feat(abstract-utxo): move signTransaction away from abstract coin

Move signTransaction function to standalone module that doesn't depend on
AbstractUtxoCoin. Move DecodedTransaction type to types.ts to break
dependency cycle.

Issue: BTC-2806

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

Author: OttoAllmendinger

modules/abstract-utxo/src/abstractUtxoCoin.ts

@@ -59,6 +59,7 @@ import { isReplayProtectionUnspent } from './transaction/fixedScript/replayProte
 import { supportedCrossChainRecoveries } from './config';
 import {
   assertValidTransactionRecipient,
+  DecodedTransaction,
   explainTx,
   fromExtendedAddressFormat,
   isScriptRecipient,
@@ -178,9 +179,7 @@ function convertValidationErrorToTxIntentMismatch(
   return txIntentError;
 }
 
-export type DecodedTransaction<TNumber extends number | bigint> =
-  | utxolib.bitgo.UtxoTransaction<TNumber>
-  | utxolib.bitgo.UtxoPsbt;
+export type { DecodedTransaction } from './transaction/types';
 
 export type RootWalletKeys = bitgo.RootWalletKeys;
 

modules/abstract-utxo/src/transaction/fixedScript/index.ts

@@ -3,6 +3,6 @@ export { explainPsbtWasm } from './explainPsbtWasm';
 export { parseTransaction } from './parseTransaction';
 export { CustomChangeOptions } from './parseOutput';
 export { verifyTransaction } from './verifyTransaction';
-export { signTransaction } from './signTransaction';
+export { signTransaction, Musig2Participant } from './signTransaction';
 export * from './sign';
 export * from './replayProtection';

modules/abstract-utxo/src/transaction/fixedScript/signTransaction.ts

@@ -6,12 +6,16 @@ import { bitgo } from '@bitgo/utxo-lib';
 import * as utxolib from '@bitgo/utxo-lib';
 import { isTriple, Triple } from '@bitgo/sdk-core';
 
-import { AbstractUtxoCoin, DecodedTransaction } from '../../abstractUtxoCoin';
+import { DecodedTransaction } from '../types';
 
 import { signAndVerifyPsbt, signAndVerifyWalletTransaction } from './sign';
 
 type RootWalletKeys = bitgo.RootWalletKeys;
 
+export interface Musig2Participant {
+  getMusig2Nonces(psbtHex: string, walletId: string): Promise<{ psbt: string }>;
+}
+
 /**
  * Key Value: Unsigned tx id => PSBT
  * It is used to cache PSBTs with taproot key path (MuSig2) inputs during external express signer is activated.
@@ -23,9 +27,10 @@ type RootWalletKeys = bitgo.RootWalletKeys;
 const PSBT_CACHE = new Map<string, utxolib.bitgo.UtxoPsbt>();
 
 export async function signTransaction<TNumber extends number | bigint>(
-  coin: AbstractUtxoCoin,
+  coin: Musig2Participant,
   tx: DecodedTransaction<TNumber>,
   signerKeychain: BIP32Interface | undefined,
+  network: utxolib.Network,
   params: {
     walletId: string | undefined;
     txInfo: { unspents?: utxolib.bitgo.Unspent<TNumber>[] } | undefined;
@@ -79,7 +84,7 @@ export async function signTransaction<TNumber extends number | bigint>(
         assert(signerKeychain);
         tx.setAllInputsMusig2NonceHD(signerKeychain);
         const response = await coin.getMusig2Nonces(tx.toHex(), params.walletId);
-        tx.combine(bitgo.createPsbtFromHex(response.psbt, coin.network));
+        tx.combine(bitgo.createPsbtFromHex(response.psbt, network));
         break;
     }
   } else {

modules/abstract-utxo/src/transaction/signTransaction.ts

@@ -63,7 +63,7 @@ export async function signTransaction<TNumber extends number | bigint>(
       throw new Error('expected a UtxoPsbt object');
     }
   } else {
-    return fixedScript.signTransaction(coin, tx, getSignerKeychain(params.prv), {
+    return fixedScript.signTransaction(coin, tx, getSignerKeychain(params.prv), coin.network, {
       walletId: params.txPrebuild.walletId,
       txInfo: params.txPrebuild.txInfo,
       isLastSignature: params.isLastSignature ?? false,

modules/abstract-utxo/src/transaction/types.ts

@@ -1,7 +1,13 @@
+import * as utxolib from '@bitgo/utxo-lib';
+
 import type { UtxoNamedKeychains } from '../keychains';
 
 import type { CustomChangeOptions } from './fixedScript';
 
+export type DecodedTransaction<TNumber extends number | bigint> =
+  | utxolib.bitgo.UtxoTransaction<TNumber>
+  | utxolib.bitgo.UtxoPsbt;
+
 export interface BaseOutput<TAmount = string | number> {
   address: string;
   amount: TAmount;