feat: compute hash from witness control-block

Author: motorina0

src/payments/p2tr.js

@@ -73,7 +73,14 @@ function p2tr(a, opts) {
   lazy.prop(o, 'hash', () => {
     if (a.hash) return a.hash;
     if (a.scriptsTree) return (0, merkle_1.computeMastRoot)(a.scriptsTree);
-    // todo: compute from witness
+    const w = _witness();
+    if (w && w.length > 1) {
+      const controlBlock = w[w.length - 1];
+      const leafVersion = controlBlock[0] & 0b11111110;
+      const script = w[w.length - 2];
+      const tapLeafHash = (0, types_1.leafHash)(script, leafVersion);
+      return (0, types_1.rootHash)(controlBlock, tapLeafHash);
+    }
     return null;
   });
   lazy.prop(o, 'output', () => {

test/fixtures/p2tr.json

@@ -106,9 +106,10 @@
       "expected": {
         "name": "p2tr",
         "internalPubkey": "a7957acbaaf7b444c53d9e0c9436e8a8a3247fd515095d66ddf6201918b40a36",
-        "pubkey": "a44784d6b2d0159ca57f52e3e6023a4f1960d22c089d019f3656d9e23926dcc9",
-        "address": "bc1p53rcf44j6q2eeftl2t37vq36fuvkp53vpzwsr8ek2mv7ywfxmnysdul78t",
-        "output": "OP_1 a44784d6b2d0159ca57f52e3e6023a4f1960d22c089d019f3656d9e23926dcc9",
+        "pubkey": "1ebe8b90363bd097aa9f352c8b21914e1886bc09fe9e70c09f33ef2d2abdf4bc",
+        "hash": "c5c62d7fc595ba5fbe61602eb1a29e2e4763408fe1e2b161beb7cb3c71ebcad9",
+        "address": "bc1pr6lghypk80gf025lx5kgkgv3fcvgd0qfl608psylx0hj624a7j7qay80rv",
+        "output": "OP_1 1ebe8b90363bd097aa9f352c8b21914e1886bc09fe9e70c09f33ef2d2abdf4bc",
         "signature": null,
         "input": null,
         "witness": [
@@ -133,9 +134,10 @@
       "expected": {
         "name": "p2tr",
         "internalPubkey": "a7957acbaaf7b444c53d9e0c9436e8a8a3247fd515095d66ddf6201918b40a36",
-        "pubkey": "a44784d6b2d0159ca57f52e3e6023a4f1960d22c089d019f3656d9e23926dcc9",
-        "address": "bc1p53rcf44j6q2eeftl2t37vq36fuvkp53vpzwsr8ek2mv7ywfxmnysdul78t",
-        "output": "OP_1 a44784d6b2d0159ca57f52e3e6023a4f1960d22c089d019f3656d9e23926dcc9",
+        "pubkey": "1ebe8b90363bd097aa9f352c8b21914e1886bc09fe9e70c09f33ef2d2abdf4bc",
+        "hash": "c5c62d7fc595ba5fbe61602eb1a29e2e4763408fe1e2b161beb7cb3c71ebcad9",
+        "address": "bc1pr6lghypk80gf025lx5kgkgv3fcvgd0qfl608psylx0hj624a7j7qay80rv",
+        "output": "OP_1 1ebe8b90363bd097aa9f352c8b21914e1886bc09fe9e70c09f33ef2d2abdf4bc",
         "signature": null,
         "input": null,
         "witness": [

ts_src/payments/p2tr.ts

@@ -69,7 +69,14 @@ export function p2tr(a: Payment, opts?: PaymentOpts): Payment {
   lazy.prop(o, 'hash', () => {
     if (a.hash) return a.hash;
     if (a.scriptsTree) return computeMastRoot(a.scriptsTree)
-    // todo: compute from witness
+    const w = _witness()
+    if (w && w.length > 1) {
+      const controlBlock = w[w.length - 1];
+      const leafVersion = controlBlock[0] & 0b11111110;
+      const script = w[w.length - 2];
+      const tapLeafHash = leafHash(script, leafVersion)
+      return rootHash(controlBlock, tapLeafHash)
+    }
     return null
   });
   lazy.prop(o, 'output', () => {
@@ -186,10 +193,9 @@ export function p2tr(a: Payment, opts?: PaymentOpts): Payment {
         if (!internalPubkeyPoint)
           throw new TypeError('Invalid internalPubkey for p2tr witness');
 
-
         const leafVersion = controlBlock[0] & 0b11111110;
         const script = witness[witness.length - 2];
-        
+
         const tapLeafHash = leafHash(script, leafVersion)
         const hash = rootHash(controlBlock, tapLeafHash)