From fdcaa26aab45209772f266b297907ad51ff4e7a1 Mon Sep 17 00:00:00 2001
From: Mahmud Ridwan <m@hjr265.me>
Date: Tue, 23 Jan 2024 20:58:42 +0600
Subject: [PATCH 1/3] Use correct mutex

---
 channel.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/channel.go b/channel.go
index 09ce37e..96ebd0b 100644
--- a/channel.go
+++ b/channel.go
@@ -1826,8 +1826,8 @@ func (ch *Channel) Reject(tag uint64, requeue bool) error {
 // GetNextPublishSeqNo returns the sequence number of the next message to be
 // published, when in confirm mode.
 func (ch *Channel) GetNextPublishSeqNo() uint64 {
-	ch.confirms.m.Lock()
-	defer ch.confirms.m.Unlock()
+	ch.confirms.publishedMut.Lock()
+	defer ch.confirms.publishedMut.Unlock()
 
 	return ch.confirms.published + 1
 }

From 936f704f88301b2888b62c4938edd620cef09a7f Mon Sep 17 00:00:00 2001
From: Mahmud Ridwan <m@hjr265.me>
Date: Tue, 23 Jan 2024 21:21:13 +0600
Subject: [PATCH 2/3] Add test

---
 integration_test.go | 51 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/integration_test.go b/integration_test.go
index f92d788..80ab7b3 100644
--- a/integration_test.go
+++ b/integration_test.go
@@ -2025,6 +2025,57 @@ func TestIntegrationGetNextPublishSeqNo(t *testing.T) {
 	}
 }
 
+func TestIntegrationGetNextPublishSeqNoRace(t *testing.T) {
+	if c := integrationConnection(t, "GetNextPublishSeqNoRace"); c != nil {
+		defer c.Close()
+
+		ch, err := c.Channel()
+		if err != nil {
+			t.Fatalf("channel: %v", err)
+		}
+
+		if err = ch.Confirm(false); err != nil {
+			t.Fatalf("could not confirm")
+		}
+
+		ex := "test-get-next-pub"
+		if err = ch.ExchangeDeclare(ex, "direct", false, false, false, false, nil); err != nil {
+			t.Fatalf("cannot declare %v: got: %v", ex, err)
+		}
+
+		n := ch.GetNextPublishSeqNo()
+		if n != 1 {
+			t.Fatalf("wrong next publish seqence number before any publish, expected: %d, got: %d", 1, n)
+		}
+
+		wg := sync.WaitGroup{}
+
+		wg.Add(2)
+
+		go func() {
+			defer wg.Done()
+			n := ch.GetNextPublishSeqNo()
+			if n <= 0 {
+				t.Fatalf("wrong next publish seqence number, expected: > %d, got: %d", 0, n)
+			}
+		}()
+
+		go func() {
+			defer wg.Done()
+			if err := ch.PublishWithContext(context.TODO(), "test-get-next-pub-seq", "", false, false, Publishing{}); err != nil {
+				t.Fatalf("publish error: %v", err)
+			}
+		}()
+
+		wg.Wait()
+
+		n = ch.GetNextPublishSeqNo()
+		if n != 2 {
+			t.Fatalf("wrong next publish seqence number after 15 publishing, expected: %d, got: %d", 2, n)
+		}
+	}
+}
+
 // https://github.com/rabbitmq/amqp091-go/pull/44
 func TestShouldNotWaitAfterConnectionClosedIssue44(t *testing.T) {
 	conn := integrationConnection(t, "TestShouldNotWaitAfterConnectionClosedIssue44")

From 977c4d20faa7ec9d287741e1016ba760d8ef57d0 Mon Sep 17 00:00:00 2001
From: Mahmud Ridwan <m@hjr265.me>
Date: Tue, 23 Jan 2024 23:28:32 +0600
Subject: [PATCH 3/3] Fix lint issues

---
 integration_test.go | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/integration_test.go b/integration_test.go
index 80ab7b3..50c6507 100644
--- a/integration_test.go
+++ b/integration_test.go
@@ -2049,25 +2049,27 @@ func TestIntegrationGetNextPublishSeqNoRace(t *testing.T) {
 		}
 
 		wg := sync.WaitGroup{}
+		fail := false
 
 		wg.Add(2)
 
 		go func() {
 			defer wg.Done()
-			n := ch.GetNextPublishSeqNo()
-			if n <= 0 {
-				t.Fatalf("wrong next publish seqence number, expected: > %d, got: %d", 0, n)
-			}
+			_ = ch.GetNextPublishSeqNo()
 		}()
 
 		go func() {
 			defer wg.Done()
 			if err := ch.PublishWithContext(context.TODO(), "test-get-next-pub-seq", "", false, false, Publishing{}); err != nil {
-				t.Fatalf("publish error: %v", err)
+				t.Logf("publish error: %v", err)
+				fail = true
 			}
 		}()
 
 		wg.Wait()
+		if fail {
+			t.FailNow()
+		}
 
 		n = ch.GetNextPublishSeqNo()
 		if n != 2 {