgram(ref e) => write_err!(f, "witness program error"; e),
+            UnrecognizedScript => write!(f, "script is not a p2pkh, p2sh or witness program"),
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+impl std::error::Error for FromScriptError {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        use FromScriptError::*;
+
+        match self {
+            WitnessVersion(e) => Some(e),
+            WitnessProgram(e) => Some(e),
+            UnrecognizedScript => None,
+        }
+    }
+}
+
+impl From<witness_program::Error> for FromScriptError {
+    fn from(e : witness_program::Error) -> Self { FromScriptError::WitnessProgram(e)}
+}
+
+impl From<witness_version::TryFromError> for FromScriptError {
+    fn from(e: witness_version::TryFromError) -> Self { FromScriptError::WitnessVersion(e) }
+}
+
 /// Address type is either invalid or not supported in rust-bitcoin.
 #[derive(Debug, Clone, PartialEq, Eq)]
 #[non_exhaustive]
diff --git a/bitcoin/src/address/mod.rs b/bitcoin/src/address/mod.rs
index 8d97edab..4059853d 100644
--- a/bitcoin/src/address/mod.rs
+++ b/bitcoin/src/address/mod.rs
@@ -54,7 +54,7 @@ use crate::taproot::TapNodeHash;
 #[rustfmt::skip]                // Keep public re-exports separate.
 #[doc(inline)]
 pub use self::{
-    error::{Error, ParseError, UnknownAddressTypeError, UnknownHrpError},
+    error::{Error, ParseError, UnknownAddressTypeError, UnknownHrpError, FromScriptError},
 };
 
 /// The different types of addresses.
@@ -503,7 +503,7 @@ impl Address {
     pub fn is_spend_standard(&self) -> bool { self.address_type().is_some() }
 
     /// Constructs an [`Address`] from an output script (`scriptPubkey`).
-    pub fn from_script(script: &Script, network: Network) -> Result<Address, Error> {
+    pub fn from_script(script: &Script, network: Network) -> Result<Address, FromScriptError> {
         if script.is_p2pkh() {
             let bytes = script.as_bytes()[3..23].try_into().expect("statically 20B long");
             let hash = PubkeyHash::from_byte_array(bytes);
@@ -519,7 +519,7 @@ impl Address {
             let program = WitnessProgram::new(version, &script.as_bytes()[2..])?;
             Ok(Address::from_witness_program(program, network))
         } else {
-            Err(Error::UnrecognizedScript)
+            Err(FromScriptError::UnrecognizedScript)
         }
     }
 
@@ -1236,13 +1236,13 @@ mod tests {
         .unwrap();
         let invalid_segwitv0_script =
             ScriptBuf::from_hex("001161458e330389cd0437ee9fe3641d70cc18").unwrap();
-        let expected = Err(Error::UnrecognizedScript);
+        let expected = Err(FromScriptError::UnrecognizedScript);
 
         assert_eq!(Address::from_script(&bad_p2wpkh, Network::Bitcoin), expected);
         assert_eq!(Address::from_script(&bad_p2wsh, Network::Bitcoin), expected);
         assert_eq!(
             Address::from_script(&invalid_segwitv0_script, Network::Bitcoin),
-            Err(Error::WitnessProgram(witness_program::Error::InvalidSegwitV0Length(17)))
+            Err(FromScriptError::WitnessProgram(witness_program::Error::InvalidSegwitV0Length(17)))
         );
     }