Remove script_pubkey from DescriptorTrait

In preparation for removing the `DescriptorTrait` move the
`script_pubkey` trait methods onto each individual descriptor. Replaces
the `spk` method. Note that once upon a time `spk` was an infallible
version of `script_pubkey` but now `script_pubkey` is itself infallible
so this patch just renames the `spk` method and removes the trait method.

Author: tcharding

examples/htlc.rs

@@ -53,7 +53,7 @@ fn main() {
 
     // Get the scriptPpubkey for this Wsh descriptor.
     assert_eq!(
-        format!("{:x}", htlc_descriptor.spk()),
+        format!("{:x}", htlc_descriptor.script_pubkey()),
         "0020d853877af928a8d2a569c9c0ed14bd16f6a80ce9cccaf8a6150fd8f7f8867ae2"
     );
 

examples/parse.rs

@@ -44,7 +44,7 @@ fn main() {
     // us to call infallible methods for getting script pubkey.
     if let Descriptor::Wsh(wsh) = &desc {
         assert_eq!(
-            format!("{:x}", wsh.spk()),
+            format!("{:x}", wsh.script_pubkey()),
             "0020daef16dd7c946a3e735a6e43310cb2ce33dfd14a04f76bf8241a16654cb2f0f9"
         );
     }

src/descriptor/bare.rs

@@ -69,22 +69,21 @@ impl<Pk: MiniscriptKey> Bare<Pk> {
 }
 
 impl<Pk: MiniscriptKey + ToPublicKey> Bare<Pk> {
-    /// Obtain the corresponding script pubkey for this descriptor
-    /// Non failing verion of [`DescriptorTrait::script_pubkey`] for this descriptor
-    pub fn spk(&self) -> Script {
+    /// Obtains the corresponding script pubkey for this descriptor.
+    pub fn script_pubkey(&self) -> Script {
         self.ms.encode()
     }
 
     /// Obtain the underlying miniscript for this descriptor
     /// Non failing verion of [`DescriptorTrait::explicit_script`] for this descriptor
     pub fn inner_script(&self) -> Script {
-        self.spk()
+        self.script_pubkey()
     }
 
     /// Obtain the pre bip-340 signature script code for this descriptor
     /// Non failing verion of [`DescriptorTrait::script_code`] for this descriptor
     pub fn ecdsa_sighash_script_code(&self) -> Script {
-        self.spk()
+        self.script_pubkey()
     }
 }
 
@@ -139,13 +138,6 @@ where
 }
 
 impl<Pk: MiniscriptKey> DescriptorTrait<Pk> for Bare<Pk> {
-    fn script_pubkey(&self) -> Script
-    where
-        Pk: ToPublicKey,
-    {
-        self.spk()
-    }
-
     fn unsigned_script_sig(&self) -> Script
     where
         Pk: ToPublicKey,
@@ -249,10 +241,11 @@ impl<Pk: MiniscriptKey> Pkh<Pk> {
 }
 
 impl<Pk: MiniscriptKey + ToPublicKey> Pkh<Pk> {
-    /// Obtain the corresponding script pubkey for this descriptor
-    /// Non failing verion of [`DescriptorTrait::script_pubkey`] for this descriptor
-    pub fn spk(&self) -> Script {
-        let addr = Address::p2pkh(&self.pk.to_public_key(), Network::Bitcoin);
+    /// Obtains the corresponding script pubkey for this descriptor.
+    pub fn script_pubkey(&self) -> Script {
+        // Fine to hard code the `Network` here because we immediately call
+        // `script_pubkey` which does not use the `network` field of `Address`.
+        let addr = self.address(Network::Bitcoin);
         addr.script_pubkey()
     }
 
@@ -264,13 +257,13 @@ impl<Pk: MiniscriptKey + ToPublicKey> Pkh<Pk> {
     /// Obtain the underlying miniscript for this descriptor
     /// Non failing verion of [`DescriptorTrait::explicit_script`] for this descriptor
     pub fn inner_script(&self) -> Script {
-        self.spk()
+        self.script_pubkey()
     }
 
     /// Obtain the pre bip-340 signature script code for this descriptor
     /// Non failing verion of [`DescriptorTrait::script_code`] for this descriptor
     pub fn ecdsa_sighash_script_code(&self) -> Script {
-        self.spk()
+        self.script_pubkey()
     }
 }
 
