feat: initial support to taproot to update psbt

Author: landabaso

src/descriptors.ts

@@ -307,23 +307,28 @@ export function DescriptorsFactory(ecc: TinySecp256k1Interface) {
       try {
         payment = p2pkh({ output, network });
         isSegwit = false;
+        isTaproot = false;
       } catch (e) {}
       try {
         payment = p2sh({ output, network });
         // It assumes that an addr(SH_ADDRESS) is always a add(SH_WPKH) address
         isSegwit = true;
+        isTaproot = false;
       } catch (e) {}
       try {
         payment = p2wpkh({ output, network });
         isSegwit = true;
+        isTaproot = false;
       } catch (e) {}
       try {
         payment = p2wsh({ output, network });
         isSegwit = true;
+        isTaproot = false;
       } catch (e) {}
       try {
         payment = p2tr({ output, network });
         isSegwit = true;
+        isTaproot = true;
       } catch (e) {}
       if (!payment) {
         throw new Error(`Error: invalid address ${matchedAddress}`);
@@ -332,6 +337,7 @@ export function DescriptorsFactory(ecc: TinySecp256k1Interface) {
     //pk(KEY)
     else if (canonicalExpression.match(RE.rePkAnchored)) {
       isSegwit = false;
+      isTaproot = false;
       const keyExpression = canonicalExpression.match(
         RE.reNonSegwitKeyExp
       )?.[0];
@@ -355,6 +361,7 @@ export function DescriptorsFactory(ecc: TinySecp256k1Interface) {
     //pkh(KEY) - legacy
     else if (canonicalExpression.match(RE.rePkhAnchored)) {
       isSegwit = false;
+      isTaproot = false;
       const keyExpression = canonicalExpression.match(
         RE.reNonSegwitKeyExp
       )?.[0];
@@ -377,6 +384,7 @@ export function DescriptorsFactory(ecc: TinySecp256k1Interface) {
     //sh(wpkh(KEY)) - nested segwit
     else if (canonicalExpression.match(RE.reShWpkhAnchored)) {
       isSegwit = true;
+      isTaproot = false;
       const keyExpression = canonicalExpression.match(RE.reSegwitKeyExp)?.[0];
       if (!keyExpression)
         throw new Error(`Error: keyExpression could not me extracted`);
@@ -402,6 +410,7 @@ export function DescriptorsFactory(ecc: TinySecp256k1Interface) {
     //wpkh(KEY) - native segwit
     else if (canonicalExpression.match(RE.reWpkhAnchored)) {
       isSegwit = true;
+      isTaproot = false;
       const keyExpression = canonicalExpression.match(RE.reSegwitKeyExp)?.[0];
       if (!keyExpression)
         throw new Error(`Error: keyExpression could not me extracted`);
@@ -422,6 +431,7 @@ export function DescriptorsFactory(ecc: TinySecp256k1Interface) {
     //sh(wsh(miniscript))
     else if (canonicalExpression.match(RE.reShWshMiniscriptAnchored)) {
       isSegwit = true;
+      isTaproot = false;
       miniscript = canonicalExpression.match(RE.reShWshMiniscriptAnchored)?.[1]; //[1]-> whatever is found sh(wsh(->HERE<-))
       if (!miniscript)
         throw new Error(`Error: could not get miniscript in ${descriptor}`);
@@ -462,6 +472,7 @@ export function DescriptorsFactory(ecc: TinySecp256k1Interface) {
       //isSegwit false because we know it's a P2SH of a miniscript and not a
       //P2SH that embeds a witness payment.
       isSegwit = false;
+      isTaproot = false;
       miniscript = canonicalExpression.match(RE.reShMiniscriptAnchored)?.[1]; //[1]-> whatever is found sh(->HERE<-)
       if (!miniscript)
         throw new Error(`Error: could not get miniscript in ${descriptor}`);
@@ -505,6 +516,7 @@ export function DescriptorsFactory(ecc: TinySecp256k1Interface) {
     //wsh(miniscript)
     else if (canonicalExpression.match(RE.reWshMiniscriptAnchored)) {
       isSegwit = true;
+      isTaproot = false;
       miniscript = canonicalExpression.match(RE.reWshMiniscriptAnchored)?.[1]; //[1]-> whatever is found wsh(->HERE<-)
       if (!miniscript)
         throw new Error(`Error: could not get miniscript in ${descriptor}`);

src/psbt.ts

@@ -1,7 +1,11 @@
 // Copyright (c) 2023 Jose-Luis Landabaso - https://bitcoinerlab.com
 // Distributed under the MIT software license
 
-import type { PsbtInput, Bip32Derivation } from 'bip174/src/lib/interfaces';
+import type {
+  PsbtInput,
+  Bip32Derivation,
+  TapBip32Derivation
+} from 'bip174/src/lib/interfaces';
 import type { KeyInfo } from './types';
 import {
   payments,
@@ -238,22 +242,43 @@ export function updatePsbt({
     input.nonWitnessUtxo = Transaction.fromHex(txHex).toBuffer();
   }
 
-  const bip32Derivation = keysInfo
-    .filter(
-      (keyInfo: KeyInfo) =>
-        keyInfo.pubkey && keyInfo.masterFingerprint && keyInfo.path
-    )
-    .map((keyInfo: KeyInfo): Bip32Derivation => {
-      const pubkey = keyInfo.pubkey;
-      if (!pubkey)
-        throw new Error(`key ${keyInfo.keyExpression} missing pubkey`);
-      return {
-        masterFingerprint: keyInfo.masterFingerprint!,
-        pubkey,
-        path: keyInfo.path!
-      };
-    });
-  if (bip32Derivation.length) input.bip32Derivation = bip32Derivation;
+  if (isTaproot) {
+    const tapBip32Derivation = keysInfo
+      .filter(
+        (keyInfo: KeyInfo) =>
+          keyInfo.pubkey && keyInfo.masterFingerprint && keyInfo.path
+      )
+      .map((keyInfo: KeyInfo): TapBip32Derivation => {
+        const pubkey = keyInfo.pubkey;
+        if (!pubkey)
+          throw new Error(`key ${keyInfo.keyExpression} missing pubkey`);
+        return {
+          masterFingerprint: keyInfo.masterFingerprint!,
+          pubkey,
+          path: keyInfo.path!,
+          leafHashes: [] // Empty array for basic taproot key spend
+        };
+      });
+    if (tapBip32Derivation.length)
+      input.tapBip32Derivation = tapBip32Derivation;
+  } else {
+    const bip32Derivation = keysInfo
+      .filter(
+        (keyInfo: KeyInfo) =>
+          keyInfo.pubkey && keyInfo.masterFingerprint && keyInfo.path
+      )
+      .map((keyInfo: KeyInfo): Bip32Derivation => {
+        const pubkey = keyInfo.pubkey;
+        if (!pubkey)
+          throw new Error(`key ${keyInfo.keyExpression} missing pubkey`);
+        return {
+          masterFingerprint: keyInfo.masterFingerprint!,
+          pubkey,
+          path: keyInfo.path!
+        };
+      });
+    if (bip32Derivation.length) input.bip32Derivation = bip32Derivation;
+  }
   if (isSegwit && txHex !== undefined) {
     //There's no need to put both witnessUtxo and nonWitnessUtxo
     input.witnessUtxo = { script: scriptPubKey, value };