Fix psbt parsing and tap_bip32_derivation. Closes gh-100, gh-101

src/index.ts

@@ -14,7 +14,7 @@ export {
 } from './payment.js';
 // prettier-ignore
 export {
-  OP, RawTx, CompactSize,
+  OP, RawTx, CompactSize, RawWitness,
   Script, ScriptNum, ScriptType, MAX_SCRIPT_BYTE_LENGTH,
 } from './script.js';
 export { Transaction } from './transaction.js';

src/psbt.ts

@@ -1,6 +1,7 @@
 import { hex } from '@scure/base';
 import * as P from 'micro-packed';
-import { CompactSize, CompactSizeLen, RawOutput, RawTx, RawWitness, VarBytes } from './script.js';
+import { CompactSize, CompactSizeLen, VarBytes } from './script.js';
+import { RawOutput, RawTx, RawOldTx, RawWitness } from './script.js';
 import { Transaction } from './transaction.js'; // circular
 import { Bytes, compareBytes, PubT, validatePubkey, equalBytes } from './utils.js';
 
@@ -60,7 +61,7 @@ const Bytes32 = P.bytes(32);
 // Tables from BIP-0174 (https://github.com/bitcoin/bips/blob/master/bip-0174.mediawiki)
 // prettier-ignore
 export const PSBTGlobal = {
-  unsignedTx:       [0x00, false,      RawTx,          [0], [0],    false],
+  unsignedTx:       [0x00, false,      RawOldTx,          [0], [0],    false],
   xpub:             [0x01, GlobalXPUB, BIP32Der,       [],  [0, 2], false],
   txVersion:        [0x02, false,      P.U32LE,        [2], [2],    false],
   fallbackLocktime: [0x03, false,      P.U32LE,        [],  [2],    false],
@@ -342,8 +343,6 @@ const PSBTGlobalCoder = P.validate(PSBTKeyMap(PSBTGlobal), (g) => {
   const version = g.version || 0;
   if (version === 0) {
     if (!g.unsignedTx) throw new Error('PSBTv0: missing unsignedTx');
-    if (g.unsignedTx.segwitFlag || g.unsignedTx.witnesses)
-      throw new Error('PSBTv0: witness in unsingedTx');
     for (const inp of g.unsignedTx.inputs)
       if (inp.finalScriptSig && inp.finalScriptSig.length)
         throw new Error('PSBTv0: input scriptSig found in unsignedTx');

src/script.ts

@@ -236,3 +236,10 @@ function validateRawTx(tx: P.UnwrapCoder<typeof _RawTx>) {
   return tx;
 }
 export const RawTx = P.validate(_RawTx, validateRawTx);
+// Pre-SegWit serialization format (for PSBTv0)
+export const RawOldTx = P.struct({
+  version: P.I32LE,
+  inputs: BTCArray(RawInput),
+  outputs: BTCArray(RawOutput),
+  lockTime: P.U32LE,
+});

