fix empty resource subscription

lujiajing1126 · lujiajing1126 · commit 037cdef81b73 · 2024-06-05T16:46:56.000+08:00
diff --git a/xds/src/main/java/io/grpc/xds/client/ControlPlaneClient.java b/xds/src/main/java/io/grpc/xds/client/ControlPlaneClient.java
@@ -152,9 +152,7 @@ void adjustResourceSubscription(XdsResourceType<?> resourceType) {
       startRpcStream();
     }
     Collection<String> resources = resourceStore.getSubscribedResources(serverInfo, resourceType);
-    if (resources != null) {
-      adsStream.sendDiscoveryRequest(resourceType, resources);
-    }
+    adsStream.sendDiscoveryRequest(resourceType, resources == null ? Collections.emptySet() : resources);
   }
 
   /**
diff --git a/xds/src/test/java/io/grpc/xds/GrpcXdsClientImplTestBase.java b/xds/src/test/java/io/grpc/xds/GrpcXdsClientImplTestBase.java
@@ -2783,13 +2783,15 @@ public void edsAllowRespondAfterUnsubscription() {
     // 1) the EDS unsubscription caused by CDS PUSH e1 (client-side) and,
     // 2) the immediate EDS PUSH from XdsServer (server-side) after CDS PUSH e1 (event e2).
     xdsClient.cancelXdsResourceWatch(XdsEndpointResource.getInstance(), "A.1", edsResourceWatcher);
+    // FIX(1): allow to send empty subscription
+    call.verifyRequest(EDS, Collections.emptyList(), VERSION_1, "0000", NODE);
     verifySubscribedResourcesMetadataSizes(0, 0, 0, 0);
     // An EDS PUSH after CDS PUSH e1.
     List<Message> endpointsV2 = ImmutableList.of(lbEndpointHealthy);
     ImmutableMap<String, Any> resourcesV2 = ImmutableMap.of(
             "A.1", Any.pack(mf.buildClusterLoadAssignment("A.1", endpointsV2, dropOverloads)));
     call.sendResponse(EDS, resourcesV2.values().asList(), VERSION_2, "0001");
-    // This will send an empty resource list to the XdsServer
+    // FIX(2): allow to update resource version even if the subscription resource is empty
     call.verifyRequest(EDS, Collections.emptyList(), VERSION_2, "0001", NODE);
     verifyNoMoreInteractions(edsResourceWatcher);
   }

Original file line number	Diff line number	Diff line change
`@@ -152,9 +152,7 @@ void adjustResourceSubscription(XdsResourceType<?> resourceType) {`
`152`	`152`	`startRpcStream();`
`153`	`153`	`}`
`154`	`154`	`Collection<String> resources = resourceStore.getSubscribedResources(serverInfo, resourceType);`
`155`		`- if (resources != null) {`
`156`		`- adsStream.sendDiscoveryRequest(resourceType, resources);`
`157`		`- }`
	`155`	`+ adsStream.sendDiscoveryRequest(resourceType, resources == null ? Collections.emptySet() : resources);`
`158`	`156`	`}`
`159`	`157`
`160`	`158`	`/**`