From 437eb7e14e3aacebd17ae99948f0acbe706dd526 Mon Sep 17 00:00:00 2001
From: Otto Allmendinger <otto@bitgo.com>
Date: Mon, 27 Jan 2025 15:30:30 +0100
Subject: [PATCH 1/2] feat(abstract-utxo): extend Tr2Of3 test for
 findDescriptors

The previous test was incomplete as we used Tr2Of3 only for the external output

Issue: BTC-1786
---
 .../test/core/descriptor/psbt/findDescriptors.ts         | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/modules/abstract-utxo/test/core/descriptor/psbt/findDescriptors.ts b/modules/abstract-utxo/test/core/descriptor/psbt/findDescriptors.ts
index 1bc434b02a..8cffd8f762 100644
--- a/modules/abstract-utxo/test/core/descriptor/psbt/findDescriptors.ts
+++ b/modules/abstract-utxo/test/core/descriptor/psbt/findDescriptors.ts
@@ -5,10 +5,10 @@ import { findDescriptorForInput, findDescriptorForOutput } from '../../../../src
 
 import { mockPsbt } from './mock.utils';
 
-function describeWithTemplates(tA: DescriptorTemplate, tB: DescriptorTemplate) {
-  describe(`parsePsbt [${tA},${tB}]`, function () {
-    const descriptorA = getDescriptor(tA, getDefaultXPubs('a'));
-    const descriptorB = getDescriptor(tB, getDefaultXPubs('b'));
+function describeWithTemplates(templateSelf: DescriptorTemplate, templateOther: DescriptorTemplate) {
+  describe(`parsePsbt [${templateSelf},${templateOther}]`, function () {
+    const descriptorA = getDescriptor(templateSelf, getDefaultXPubs('a'));
+    const descriptorB = getDescriptor(templateOther, getDefaultXPubs('b'));
     const descriptorMap = new Map([
       ['a', descriptorA],
       ['b', descriptorB],
@@ -41,3 +41,4 @@ function describeWithTemplates(tA: DescriptorTemplate, tB: DescriptorTemplate) {
 
 describeWithTemplates('Wsh2Of3', 'Wsh2Of3');
 describeWithTemplates('Wsh2Of3', 'Tr2Of3-NoKeyPath');
+describeWithTemplates('Tr2Of3-NoKeyPath', 'Tr2Of3-NoKeyPath');

From 758777c94dbcc6d1008ecc36c11c2d45b2457d1b Mon Sep 17 00:00:00 2001
From: Otto Allmendinger <otto@bitgo.com>
Date: Mon, 27 Jan 2025 15:31:41 +0100
Subject: [PATCH 2/2] fix(abstract-utxo): fix findDescriptorForOutput for
 taproot outputs

Issue: BTC-1786
---
 .../core/descriptor/psbt/findDescriptors.ts   | 40 +++++++++----------
 1 file changed, 20 insertions(+), 20 deletions(-)

diff --git a/modules/abstract-utxo/src/core/descriptor/psbt/findDescriptors.ts b/modules/abstract-utxo/src/core/descriptor/psbt/findDescriptors.ts
index bdd843cf1b..567a98232c 100644
--- a/modules/abstract-utxo/src/core/descriptor/psbt/findDescriptors.ts
+++ b/modules/abstract-utxo/src/core/descriptor/psbt/findDescriptors.ts
@@ -71,6 +71,19 @@ function findDescriptorForAnyDerivationPath(
   return undefined;
 }
 
+type WithBip32Derivation = { bip32Derivation?: { path: string }[] };
+type WithTapBip32Derivation = { tapBip32Derivation?: { path: string }[] };
+
+function getDerivationPaths(v: WithBip32Derivation | WithTapBip32Derivation): string[] | undefined {
+  if ('bip32Derivation' in v && v.bip32Derivation) {
+    return v.bip32Derivation.map((v) => v.path);
+  }
+  if ('tapBip32Derivation' in v && v.tapBip32Derivation) {
+    return v.tapBip32Derivation.map((v) => v.path).filter((v) => v !== '' && v !== 'm');
+  }
+  return undefined;
+}
+
 /**
  * @param input
  * @param descriptorMap
@@ -84,21 +97,11 @@ export function findDescriptorForInput(
   if (!script) {
     throw new Error('Missing script');
   }
-  if (input.bip32Derivation !== undefined) {
-    return findDescriptorForAnyDerivationPath(
-      script,
-      input.bip32Derivation.map((v) => v.path),
-      descriptorMap
-    );
-  }
-  if (input.tapBip32Derivation !== undefined) {
-    return findDescriptorForAnyDerivationPath(
-      script,
-      input.tapBip32Derivation.filter((v) => v.path !== '' && v.path !== 'm').map((v) => v.path),
-      descriptorMap
-    );
+  const derivationPaths = getDerivationPaths(input);
+  if (!derivationPaths) {
+    throw new Error('Missing derivation paths');
   }
-  throw new Error('Missing derivation path');
+  return findDescriptorForAnyDerivationPath(script, derivationPaths, descriptorMap);
 }
 
 /**
@@ -112,12 +115,9 @@ export function findDescriptorForOutput(
   output: PsbtOutput,
   descriptorMap: DescriptorMap
 ): DescriptorWithIndex | undefined {
-  if (!output.bip32Derivation) {
+  const derivationPaths = getDerivationPaths(output);
+  if (!derivationPaths) {
     return undefined;
   }
-  return findDescriptorForAnyDerivationPath(
-    script,
-    output.bip32Derivation.map((d) => d.path),
-    descriptorMap
-  );
+  return findDescriptorForAnyDerivationPath(script, derivationPaths, descriptorMap);
 }