Make sure to suppress dupes on JS deny all for system account

Signed-off-by: Derek Collison <derek@nats.io>

server/jetstream_cluster_test.go

@@ -6240,6 +6240,46 @@ func TestJetStreamClusterSuperClusterAndSingleLeafNodeWithSharedSystemAccount(t
 	}
 }
 
+func TestJetStreamClusterLeafNodeDenyNoDupe(t *testing.T) {
+	tmpl := strings.Replace(jsClusterAccountsTempl, "store_dir:", "domain: CORE, store_dir:", 1)
+	c := createJetStreamCluster(t, tmpl, "CORE", _EMPTY_, 3, 18033, true)
+	defer c.shutdown()
+
+	tmpl = strings.Replace(jsClusterTemplWithSingleLeafNode, "store_dir:", "domain: SPOKE, store_dir:", 1)
+	ln := c.createLeafNodeWithTemplate("LN-SPOKE", tmpl)
+	defer ln.Shutdown()
+
+	checkLeafNodeConnectedCount(t, ln, 2)
+
+	// Now disconnect our leafnode connections by restarting the server we are connected to..
+	for _, s := range c.servers {
+		if s.ClusterName() != c.name {
+			continue
+		}
+		if nln := s.NumLeafNodes(); nln > 0 {
+			s.Shutdown()
+			c.restartServer(s)
+		}
+	}
+	// Make sure we are back connected.
+	checkLeafNodeConnectedCount(t, ln, 2)
+
+	// Now grab leaf varz and make sure we have no dupe deny clauses.
+	vz, err := ln.Varz(nil)
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	// Grab the correct remote.
+	for _, remote := range vz.LeafNode.Remotes {
+		if remote.LocalAccount == ln.SystemAccount().Name {
+			if len(remote.Deny.Exports) > 3 { // denyAll := []string{jscAllSubj, raftAllSubj, jsAllAPI}
+				t.Fatalf("Dupe entries found: %+v", remote.Deny)
+			}
+			break
+		}
+	}
+}
+
 // Multiple JS domains.
 func TestJetStreamClusterSingleLeafNodeWithoutSharedSystemAccount(t *testing.T) {
 	c := createJetStreamCluster(t, jsClusterAccountsTempl, "HUB", _EMPTY_, 3, 14333, true)

server/leafnode.go

@@ -170,14 +170,35 @@ func (s *Server) addInJSDenyAll(r *leafNodeCfg) {
 	s.Noticef("Sharing system account but utilizing separate JetStream Domains")
 	s.Noticef("Adding deny of %+v for leafnode configuration that bridges system account", denyAll)
 
-	r.DenyExports = append(r.DenyExports, denyAll...)
-	r.DenyImports = append(r.DenyImports, denyAll...)
+	hasDeny := func(deny string, l []string) bool {
+		for _, le := range l {
+			if le == deny {
+				return true
+			}
+		}
+		return false
+	}
+
+	var exportAdded, importAdded bool
+	for _, deny := range denyAll {
+		if !hasDeny(deny, r.DenyExports) {
+			r.DenyExports = append(r.DenyExports, deny)
+			exportAdded = true
+		}
+		if !hasDeny(deny, r.DenyImports) {
+			r.DenyImports = append(r.DenyImports, deny)
+			importAdded = true
+		}
+	}
+	if !exportAdded && !importAdded {
+		return
+	}
 
 	perms := &Permissions{}
-	if len(r.DenyExports) > 0 {
+	if exportAdded {
 		perms.Publish = &SubjectPermission{Deny: r.DenyExports}
 	}
-	if len(r.DenyImports) > 0 {
+	if importAdded {
 		perms.Subscribe = &SubjectPermission{Deny: r.DenyImports}
 	}
 	r.perms = perms