src/transaction.ts

@@ -1,9 +1,9 @@
 import * as P from 'micro-packed';
 import { hex } from '@scure/base';
-
 import { Address, CustomScript, OutScript, checkScript, tapLeafHash } from './payment.js';
 import * as psbt from './psbt.js'; // circular
-import { CompactSizeLen, RawOutput, RawTx, RawWitness, Script, VarBytes } from './script.js';
+import { CompactSizeLen, Script, VarBytes } from './script.js';
+import { RawOutput, RawTx, RawOldTx, RawWitness } from './script.js';
 import { NETWORK, Bytes, concatBytes, isBytes, equalBytes } from './utils.js';
 import * as u from './utils.js';
 import { getInputType, toVsize, normalizeInput, getPrevOut } from './utxo.js'; // circular
@@ -284,6 +284,11 @@ export class Transaction {
   toPSBT(PSBTVersion = this.opts.PSBTVersion) {
     if (PSBTVersion !== 0 && PSBTVersion !== 2)
       throw new Error(`Wrong PSBT version=${PSBTVersion}`);
+    // if (PSBTVersion === 0 && this.inputs.length === 0) {
+    //   throw new Error(
+    //     'PSBT version=0 export for transaction without inputs disabled, please use version=2. Please check `toPSBT` method for explanation.'
+    //   );
+    // }
     const inputs = this.inputs.map((i) => psbt.cleanPSBTFields(PSBTVersion, psbt.PSBTInput, i));
     for (const inp of inputs) {
       // Don't serialize empty fields
@@ -294,7 +299,23 @@ export class Transaction {
     const outputs = this.outputs.map((i) => psbt.cleanPSBTFields(PSBTVersion, psbt.PSBTOutput, i));
     const global = { ...this.global };
     if (PSBTVersion === 0) {
-      global.unsignedTx = RawTx.decode(this.unsignedTx);
+      /*
+      - Bitcoin raw transaction expects to have at least 1 input because it uses case with zero inputs as marker for SegWit
+      - this means we cannot serialize raw tx with zero inputs since it will be parsed as SegWit tx
+      - Parsing of PSBTv0 depends on unsignedTx (it looks for input count here)
+      - BIP-174 requires old serialization format (without witnesses) inside global, which solves this
+      */
+      global.unsignedTx = RawOldTx.decode(
+        RawOldTx.encode({
+          version: this.version,
+          lockTime: this.lockTime,
+          inputs: this.inputs.map(inputBeforeSign).map((i) => ({
+            ...i,
+            finalScriptSig: P.EMPTY,
+          })),
+          outputs: this.outputs.map(outputBeforeSign),
+        })
+      );
       delete global.fallbackLocktime;
       delete global.txVersion;
     } else {
@@ -744,7 +765,6 @@ export class Transaction {
     // Taproot
     const prevOut = getPrevOut(input);
     if (inputType.txType === 'taproot') {
-      if (input.tapBip32Derivation) throw new Error('tapBip32Derivation unsupported');
       const prevOuts = this.inputs.map(getPrevOut);
       const prevOutScript = prevOuts.map((i) => i.script);
       const amount = prevOuts.map((i) => i.amount);
@@ -1030,8 +1050,10 @@ export class Transaction {
         );
       }
     }
-    const thisUnsigned = this.global.unsignedTx ? RawTx.encode(this.global.unsignedTx) : P.EMPTY;
-    const otherUnsigned = other.global.unsignedTx ? RawTx.encode(other.global.unsignedTx) : P.EMPTY;
+    const thisUnsigned = this.global.unsignedTx ? RawOldTx.encode(this.global.unsignedTx) : P.EMPTY;
+    const otherUnsigned = other.global.unsignedTx
+      ? RawOldTx.encode(other.global.unsignedTx)
+      : P.EMPTY;
     if (!equalBytes(thisUnsigned, otherUnsigned))
       throw new Error(`Transaction/combine: different unsigned tx`);
     this.global = psbt.mergeKeyMap(psbt.PSBTGlobal, this.global, other.global);

test/basic.test.js

@@ -1871,6 +1871,121 @@ should('getOutputAddress', () => {
   }
 });
 
