From faa6dc85eb01cc068b605572737046a52ea01c74 Mon Sep 17 00:00:00 2001
From: Derek Collison <derek@nats.io>
Date: Sat, 20 Mar 2021 11:16:40 -0700
Subject: [PATCH] Fix for flapping test

Signed-off-by: Derek Collison <derek@nats.io>
---
 server/jetstream_cluster.go      | 17 ++++++++++++++++-
 server/jetstream_cluster_test.go |  8 ++++----
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/server/jetstream_cluster.go b/server/jetstream_cluster.go
index c912ed5f..671ccda6 100644
--- a/server/jetstream_cluster.go
+++ b/server/jetstream_cluster.go
@@ -3160,7 +3160,22 @@ func (s *Server) jsClusteredStreamRequest(ci *ClientInfo, acc *Account, subject,
 	cfg := &ccfg
 
 	js.mu.RLock()
-	numStreams := len(cc.streams[acc.Name])
+	asa := cc.streams[acc.Name]
+	numStreams := len(asa)
+
+	// Check for subject collisions here.
+	for _, sa := range asa {
+		for _, subj := range sa.Config.Subjects {
+			for _, tsubj := range cfg.Subjects {
+				if SubjectsCollide(tsubj, subj) {
+					js.mu.RUnlock()
+					resp.Error = jsError(fmt.Errorf("subjects overlap with an existing stream"))
+					s.sendAPIErrResponse(ci, acc, subject, reply, string(rmsg), s.jsonResponse(&resp))
+					return
+				}
+			}
+		}
+	}
 	js.mu.RUnlock()
 
 	// Check for stream limits here before proposing. These need to be tracked from meta layer, not jsa.
diff --git a/server/jetstream_cluster_test.go b/server/jetstream_cluster_test.go
index fa45e2ff..13c435a7 100644
--- a/server/jetstream_cluster_test.go
+++ b/server/jetstream_cluster_test.go
@@ -1013,7 +1013,7 @@ func TestJetStreamClusterStreamPublishWithActiveConsumers(t *testing.T) {
 }
 
 func TestJetStreamClusterStreamOverlapSubjects(t *testing.T) {
-	c := createJetStreamClusterExplicit(t, "R32", 2)
+	c := createJetStreamClusterExplicit(t, "R3", 3)
 	defer c.shutdown()
 
 	// Client based API
@@ -1021,12 +1021,12 @@ func TestJetStreamClusterStreamOverlapSubjects(t *testing.T) {
 	nc, js := jsClientConnect(t, s)
 	defer nc.Close()
 
-	if _, err := js.AddStream(&nats.StreamConfig{Name: "TEST", Subjects: []string{"foo"}, Replicas: 2}); err != nil {
+	if _, err := js.AddStream(&nats.StreamConfig{Name: "TEST", Subjects: []string{"foo"}}); err != nil {
 		t.Fatalf("Unexpected error: %v", err)
 	}
 
-	if _, err := js.AddStream(&nats.StreamConfig{Name: "TEST2", Subjects: []string{"foo"}, Replicas: 2}); err == nil || err == nats.ErrTimeout {
-		t.Fatalf("Expected error but got none or timeout")
+	if _, err := js.AddStream(&nats.StreamConfig{Name: "TEST2", Subjects: []string{"foo"}}); err == nil || err == nats.ErrTimeout {
+		t.Fatalf("Expected error but got none or timeout: %v", err)
 	}
 
 	// Now grab list of streams and make sure the second is not there.