feat: pass through bip32PathsAbsolute flag into bip174 psbt

BG-54756

Author: davidkaplanbitgo

src/psbt.d.ts

@@ -53,9 +53,9 @@ export declare type ValidateSigFunction = (pubkey: Buffer, msghash: Buffer, sign
  */
 export declare class Psbt {
     readonly data: PsbtBase;
-    static fromBase64(data: string, opts?: PsbtOptsOptional): Psbt;
-    static fromHex(data: string, opts?: PsbtOptsOptional): Psbt;
-    static fromBuffer(buffer: Buffer, opts?: PsbtOptsOptional): Psbt;
+    static fromBase64(data: string, opts?: PsbtDeserializeOptsOptional): Psbt;
+    static fromHex(data: string, opts?: PsbtDeserializeOptsOptional): Psbt;
+    static fromBuffer(buffer: Buffer, opts?: PsbtDeserializeOptsOptional): Psbt;
     protected static transactionFromBuffer(buffer: Buffer, _network: Network): Transaction<bigint>;
     private __CACHE;
     private opts;
@@ -112,6 +112,9 @@ interface PsbtOptsOptional {
     network?: Network;
     maximumFeeRate?: number;
 }
+interface PsbtDeserializeOptsOptional extends PsbtOptsOptional {
+    bip32PathsAbsolute?: boolean;
+}
 interface PsbtInputExtended extends PsbtInput, TransactionInput {
 }
 declare type PsbtOutputExtended = PsbtOutputExtendedAddress | PsbtOutputExtendedScript;

src/psbt.js

@@ -100,7 +100,9 @@ class Psbt {
     return this.fromBuffer(buffer, opts);
   }
   static fromBuffer(buffer, opts = {}) {
-    const psbtBase = bip174_1.Psbt.fromBuffer(buffer, transactionFromBuffer);
+    const psbtBase = bip174_1.Psbt.fromBuffer(buffer, transactionFromBuffer, {
+      bip32PathsAbsolute: opts.bip32PathsAbsolute,
+    });
     const psbt = new Psbt(opts, psbtBase);
     checkTxForDupeIns(psbt.__CACHE.__TX, psbt.__CACHE);
     return psbt;

test/psbt.spec.ts

@@ -396,6 +396,30 @@ describe(`Psbt`, () => {
     });
   });
 
+  describe('deserialization', () => {
+    [true, false].forEach((bip32PathsAbsolute: boolean) => {
+      it(`bip32Derivation paths are ${
+        bip32PathsAbsolute ? '' : 'not'
+      } absolute`, async () => {
+        const psbt = Psbt.fromBase64(
+          fixtures.signInputHD.checks[0].shouldSign.psbt,
+          { bip32PathsAbsolute },
+        );
+        const input = psbt.data.inputs[0];
+        assert(input);
+        const bip32Derivations = input.bip32Derivation;
+        assert(bip32Derivations);
+        const bip32Derivation = bip32Derivations[0];
+        assert(bip32Derivation);
+        const pathString = bip32Derivation.path;
+        assert(pathString);
+        const path = pathString.split('/');
+        const bip32PathPrefix = bip32PathsAbsolute ? 'm' : `44'`;
+        assert(path[0] === bip32PathPrefix);
+      });
+    });
+  });
+
   describe('signAllInputsHDAsync', () => {
     fixtures.signInputHD.checks.forEach(f => {
       it(f.description, async () => {

ts_src/psbt.ts

@@ -97,18 +97,26 @@ const DEFAULT_OPTS: PsbtOpts = {
  *   Transaction object. Such as fee rate not being larger than maximumFeeRate etc.
  */
 export class Psbt {
-  static fromBase64(data: string, opts: PsbtOptsOptional = {}): Psbt {
+  static fromBase64(
+    data: string,
+    opts: PsbtDeserializeOptsOptional = {},
+  ): Psbt {
     const buffer = Buffer.from(data, 'base64');
     return this.fromBuffer(buffer, opts);
   }
 
-  static fromHex(data: string, opts: PsbtOptsOptional = {}): Psbt {
+  static fromHex(data: string, opts: PsbtDeserializeOptsOptional = {}): Psbt {
     const buffer = Buffer.from(data, 'hex');
     return this.fromBuffer(buffer, opts);
   }
 
-  static fromBuffer(buffer: Buffer, opts: PsbtOptsOptional = {}): Psbt {
-    const psbtBase = PsbtBase.fromBuffer(buffer, transactionFromBuffer);
+  static fromBuffer(
+    buffer: Buffer,
+    opts: PsbtDeserializeOptsOptional = {},
+  ): Psbt {
+    const psbtBase = PsbtBase.fromBuffer(buffer, transactionFromBuffer, {
+      bip32PathsAbsolute: opts.bip32PathsAbsolute,
+    });
     const psbt = new Psbt(opts, psbtBase);
     checkTxForDupeIns(psbt.__CACHE.__TX, psbt.__CACHE);
     return psbt;
@@ -775,6 +783,10 @@ interface PsbtOptsOptional {
   maximumFeeRate?: number;
 }
 
+interface PsbtDeserializeOptsOptional extends PsbtOptsOptional {
+  bip32PathsAbsolute?: boolean;
+}
+
 interface PsbtOpts {
   network: Network;
   maximumFeeRate: number;