+should('GH-100: end-of-buffer psbt', () => {
+  const psbt = new btc.Transaction();
+  psbt.addOutput({
+    amount: BigInt(10000),
+    script: hex.decode('51203701d8f81bf26a07eebef592f2960e4b6db32b09fce20246db0842ebfc45001b'),
+  });
+
+  const decoded2 = btc.Transaction.fromPSBT(psbt.toPSBT(2));
+  deepStrictEqual(decoded2.inputs, psbt.inputs);
+  deepStrictEqual(decoded2.outputs, psbt.outputs);
+
+  const decoded0 = btc.Transaction.fromPSBT(psbt.toPSBT(0));
+  deepStrictEqual(decoded0.inputs, psbt.inputs);
+  deepStrictEqual(decoded0.outputs, psbt.outputs);
+  // ./bin/bitcoin-cli createpsbt [] '[{"bc1pxuqa37qm7f4q0m477kf099swfdkmx2cfln3qy3kmpppwhlz9qqdsre4trt":0.00010000}]'
+  const corePsbt = base64.decode(
+    'cHNidP8BADUCAAAAAAEQJwAAAAAAACJRIDcB2Pgb8moH7r71kvKWDkttsysJ/OICRtsIQuv8RQAbAAAAAAAA'
+  );
+  deepStrictEqual(psbt.toPSBT(0), corePsbt);
+  // ./bin/bitcoin-cli createpsbt [] []
+  const coreEmpty = base64.decode('cHNidP8BAAoCAAAAAAAAAAAAAA==');
+  deepStrictEqual(new btc.Transaction().toPSBT(0), coreEmpty);
+  // NOTE: bitcoinjs does very strange things (including silently fallback into PSBTv2) and generates non-valid PSBT which
+  // cannot be parsed by bitcoin-cli
+});
+
+should('GH-101: TAP_BIP32_DERIVATION', () => {
+  const opts = {};
+  const privKey = hex.decode('0101010101010101010101010101010101010101010101010101010101010101');
+  // setup taproot tx
+  const pubS = secp256k1_schnorr.getPublicKey(privKey);
+  const tx = new btc.Transaction(opts);
+  for (const inp of TX_TEST_INPUTS) {
+    const tr = btc.p2tr(pubS);
+    tx.addInput({
+      ...inp,
+      ...tr,
+      witnessUtxo: { script: tr.script, amount: inp.amount },
+    });
+  }
+  const txWithtapBip32 = btc.Transaction.fromPSBT(
+    hex.decode(
+      '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'
+    )
+  );
+  tx.updateInput(0, {
+    tapBip32Derivation: txWithtapBip32.inputs[0].tapBip32Derivation,
+  });
+  // 'tapBip32Derivation' can be added
+  deepStrictEqual(tx.inputs[0], {
+    txid: hex.decode('c061c23190ed3370ad5206769651eaf6fac6d87d85b5db34e30a74e0c4a6da3e'),
+    index: 0,
+    sequence: 4294967295,
+    tapInternalKey: hex.decode('1b84c5567b126440995d3ed5aaba0565d71e1834604819ff9c17f5e9d5dd078f'),
+    witnessUtxo: {
+      script: hex.decode('51208c5db7f797196d6edc4dd7df6048f4ea6b883a6af6af032342088f436543790f'),
+      amount: 550n,
+    },
+    tapBip32Derivation: [
+      [
+        hex.decode('fe349064c98d6e2a853fa3c9b12bd8b304a19c195c60efa7ee2393046d3fa232'),
+        {
+          hashes: [],
+          der: { fingerprint: 1999318439, path: [2147483734, 2147483649, 2147483648, 1, 0] },
+        },
+      ],
+    ],
+  });
+  // 'tapBip32Derivation' can be removed
+  tx.updateInput(0, {
+    tapBip32Derivation: undefined,
+  });
+  deepStrictEqual(tx.inputs[0], {
+    txid: hex.decode('c061c23190ed3370ad5206769651eaf6fac6d87d85b5db34e30a74e0c4a6da3e'),
+    index: 0,
+    sequence: 4294967295,
+    tapInternalKey: hex.decode('1b84c5567b126440995d3ed5aaba0565d71e1834604819ff9c17f5e9d5dd078f'),
+    witnessUtxo: {
+      script: hex.decode('51208c5db7f797196d6edc4dd7df6048f4ea6b883a6af6af032342088f436543790f'),
+      amount: 550n,
+    },
+  });
+  // re-add & sign
+  tx.updateInput(0, {
+    tapBip32Derivation: txWithtapBip32.inputs[0].tapBip32Derivation,
+  });
+  deepStrictEqual(tx.inputs[0], {
+    txid: hex.decode('c061c23190ed3370ad5206769651eaf6fac6d87d85b5db34e30a74e0c4a6da3e'),
+    index: 0,
+    sequence: 4294967295,
+    tapInternalKey: hex.decode('1b84c5567b126440995d3ed5aaba0565d71e1834604819ff9c17f5e9d5dd078f'),
+    witnessUtxo: {
+      script: hex.decode('51208c5db7f797196d6edc4dd7df6048f4ea6b883a6af6af032342088f436543790f'),
+      amount: 550n,
+    },
+    tapBip32Derivation: [
+      [
+        hex.decode('fe349064c98d6e2a853fa3c9b12bd8b304a19c195c60efa7ee2393046d3fa232'),
+        {
+          hashes: [],
+          der: { fingerprint: 1999318439, path: [2147483734, 2147483649, 2147483648, 1, 0] },
+        },
+      ],
+    ],
+  });
+  // Should be same as without field
+  for (const [address, amount] of TX_TEST_OUTPUTS) tx.addOutputAddress(address, amount);
+  tx.sign(privKey, undefined, new Uint8Array(32));
+  tx.finalize();
+  deepStrictEqual(
+    hex.encode(tx.extract()),
+    '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'
+  );
+});
+
 // ESM is broken.
 import url from 'node:url';
 if (import.meta.url === url.pathToFileURL(process.argv[1]).href) {

test/bitcoinjs-test/btcjs-taproot.test.js

@@ -33,7 +33,7 @@ should(`PSBT P2TR finalizeInput`, () => {
   // Remove signatures for leaf's we don't want to finalize
   if (tx.inputs[t.index].tapScriptSig) {
     tx.inputs[t.index].tapScriptSig = tx.inputs[t.index].tapScriptSig.filter((i) =>
-      P.equalBytes(i[0].leafHash, hex.decode(t.leafHash))
+      P.utils.equalBytes(i[0].leafHash, hex.decode(t.leafHash))
     );
   }
   tx.finalize();

test/slow.test.js

@@ -12,7 +12,7 @@ should('big multisig (ours)', () => {
   const regtest = { bech32: 'bcrt', pubKeyHash: 0x6f, scriptHash: 0xc4 };
 
   const pkeys = [];
-  for (let i = 1; i < 1000; i++) pkeys.push(P.U256BE.encode(i));
+  for (let i = 1; i < 1000; i++) pkeys.push(P.U256BE.encode(BigInt(i)));
 
   const pubs = pkeys.map(secp256k1_schnorr.getPublicKey);
   const spend = btc.p2tr(undefined, btc.p2tr_ms(999, pubs), regtest);