From ee883c332fd6a90a0aa465ea440c72c94a056f52 Mon Sep 17 00:00:00 2001
From: yyforyongyu <yy2452@columbia.edu>
Date: Fri, 18 Aug 2023 17:59:47 +0800
Subject: [PATCH] chainntnfs: stop `lnd` when received witness stack is empty

This commit uses `Criticalf` to gracefully stop `lnd` when the received
witness data is empty.
---
 chainntnfs/mempool.go    | 14 +++++++++++---
 chainntnfs/txnotifier.go |  9 ++++++---
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/chainntnfs/mempool.go b/chainntnfs/mempool.go
index 414861f59..4cd181df8 100644
--- a/chainntnfs/mempool.go
+++ b/chainntnfs/mempool.go
@@ -223,11 +223,19 @@ func (m *MempoolNotifier) findRelevantInputs(tx *btcutil.Tx) (inputsWithTx,
 		}
 		watchedInputs[*op] = details
 
+		// Sanity check the witness stack. If it's not empty, continue
+		// to next iteration.
+		if details.HasSpenderWitness() {
+			continue
+		}
+
 		// Return an error if the witness data is not present in the
 		// spending transaction.
-		if !details.HasSpenderWitness() {
-			return nil, ErrEmptyWitnessStack
-		}
+		Log.Criticalf("Found spending tx for outpoint=%v in mempool, "+
+			"but the transaction %v does not have witness",
+			op, details.SpendingTx.TxHash())
+
+		return nil, ErrEmptyWitnessStack
 	}
 
 	return watchedInputs, nil
diff --git a/chainntnfs/txnotifier.go b/chainntnfs/txnotifier.go
index 63c8746d0..f6cd0c1b8 100644
--- a/chainntnfs/txnotifier.go
+++ b/chainntnfs/txnotifier.go
@@ -1305,10 +1305,13 @@ func (n *TxNotifier) updateSpendDetails(spendRequest SpendRequest,
 	// Return an error if the witness data is not present in the spending
 	// transaction.
 	//
-	// TODO(yy): maybe we should do a panic here instead to inform the user
-	// to reindex the bitcoind since it's critical error?
-	// panic("Please re-index your bitcoind...")
+	// NOTE: if the witness stack is empty, we will do a critical log which
+	// shuts down the node.
 	if !details.HasSpenderWitness() {
+		Log.Criticalf("Found spending tx for outpoint=%v, but the "+
+			"transaction %v does not have witness",
+			spendRequest.OutPoint, details.SpendingTx.TxHash())
+
 		return ErrEmptyWitnessStack
 	}