@@ -333,13 +326,6 @@ where
 }
 
 impl<Pk: MiniscriptKey> DescriptorTrait<Pk> for Pkh<Pk> {
-    fn script_pubkey(&self) -> Script
-    where
-        Pk: ToPublicKey,
-    {
-        self.spk()
-    }
-
     fn unsigned_script_sig(&self) -> Script
     where
         Pk: ToPublicKey,

src/descriptor/mod.rs

@@ -76,11 +76,6 @@ pub type KeyMap = HashMap<DescriptorPublicKey, DescriptorSecretKey>;
 // because of traits cannot know underlying generic of Self.
 // Thus, we must implement additional trait for translate function
 pub trait DescriptorTrait<Pk: MiniscriptKey> {
-    /// Computes the scriptpubkey of the descriptor
-    fn script_pubkey(&self) -> Script
-    where
-        Pk: ToPublicKey;
-
     /// Computes the scriptSig that will be in place for an unsigned
     /// input spending an output with this descriptor. For pre-segwit
     /// descriptors, which use the scriptSig for signatures, this
@@ -416,6 +411,18 @@ impl<Pk: MiniscriptKey + ToPublicKey> Descriptor<Pk> {
             Descriptor::Tr(ref tr) => Ok(tr.address(network)),
         }
     }
+
+    /// Computes the scriptpubkey of the descriptor.
+    pub fn script_pubkey(&self) -> Script {
+        match *self {
+            Descriptor::Bare(ref bare) => bare.script_pubkey(),
+            Descriptor::Pkh(ref pkh) => pkh.script_pubkey(),
+            Descriptor::Wpkh(ref wpkh) => wpkh.script_pubkey(),
+            Descriptor::Wsh(ref wsh) => wsh.script_pubkey(),
+            Descriptor::Sh(ref sh) => sh.script_pubkey(),
+            Descriptor::Tr(ref tr) => tr.script_pubkey(),
+        }
+    }
 }
 
 impl<P, Q> TranslatePk<P, Q> for Descriptor<P>
@@ -449,21 +456,6 @@ where
 }
 
 impl<Pk: MiniscriptKey> DescriptorTrait<Pk> for Descriptor<Pk> {
-    /// Computes the scriptpubkey of the descriptor
-    fn script_pubkey(&self) -> Script
-    where
-        Pk: ToPublicKey,
-    {
-        match *self {
-            Descriptor::Bare(ref bare) => bare.script_pubkey(),
-            Descriptor::Pkh(ref pkh) => pkh.script_pubkey(),
-            Descriptor::Wpkh(ref wpkh) => wpkh.script_pubkey(),
-            Descriptor::Wsh(ref wsh) => wsh.script_pubkey(),
-            Descriptor::Sh(ref sh) => sh.script_pubkey(),
-            Descriptor::Tr(ref tr) => tr.script_pubkey(),
-        }
-    }
-
     /// Computes the scriptSig that will be in place for an unsigned
     /// input spending an output with this descriptor. For pre-segwit
     /// descriptors, which use the scriptSig for signatures, this

src/descriptor/segwitv0.rs

@@ -86,9 +86,8 @@ impl<Pk: MiniscriptKey> Wsh<Pk> {
 }
 
 impl<Pk: MiniscriptKey + ToPublicKey> Wsh<Pk> {
-    /// Obtain the corresponding script pubkey for this descriptor
-    /// Non failing verion of [`DescriptorTrait::script_pubkey`] for this descriptor
-    pub fn spk(&self) -> Script {
+    /// Obtains the corresponding script pubkey for this descriptor.
+    pub fn script_pubkey(&self) -> Script {
         self.inner_script().to_v0_p2wsh()
     }
 
@@ -197,13 +196,6 @@ where
 }
 
 impl<Pk: MiniscriptKey> DescriptorTrait<Pk> for Wsh<Pk> {
-    fn script_pubkey(&self) -> Script
-    where
-        Pk: ToPublicKey,
-    {
-        self.spk()
-    }
-
     fn unsigned_script_sig(&self) -> Script
     where
         Pk: ToPublicKey,
@@ -356,9 +348,8 @@ impl<Pk: MiniscriptKey> Wpkh<Pk> {
 }
 
 impl<Pk: MiniscriptKey + ToPublicKey> Wpkh<Pk> {
-    /// Obtain the corresponding script pubkey for this descriptor
-    /// Non failing verion of [`DescriptorTrait::script_pubkey`] for this descriptor
-    pub fn spk(&self) -> Script {
+    /// Obtains the corresponding script pubkey for this descriptor.
+    pub fn script_pubkey(&self) -> Script {
         let addr = Address::p2wpkh(&self.pk.to_public_key(), Network::Bitcoin)
             .expect("wpkh descriptors have compressed keys");
         addr.script_pubkey()
@@ -373,7 +364,7 @@ impl<Pk: MiniscriptKey + ToPublicKey> Wpkh<Pk> {
     /// Obtain the underlying miniscript for this descriptor
     /// Non failing verion of [`DescriptorTrait::explicit_script`] for this descriptor
     pub fn inner_script(&self) -> Script {
-        self.spk()
+        self.script_pubkey()
     }
 
