Merge rust-bitcoin/rust-bitcoin#1031: refactor: remove SchnorrSignatureHash::Reserved variant

69707b0 refactor: remove SchnorrSignatureHash::Reserved variant (eunoia_1729)

Pull request description:

  Resolves #1030

ACKs for top commit:
  sanket1729:
    utACK 69707b0. For reference to other reviewers:
  tcharding:
    ACK 69707b0
  apoelstra:
    ACK 69707b0

Tree-SHA512: d5afe9217e15db8dfd7d712e2fa69d22acda0f93fd7efbc80cf9459303a135a69c8ddf43842584769accb8cffba722ec202dc51f100e0f50262b2561a2fb1699

Author: apoelstra

src/util/psbt/map/input.rs

@@ -162,7 +162,7 @@ pub struct PsbtSighashType {
 impl fmt::Display for PsbtSighashType {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.schnorr_hash_ty() {
-            Ok(SchnorrSighashType::Reserved) | Err(_) => write!(f, "{:#x}", self.inner),
+            Err(_) => write!(f, "{:#x}", self.inner),
             Ok(schnorr_hash_ty) => fmt::Display::fmt(&schnorr_hash_ty, f),
         }
     }
@@ -179,7 +179,6 @@ impl FromStr for PsbtSighashType {
         // inputs. We also do not support SIGHASH_RESERVED in verbatim form
         // ("0xFF" string should be used instead).
         match SchnorrSighashType::from_str(s) {
-            Ok(SchnorrSighashType::Reserved) => return Err(SighashTypeParseError{ unrecognized: s.to_owned() }),
             Ok(ty) => return Ok(ty.into()),
             Err(_) => {}
         }
@@ -579,20 +578,6 @@ mod test {
         }
     }
 
-    #[test]
-    fn psbt_sighash_type_schnorr_notstd() {
-        for (schnorr, schnorr_str) in &[
-            (SchnorrSighashType::Reserved, "0xff"),
-        ] {
-            let sighash = PsbtSighashType::from(*schnorr);
-            let s = format!("{}", sighash);
-            assert_eq!(&s, schnorr_str);
-            let back = PsbtSighashType::from_str(&s).unwrap();
-            assert_eq!(back, sighash);
-            assert_eq!(back.schnorr_hash_ty().unwrap(), *schnorr);
-        }
-    }
-
     #[test]
     fn psbt_sighash_type_notstd() {
         let nonstd = 0xdddddddd;

src/util/sighash.rs

@@ -125,9 +125,6 @@ pub enum SchnorrSighashType {
     NonePlusAnyoneCanPay = 0x82,
     /// 0x83: Sign one output and only this input (see `Single` for what "one output" means).
     SinglePlusAnyoneCanPay = 0x83,
-
-    /// Reserved for future use, `#[non_exhaustive]` is not available with MSRV 1.29.0
-    Reserved = 0xFF,
 }
 serde_string_impl!(SchnorrSighashType, "a SchnorrSighashType data");
 
@@ -141,7 +138,6 @@ impl fmt::Display for SchnorrSighashType {
             SchnorrSighashType::AllPlusAnyoneCanPay => "SIGHASH_ALL|SIGHASH_ANYONECANPAY",
             SchnorrSighashType::NonePlusAnyoneCanPay => "SIGHASH_NONE|SIGHASH_ANYONECANPAY",
             SchnorrSighashType::SinglePlusAnyoneCanPay => "SIGHASH_SINGLE|SIGHASH_ANYONECANPAY",
-            SchnorrSighashType::Reserved => "SIGHASH_RESERVED",
         };
         f.write_str(s)
     }
@@ -159,7 +155,6 @@ impl str::FromStr for SchnorrSighashType {
             "SIGHASH_ALL|SIGHASH_ANYONECANPAY" => Ok(SchnorrSighashType::AllPlusAnyoneCanPay),
             "SIGHASH_NONE|SIGHASH_ANYONECANPAY" => Ok(SchnorrSighashType::NonePlusAnyoneCanPay),
             "SIGHASH_SINGLE|SIGHASH_ANYONECANPAY" => Ok(SchnorrSighashType::SinglePlusAnyoneCanPay),
-            "SIGHASH_RESERVED" => Ok(SchnorrSighashType::Reserved),
             _ => Err(SighashTypeParseError{ unrecognized: s.to_owned() }),
         }
     }
@@ -330,7 +325,6 @@ impl SchnorrSighashType {
             SchnorrSighashType::AllPlusAnyoneCanPay => (SchnorrSighashType::All, true),
             SchnorrSighashType::NonePlusAnyoneCanPay => (SchnorrSighashType::None, true),
             SchnorrSighashType::SinglePlusAnyoneCanPay => (SchnorrSighashType::Single, true),
-            SchnorrSighashType::Reserved => (SchnorrSighashType::Reserved, false),
         }
     }
 
@@ -344,7 +338,6 @@ impl SchnorrSighashType {
             0x81 => Ok(SchnorrSighashType::AllPlusAnyoneCanPay),
             0x82 => Ok(SchnorrSighashType::NonePlusAnyoneCanPay),
             0x83 => Ok(SchnorrSighashType::SinglePlusAnyoneCanPay),
-            0xFF => Ok(SchnorrSighashType::Reserved),
             x => Err(Error::InvalidSighashType(x as u32)),
         }
     }
@@ -1174,7 +1167,6 @@ mod tests {
             ("SIGHASH_ALL|SIGHASH_ANYONECANPAY", SchnorrSighashType::AllPlusAnyoneCanPay),
             ("SIGHASH_NONE|SIGHASH_ANYONECANPAY", SchnorrSighashType::NonePlusAnyoneCanPay),
             ("SIGHASH_SINGLE|SIGHASH_ANYONECANPAY", SchnorrSighashType::SinglePlusAnyoneCanPay),
-            ("SIGHASH_RESERVED", SchnorrSighashType::Reserved),
         ];
         for (s, sht) in sighashtypes {
             assert_eq!(sht.to_string(), s);