[FIXED] Setting deliver policy in Fetch() for OrderedConsumer (#1693)

Signed-off-by: Piotr Piotrowski <piotr@synadia.com>

jetstream/ordered.go

@@ -583,7 +583,8 @@ func (c *orderedConsumer) getConsumerConfig() *ConsumerConfig {
 		cfg.InactiveThreshold = c.cfg.InactiveThreshold
 	}
 
-	if c.serial != 1 {
+	// if the cursor is not yet set, use the provided deliver policy
+	if c.cursor.streamSeq != 0 {
 		return cfg
 	}
 

jetstream/test/ordered_test.go

@@ -1119,6 +1119,71 @@ func TestOrderedConsumerFetch(t *testing.T) {
 		}
 	})
 
+	t.Run("with custom deliver policy", func(t *testing.T) {
+		srv := RunBasicJetStreamServer()
+		defer shutdownJSServerAndRemoveStorage(t, srv)
+		nc, err := nats.Connect(srv.ClientURL())
+		if err != nil {
+			t.Fatalf("Unexpected error: %v", err)
+		}
+
+		js, err := jetstream.New(nc)
+		if err != nil {
+			t.Fatalf("Unexpected error: %v", err)
+		}
+		defer nc.Close()
+
+		ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
+		defer cancel()
+		s, err := js.CreateStream(ctx, jetstream.StreamConfig{Name: "foo", Subjects: []string{"FOO.*"}})
+		if err != nil {
+			t.Fatalf("Unexpected error: %v", err)
+		}
+		msgs := make([]jetstream.Msg, 0)
+
+		for i := 0; i < 5; i++ {
+			if _, err := js.Publish(context.Background(), "FOO.A", []byte("msg")); err != nil {
+				t.Fatalf("Unexpected error during publish: %s", err)
+			}
+		}
+		for i := 0; i < 5; i++ {
+			if _, err := js.Publish(context.Background(), "FOO.B", []byte("msg")); err != nil {
+				t.Fatalf("Unexpected error during publish: %s", err)
+			}
+		}
+
+		c, err := s.OrderedConsumer(ctx, jetstream.OrderedConsumerConfig{
+			DeliverPolicy: jetstream.DeliverLastPerSubjectPolicy,
+		})
+		if err != nil {
+			t.Fatalf("Unexpected error: %v", err)
+		}
+
+		res, err := c.Fetch(int(c.CachedInfo().NumPending), jetstream.FetchMaxWait(1*time.Second))
+		if err != nil {
+			t.Fatalf("Unexpected error: %s", err)
+		}
+
+		for msg := range res.Messages() {
+			msgs = append(msgs, msg)
+		}
+
+		if res.Error() != nil {
+			t.Fatalf("Unexpected error: %s", err)
+		}
+
+		if len(msgs) != 2 {
+			t.Fatalf("Expected %d messages; got: %d", 2, len(msgs))
+		}
+		expectedSubjects := []string{"FOO.A", "FOO.B"}
+
+		for i := range msgs {
+			if msgs[i].Subject() != expectedSubjects[i] {
+				t.Fatalf("Expected subject: %s; got: %s", expectedSubjects[i], msgs[i].Subject())
+			}
+		}
+	})
+
 	t.Run("consumer used as consume", func(t *testing.T) {
 		srv := RunBasicJetStreamServer()
 		defer shutdownJSServerAndRemoveStorage(t, srv)