From 728bc1e37bfb13c62fdd6cf872c047b205c41e14 Mon Sep 17 00:00:00 2001
From: Jarema <melgaer@gmail.com>
Date: Sat, 19 Jun 2021 19:19:14 +0200
Subject: [PATCH 1/3] Alias NextMsg to Fetch for Pull Subscribers

---
 nats.go | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/nats.go b/nats.go
index 5f4ddf5e9..9ae73b92f 100644
--- a/nats.go
+++ b/nats.go
@@ -3911,7 +3911,14 @@ func (s *Subscription) NextMsg(timeout time.Duration) (*Msg, error) {
 	if s == nil {
 		return nil, ErrBadSubscription
 	}
-
+	// In case of Pull Subscription, alias NextMsg to Fetch
+	if s.typ == PullSubscription {
+		msgs, err := s.Fetch(1, MaxWait(timeout))
+		if err != nil {
+			return nil, err
+		}
+		return msgs[0], nil
+	}
 	s.mu.Lock()
 	err := s.validateNextMsgState()
 	if err != nil {

From f452241c065fec7505d5b7380f6402a063312cb4 Mon Sep 17 00:00:00 2001
From: Jarema <melgaer@gmail.com>
Date: Sat, 19 Jun 2021 21:31:32 +0200
Subject: [PATCH 2/3] Add test for NextMsg as Fetch alias in Pull Subscribe

---
 test/js_test.go | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/test/js_test.go b/test/js_test.go
index a9367f698..7335af3f9 100644
--- a/test/js_test.go
+++ b/test/js_test.go
@@ -526,6 +526,19 @@ func TestJetStreamSubscribe(t *testing.T) {
 		t.Fatalf("Unexpected error: %v", err)
 	}
 
+	// Test the NextMsg Alias for Fetch
+	nmsg, err := sub.NextMsg(time.Second * 1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if info, _ := sub.ConsumerInfo(); info.NumAckPending != 1 || info.NumPending != uint64(toSend-1) {
+		t.Fatalf("Expected %d pending ack, and %d still waiting to be delivered, got %d and %d", 1, 1, info.NumAckPending, info.NumPending)
+	}
+
+	if err := nmsg.Nak(); err != nil {
+		t.Fatal(err)
+	}
+
 	// The first batch if available should be delivered and queued up.
 	bmsgs, err := sub.Fetch(batch)
 	if err != nil {
@@ -544,7 +557,9 @@ func TestJetStreamSubscribe(t *testing.T) {
 			t.Fatal(err)
 		}
 	}
-	if info, _ := sub.ConsumerInfo(); info.AckFloor.Consumer != uint64(batch) {
+
+	// we expect AckFloor to be equal batch size + 1 from NextMsg alias test
+	if info, _ := sub.ConsumerInfo(); info.AckFloor.Consumer != uint64(batch+1) {
 		t.Fatalf("Expected ack floor to be %d, got %d", batch, info.AckFloor.Consumer)
 	}
 	waitForPending(t, 0)

From dad4664f20262854043f0da096ec5b1e9a2d6e8d Mon Sep 17 00:00:00 2001
From: Jarema <melgaer@gmail.com>
Date: Sat, 19 Jun 2021 21:44:23 +0200
Subject: [PATCH 3/3] Add more comments to tests

---
 test/js_test.go | 1 +
 1 file changed, 1 insertion(+)

diff --git a/test/js_test.go b/test/js_test.go
index 7335af3f9..5b88babe5 100644
--- a/test/js_test.go
+++ b/test/js_test.go
@@ -535,6 +535,7 @@ func TestJetStreamSubscribe(t *testing.T) {
 		t.Fatalf("Expected %d pending ack, and %d still waiting to be delivered, got %d and %d", 1, 1, info.NumAckPending, info.NumPending)
 	}
 
+	// do nat ack the message to not affect rest of the test by alias test
 	if err := nmsg.Nak(); err != nil {
 		t.Fatal(err)
 	}