core: fix a bug in health check config propgation. (#6804)

The condition "effectiveServiceConfig != validServiceConfig" should
have been deleted in commit 2162ad0.

The condition was there before that commit because
NAME_RESOLVER_SERVICE_CONFIG was already in "attrs", thus it needed to
be re-added only if "effectiveServiceConfig" differs from the original
"validServiceConfig".

In contrast, ATTR_HEALTH_CHECKING_CONFIG is not in the original
"attrs" and always needs to be added.

core/src/main/java/io/grpc/internal/ManagedChannelImpl.java

@@ -1399,14 +1399,12 @@ public void run() {
           Attributes effectiveAttrs = resolutionResult.getAttributes();
           // Call LB only if it's not shutdown.  If LB is shutdown, lbHelper won't match.
           if (NameResolverListener.this.helper == ManagedChannelImpl.this.lbHelper) {
-            if (effectiveServiceConfig != validServiceConfig) {
-              Map<String, ?> healthCheckingConfig =
-                  effectiveServiceConfig.getHealthCheckingConfig();
-              if (healthCheckingConfig != null) {
-                effectiveAttrs = effectiveAttrs.toBuilder()
-                    .set(LoadBalancer.ATTR_HEALTH_CHECKING_CONFIG, healthCheckingConfig)
-                    .build();
-              }
+            Map<String, ?> healthCheckingConfig =
+                effectiveServiceConfig.getHealthCheckingConfig();
+            if (healthCheckingConfig != null) {
+              effectiveAttrs = effectiveAttrs.toBuilder()
+                  .set(LoadBalancer.ATTR_HEALTH_CHECKING_CONFIG, healthCheckingConfig)
+                  .build();
             }
 
             Status handleResult = helper.lb.tryHandleResolvedAddresses(

core/src/test/java/io/grpc/internal/ManagedChannelImplTest.java

@@ -3918,6 +3918,36 @@ public void notUseDefaultImmediatelyIfEnableLookUp() throws Exception {
             .build());
   }
 
+  @Test
+  public void healthCheckingConfigPropagated() throws Exception {
+    LoadBalancerRegistry.getDefaultRegistry().register(mockLoadBalancerProvider);
+    try {
+      FakeNameResolverFactory nameResolverFactory =
+          new FakeNameResolverFactory.Builder(expectedUri)
+              .setServers(Collections.singletonList(new EquivalentAddressGroup(socketAddress)))
+              .build();
+      channelBuilder.nameResolverFactory(nameResolverFactory);
+
+      Map<String, Object> rawServiceConfig =
+          parseConfig("{\"healthCheckConfig\": {\"serviceName\": \"service1\"}}");
+      ManagedChannelServiceConfig managedChannelServiceConfig =
+          createManagedChannelServiceConfig(rawServiceConfig, null);
+      nameResolverFactory.nextConfigOrError.set(
+          ConfigOrError.fromConfig(managedChannelServiceConfig));
+
+      createChannel();
+
+      ArgumentCaptor<ResolvedAddresses> resultCaptor =
+          ArgumentCaptor.forClass(ResolvedAddresses.class);
+      verify(mockLoadBalancer).handleResolvedAddresses(resultCaptor.capture());
+      assertThat(resultCaptor.getValue().getAttributes()
+          .get(LoadBalancer.ATTR_HEALTH_CHECKING_CONFIG))
+          .containsExactly("serviceName", "service1");
+    } finally {
+      LoadBalancerRegistry.getDefaultRegistry().deregister(mockLoadBalancerProvider);
+    }
+  }
+
   private static final class ChannelBuilder
       extends AbstractManagedChannelImplBuilder<ChannelBuilder> {