Boards show the server their funding tx, as mainnet now insists

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01M5kFodm9azZJVTQxnkDdKe

2 files changed, 8 insertions, 1 deletions

diff --git a/src/ark/board.js b/src/ark/board.js
index 7544353..4192716 100644
--- a/src/ark/board.js
+++ b/src/ark/board.js
@@ -49,13 +49,18 @@ export function buildBoard({ userPub, serverPub, amountSat, feeSat, expiryHeight
   return { fundingTaproot, exitTaproot, exitTx, sighash };
 }
 
-export async function requestBoardCosign(ark, { amountSat, fundingOutpointRaw, expiryHeight, userPub, pubNonce }) {
+export async function requestBoardCosign(ark, { amountSat, fundingOutpointRaw, expiryHeight, userPub, pubNonce, fundingTxBytes }) {
   const w = pbWriter();
   w.varintField(1, amountSat);
   w.bytesField(2, fundingOutpointRaw);
   w.varintField(3, expiryHeight);
   w.bytesField(4, userPub);
   w.bytesField(5, pubNonce);
+  // Mandatory on mainnet since 0.6.0 (require_board_funding_tx): the server
+  // validates the board outpoint against the funding tx and refuses inputs
+  // that are VTXOs. The txid check ignores witnesses, so the broadcast
+  // (signed) serialization is fine here.
+  if (fundingTxBytes) w.bytesField(6, fundingTxBytes);
   const resp = await grpcCall(ark, 'bark_server.ArkService/RequestBoardCosign', w.finish());
   const out = {};
   for (const { field, value } of pbFields(resp)) {
diff --git a/src/ark/manager.js b/src/ark/manager.js
index a478d19..84c0769 100644
--- a/src/ark/manager.js
+++ b/src/ark/manager.js
@@ -1223,9 +1223,11 @@ export class ArkManager {
         fundingOutpointRaw,
       });
       const nonces = musig2.nonceGen(keys.pubkey, keys.privkey, undefined, board.sighash);
+      const fundingTxHex = await this.chain.getTxHex(action.fundingTxid);
       const cosign = await requestBoardCosign(this.arkUrl, {
         amountSat: action.amountSat, fundingOutpointRaw,
         expiryHeight: action.expiryHeight, userPub: keys.pubkey, pubNonce: nonces.public,
+        fundingTxBytes: fundingTxHex ? hex.decode(fundingTxHex.trim()) : undefined,
       });
       const finalSig = combineBoardSignature({ board, serverCosign: cosign, userNonces: nonces, vtxoKeys: keys, serverPub: this.serverPub });
       action.vtxoBytes = hex.encode(encodeBoardVtxo({