From b837c889dc082ade322abd15b583a030a0feaa34 Mon Sep 17 00:00:00 2001
From: ziggie <ziggie1984@protonmail.com>
Date: Thu, 29 May 2025 10:16:22 +0200
Subject: [PATCH 1/3] itest: add disconnect test

Add a connect/disconnect test when the peers both started up
with the rbf coop close feature.
---
 itest/list_on_test.go            |  4 ++++
 itest/lnd_coop_close_rbf_test.go | 22 ++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/itest/list_on_test.go b/itest/list_on_test.go
index 7263b2451a3..5dacc0b1cf2 100644
--- a/itest/list_on_test.go
+++ b/itest/list_on_test.go
@@ -699,6 +699,10 @@ var allTestCases = []*lntest.TestCase{
 		Name:     "rbf coop close",
 		TestFunc: testCoopCloseRbf,
 	},
+	{
+		Name:     "rbf coop close disconnect",
+		TestFunc: testRBFCoopCloseDisconnect,
+	},
 	{
 		Name:     "bump fee low budget",
 		TestFunc: testBumpFeeLowBudget,
diff --git a/itest/lnd_coop_close_rbf_test.go b/itest/lnd_coop_close_rbf_test.go
index 87033464844..5f8b15d4054 100644
--- a/itest/lnd_coop_close_rbf_test.go
+++ b/itest/lnd_coop_close_rbf_test.go
@@ -131,3 +131,25 @@ func testCoopCloseRbf(ht *lntest.HarnessTest) {
 	aliceClosingTxid := ht.WaitForChannelCloseEvent(aliceCloseStream)
 	ht.AssertTxInBlock(block, aliceClosingTxid)
 }
+
+// testRBFCoopCloseDisconnect tests that when a node disconnects that the node
+// is properly disconnected.
+func testRBFCoopCloseDisconnect(ht *lntest.HarnessTest) {
+	rbfCoopFlags := []string{"--protocol.rbf-coop-close"}
+
+	// To kick things off, we'll create two new nodes, then fund them with
+	// enough coins to make a 50/50 channel.
+	cfgs := [][]string{rbfCoopFlags, rbfCoopFlags}
+	params := lntest.OpenChannelParams{
+		Amt:     btcutil.Amount(1000000),
+		PushAmt: btcutil.Amount(1000000 / 2),
+	}
+	_, nodes := ht.CreateSimpleNetwork(cfgs, params)
+	alice, bob := nodes[0], nodes[1]
+
+	// Make sure the nodes are connected.
+	ht.AssertConnected(alice, bob)
+
+	// Disconnect Bob from Alice.
+	ht.DisconnectNodes(alice, bob)
+}

From e593c9d266643aea85c27d3290164b0821d3d0f4 Mon Sep 17 00:00:00 2001
From: ziggie <ziggie1984@protonmail.com>
Date: Thu, 29 May 2025 10:17:35 +0200
Subject: [PATCH 2/3] brontide: fix peer disconnection issue

In case when the rbf coop close feature was active we would not
properly disconnect the peer.
---
 peer/brontide.go | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/peer/brontide.go b/peer/brontide.go
index 17e9bc40901..43dbcb41934 100644
--- a/peer/brontide.go
+++ b/peer/brontide.go
@@ -3804,18 +3804,28 @@ func (p *Brontide) chanFlushEventSentinel(chanCloser *chancloser.RbfChanCloser,
 	// We'll wait until the channel enters the ChannelFlushing state. We
 	// exit after a success loop. As after the first RBF iteration, the
 	// channel will always be flushed.
-	for newState := range newStateChan {
-		if _, ok := newState.(*chancloser.ChannelFlushing); ok {
-			peerLog.Infof("ChannelPoint(%v): rbf coop "+
-				"close is awaiting a flushed state, "+
-				"registering with link..., ",
-				channel.ChannelPoint())
-
-			// Request the link to send the event once the channel
-			// is flushed. We only need this event sent once, so we
-			// can exit now.
-			link.OnFlushedOnce(sendChanFlushed)
+	for {
+		select {
+		case newState, ok := <-newStateChan:
+			if !ok {
+				return
+			}
+
+			if _, ok := newState.(*chancloser.ChannelFlushing); ok {
+				peerLog.Infof("ChannelPoint(%v): rbf coop "+
+					"close is awaiting a flushed state, "+
+					"registering with link..., ",
+					channel.ChannelPoint())
 
+				// Request the link to send the event once the
+				// channel is flushed. We only need this event
+				// sent once, so we can exit now.
+				link.OnFlushedOnce(sendChanFlushed)
+
+				return
+			}
+
+		case <-p.cg.Done():
 			return
 		}
 	}

From 329c571d5a7e259ee1b03752ce3210fb9c3c10d1 Mon Sep 17 00:00:00 2001
From: ziggie <ziggie1984@protonmail.com>
Date: Wed, 28 May 2025 14:24:00 +0200
Subject: [PATCH 3/3] docs: add release notes

---
 docs/release-notes/release-notes-0.19.1.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/docs/release-notes/release-notes-0.19.1.md b/docs/release-notes/release-notes-0.19.1.md
index 72ea90d41ff..c49ccfd346e 100644
--- a/docs/release-notes/release-notes-0.19.1.md
+++ b/docs/release-notes/release-notes-0.19.1.md
@@ -27,6 +27,10 @@
 - Fixed [a case](https://github.com/lightningnetwork/lnd/pull/9854) where the
   `BumpFee` doesn't give an error response.
 
+- Fixed [a case](https://github.com/lightningnetwork/lnd/pull/9872) where a
+  peer would not disconnect properly when both peers supported the new
+  "rbf-coop-close" feature leaving the peer connection in a borked state.
+
 # New Features
 
 ## Functional Enhancements
@@ -83,3 +87,4 @@
 
 * Elle Mouton
 * Yong Yu
+* Ziggie