     /// Obtain the pre bip-340 signature script code for this descriptor
@@ -447,13 +438,6 @@ where
 }
 
 impl<Pk: MiniscriptKey> DescriptorTrait<Pk> for Wpkh<Pk> {
-    fn script_pubkey(&self) -> Script
-    where
-        Pk: ToPublicKey,
-    {
-        self.spk()
-    }
-
     fn unsigned_script_sig(&self) -> Script
     where
         Pk: ToPublicKey,

src/descriptor/sh.rs

@@ -217,12 +217,11 @@ impl<Pk: MiniscriptKey> Sh<Pk> {
 }
 
 impl<Pk: MiniscriptKey + ToPublicKey> Sh<Pk> {
-    /// Obtain the corresponding script pubkey for this descriptor
-    /// Non failing verion of [`DescriptorTrait::script_pubkey`] for this descriptor
-    pub fn spk(&self) -> Script {
+    /// Obtains the corresponding script pubkey for this descriptor.
+    pub fn script_pubkey(&self) -> Script {
         match self.inner {
-            ShInner::Wsh(ref wsh) => wsh.spk().to_p2sh(),
-            ShInner::Wpkh(ref wpkh) => wpkh.spk().to_p2sh(),
+            ShInner::Wsh(ref wsh) => wsh.script_pubkey().to_p2sh(),
+            ShInner::Wpkh(ref wpkh) => wpkh.script_pubkey().to_p2sh(),
             ShInner::SortedMulti(ref smv) => smv.encode().to_p2sh(),
             ShInner::Ms(ref ms) => ms.encode().to_p2sh(),
         }
@@ -254,7 +253,7 @@ impl<Pk: MiniscriptKey + ToPublicKey> Sh<Pk> {
     pub fn inner_script(&self) -> Script {
         match self.inner {
             ShInner::Wsh(ref wsh) => wsh.inner_script(),
-            ShInner::Wpkh(ref wpkh) => wpkh.spk(),
+            ShInner::Wpkh(ref wpkh) => wpkh.script_pubkey(),
             ShInner::SortedMulti(ref smv) => smv.encode(),
             ShInner::Ms(ref ms) => ms.encode(),
         }
@@ -276,13 +275,6 @@ impl<Pk: MiniscriptKey + ToPublicKey> Sh<Pk> {
 }
 
 impl<Pk: MiniscriptKey> DescriptorTrait<Pk> for Sh<Pk> {
-    fn script_pubkey(&self) -> Script
-    where
-        Pk: ToPublicKey,
-    {
-        self.spk()
-    }
-
     fn unsigned_script_sig(&self) -> Script
     where
         Pk: ToPublicKey,
@@ -296,7 +288,7 @@ impl<Pk: MiniscriptKey> DescriptorTrait<Pk> for Sh<Pk> {
                     .into_script()
             }
             ShInner::Wpkh(ref wpkh) => {
-                let redeem_script = wpkh.spk();
+                let redeem_script = wpkh.script_pubkey();
                 script::Builder::new()
                     .push_slice(&redeem_script[..])
                     .into_script()

src/descriptor/tr.rs

@@ -281,9 +281,8 @@ impl<Pk: MiniscriptKey> Tr<Pk> {
 }
 
 impl<Pk: MiniscriptKey + ToPublicKey> Tr<Pk> {
-    /// Obtain the corresponding script pubkey for this descriptor
-    /// Same as[`DescriptorTrait::script_pubkey`] for this descriptor
-    pub fn spk(&self) -> Script {
+    /// Obtains the corresponding script pubkey for this descriptor.
+    pub fn script_pubkey(&self) -> Script {
         let output_key = self.spend_info().output_key();
         let builder = bitcoin::blockdata::script::Builder::new();
         builder
@@ -555,13 +554,6 @@ impl<Pk: MiniscriptKey> Liftable<Pk> for Tr<Pk> {
 }
 
 impl<Pk: MiniscriptKey> DescriptorTrait<Pk> for Tr<Pk> {
-    fn script_pubkey(&self) -> Script
-    where
-        Pk: ToPublicKey,
-    {
-        self.spk()
-    }
-
     fn unsigned_script_sig(&self) -> Script
     where
         Pk: ToPublicKey,

src/psbt/mod.rs

@@ -34,8 +34,8 @@ use crate::miniscript::iter::PkPkh;
 use crate::miniscript::limits::SEQUENCE_LOCKTIME_DISABLE_FLAG;
 use crate::miniscript::satisfy::{After, Older};
 use crate::{
-    descriptor, interpreter, Descriptor, DescriptorPublicKey, DescriptorTrait, MiniscriptKey,
-    Preimage32, Satisfier, ToPublicKey, TranslatePk, TranslatePk2,
+    descriptor, interpreter, Descriptor, DescriptorPublicKey, MiniscriptKey, Preimage32, Satisfier,
+    ToPublicKey, TranslatePk, TranslatePk2,
 };
 
 mod finalizer;
@@ -1152,6 +1152,7 @@ mod tests {
     use bitcoin::{OutPoint, TxIn, TxOut, XOnlyPublicKey};
 
     use super::*;
+    use crate::descriptor::DescriptorTrait;
     use crate::Miniscript;
 
     #[test]