feat(utxo-lib): allow buffer as p2shP2pk key

Accept raw public key buffer in addition to BIP32 key instances when
creating p2shP2pk scripts, which allows for reuse by BCH, BTG and other
forks.

Issue: BTC-2656

Co-authored-by: llm-git <[email protected]>

Author: OttoAllmendinger

modules/utxo-lib/src/testutil/mock.ts

@@ -76,9 +76,12 @@ export function isReplayProtectionUnspent<TNumber extends bigint | number>(
 export function mockReplayProtectionUnspent<TNumber extends number | bigint>(
   network: Network,
   value: TNumber,
-  { key = replayProtectionKeyPair, vout = 0 }: { key?: BIP32Interface; vout?: number } = {}
+  { key = replayProtectionKeyPair, vout = 0 }: { key?: BIP32Interface | Buffer; vout?: number } = {}
 ): UnspentWithPrevTx<TNumber> {
-  const outputScript = createOutputScriptP2shP2pk(key.publicKey).scriptPubKey;
+  if (!Buffer.isBuffer(key)) {
+    key = key.publicKey;
+  }
+  const outputScript = createOutputScriptP2shP2pk(key).scriptPubKey;
   const prevTransaction = mockPrevTx(vout, outputScript, BigInt(value), network);
   return { ...fromOutputWithPrevTx(prevTransaction, vout), value };
 }

modules/utxo-lib/src/testutil/psbt.ts

@@ -86,10 +86,14 @@ export function toUnspent(
   input: Input,
   index: number,
   network: Network,
-  rootWalletKeys: RootWalletKeys
+  rootWalletKeys: RootWalletKeys,
+  { p2shP2pkKey }: { p2shP2pkKey?: Buffer } = {}
 ): Unspent<bigint> {
   if (input.scriptType === 'p2shP2pk') {
-    return mockReplayProtectionUnspent(network, input.value, { key: rootWalletKeys['user'], vout: index });
+    return mockReplayProtectionUnspent(network, input.value, {
+      key: p2shP2pkKey ?? rootWalletKeys['user'],
+      vout: index,
+    });
   } else {
     const chain = getInternalChainCode(input.scriptType === 'taprootKeyPathSpend' ? 'p2trMusig2' : input.scriptType);
     return mockWalletUnspent(network, input.value, {
@@ -177,6 +181,7 @@ export function constructPsbt(
   rootWalletKeys: RootWalletKeys,
   signStage: SignStage,
   params?: {
+    p2shP2pkKey?: Buffer;
     signers?: { signerName: KeyName; cosignerName?: KeyName };
     deterministic?: boolean;
     skipNonWitnessUtxo?: boolean;
@@ -194,14 +199,16 @@ export function constructPsbt(
     addXpubsToPsbt(psbt, rootWalletKeys);
   }
 
-  const unspents = inputs.map((input, i) => toUnspent(input, i, network, rootWalletKeys));
+  const unspents = inputs.map((input, i) =>
+    toUnspent(input, i, network, rootWalletKeys, { p2shP2pkKey: params?.p2shP2pkKey })
+  );
 
   unspents.forEach((u, i) => {
     const { signerName, cosignerName } = signers ? signers : getSigners(inputs[i].scriptType);
     if (isWalletUnspent(u) && cosignerName) {
       addWalletUnspentToPsbt(psbt, u, rootWalletKeys, signerName, cosignerName, { skipNonWitnessUtxo });
     } else {
-      const { redeemScript } = createOutputScriptP2shP2pk(rootWalletKeys.user.publicKey);
+      const { redeemScript } = createOutputScriptP2shP2pk(params?.p2shP2pkKey ?? rootWalletKeys.user.publicKey);
       assert(redeemScript);
       addReplayProtectionUnspentToPsbt(psbt, u, redeemScript, { skipNonWitnessUtxo });
     }