xds:fix cdsLoadBalancer2 childLb shutdown (grpc#7976)

Add missing childLb shutdown at cdsLoadBalancer state. The bug would cause xds client channels to be shutdown prematurely before childLb, e.g. ClusterResolverLoadBalancer. The resources referencing the client channel would be causing unexpected exceptions triggering channel panic, e.g. when EdsClusterState internal of ClusterResolverLoadBalancer can still be updated upon xds responses.
ejona86 · Mar 17, 2021 · e3dd9ad · e3dd9ad
1 parent c530094
commit e3dd9ad
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diff --git a/xds/src/main/java/io/grpc/xds/CdsLoadBalancer2.java b/xds/src/main/java/io/grpc/xds/CdsLoadBalancer2.java
@@ -133,6 +133,9 @@ private void start() {
 
     private void shutdown() {
       root.shutdown();
+      if (childLb != null) {
+        childLb.shutdown();
+      }
     }
 
     private void handleClusterDiscovered() {

diff --git a/xds/src/test/java/io/grpc/xds/CdsLoadBalancer2Test.java b/xds/src/test/java/io/grpc/xds/CdsLoadBalancer2Test.java
@@ -143,6 +143,7 @@ public void tearDown() {
     loadBalancer.shutdown();
     assertThat(xdsClient.watchers).isEmpty();
     assertThat(xdsClientRefs).isEqualTo(0);
+    assertThat(childBalancers).isEmpty();
   }
 
   @Test