From 00ae0c57cc0a418f5208906d4f68c4b682dc662c Mon Sep 17 00:00:00 2001
From: Aliaksandr Mianzhynski <amenzhinsky@gmail.com>
Date: Thu, 17 Jun 2021 20:23:18 +0300
Subject: [PATCH] xds: require router filter when filters are empty (#4553)

---
 xds/internal/resolver/serviceconfig.go     | 3 ---
 xds/internal/resolver/xds_resolver_test.go | 5 +++++
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/xds/internal/resolver/serviceconfig.go b/xds/internal/resolver/serviceconfig.go
index 9eaff52db..bf1c53fc9 100644
--- a/xds/internal/resolver/serviceconfig.go
+++ b/xds/internal/resolver/serviceconfig.go
@@ -255,9 +255,6 @@ func (cs *configSelector) generateHash(rpcInfo iresolver.RPCInfo, hashPolicies [
 }
 
 func (cs *configSelector) newInterceptor(rt *route, cluster *routeCluster) (iresolver.ClientInterceptor, error) {
-	if len(cs.httpFilterConfig) == 0 {
-		return nil, nil
-	}
 	interceptors := make([]iresolver.ClientInterceptor, 0, len(cs.httpFilterConfig))
 	for _, filter := range cs.httpFilterConfig {
 		if router.IsRouterFilter(filter.Filter) {
diff --git a/xds/internal/resolver/xds_resolver_test.go b/xds/internal/resolver/xds_resolver_test.go
index 9bce8ffe8..462298235 100644
--- a/xds/internal/resolver/xds_resolver_test.go
+++ b/xds/internal/resolver/xds_resolver_test.go
@@ -1197,6 +1197,11 @@ func (s) TestXDSResolverHTTPFilters(t *testing.T) {
 		selectErr    string
 		newStreamErr string
 	}{
+		{
+			name:       "empty filters",
+			ldsFilters: []xdsclient.HTTPFilter{},
+			selectErr:  "no router filter present",
+		},
 		{
 			name: "no router filter",
 			ldsFilters: []xdsclient.HTTPFilter{