Revert "xds: xdsClient caches transient error for new watchers (v1.75.x backport) (grpc#12291)"

This reverts commit 14fd8ef.

Author: kannanjgithub

xds/src/main/java/io/grpc/xds/client/XdsClientImpl.java

@@ -676,8 +676,6 @@ private final class ResourceSubscriber<T extends ResourceUpdate> {
     private ResourceMetadata metadata;
     @Nullable
     private String errorDescription;
-    @Nullable
-    private Status lastError;
 
     ResourceSubscriber(XdsResourceType<T> type, String resource) {
       syncContext.throwIfNotInThisSynchronizationContext();
@@ -714,16 +712,11 @@ void addWatcher(ResourceWatcher<T> watcher, Executor watcherExecutor) {
       watchers.put(watcher, watcherExecutor);
       T savedData = data;
       boolean savedAbsent = absent;
-      Status savedError = lastError;
       watcherExecutor.execute(() -> {
         if (errorDescription != null) {
           watcher.onError(Status.INVALID_ARGUMENT.withDescription(errorDescription));
           return;
         }
-        if (savedError != null) {
-          watcher.onError(savedError);
-          return;
-        }
         if (savedData != null) {
           notifyWatcher(watcher, savedData);
         } else if (savedAbsent) {
@@ -815,7 +808,6 @@ void onData(ParsedResource<T> parsedResource, String version, long updateTime,
       this.metadata = ResourceMetadata
           .newResourceMetadataAcked(parsedResource.getRawResource(), version, updateTime);
       absent = false;
-      lastError = null;
       if (resourceDeletionIgnored) {
         logger.log(XdsLogLevel.FORCE_INFO, "xds server {0}: server returned new version "
                 + "of resource for which we previously ignored a deletion: type {1} name {2}",
@@ -865,7 +857,6 @@ void onAbsent(@Nullable ProcessingTracker processingTracker, ServerInfo serverIn
       if (!absent) {
         data = null;
         absent = true;
-        lastError = null;
         metadata = serverInfo.resourceTimerIsTransientError()
             ? ResourceMetadata.newResourceMetadataTimeout()
             : ResourceMetadata.newResourceMetadataDoesNotExist();
@@ -903,7 +894,6 @@ void onError(Status error, @Nullable ProcessingTracker tracker) {
       Status errorAugmented = Status.fromCode(error.getCode())
           .withDescription(description + "nodeID: " + bootstrapInfo.node().getId())
           .withCause(error.getCause());
-      this.lastError = errorAugmented;
 
       for (ResourceWatcher<T> watcher : watchers.keySet()) {
         if (tracker != null) {

xds/src/test/java/io/grpc/xds/GrpcXdsClientImplTestBase.java

@@ -285,8 +285,6 @@ public long currentTimeNanos() {
   @Mock
   private ResourceWatcher<LdsUpdate> ldsResourceWatcher;
   @Mock
-  private ResourceWatcher<LdsUpdate> ldsResourceWatcher2;
-  @Mock
   private ResourceWatcher<RdsUpdate> rdsResourceWatcher;
   @Mock
   private ResourceWatcher<CdsUpdate> cdsResourceWatcher;
@@ -696,24 +694,6 @@ public void ldsResourceUpdated_withXdstpResourceName_withUnknownAuthority() {
     assertThat(resourceDiscoveryCalls.poll()).isNull();
   }
 
-  @Test
-  public void ldsResource_onError_cachedForNewWatcher() {
-    xdsClient.watchXdsResource(XdsListenerResource.getInstance(), LDS_RESOURCE,
-        ldsResourceWatcher);
-    DiscoveryRpcCall call = resourceDiscoveryCalls.poll();
-    call.sendCompleted();
-    verify(ldsResourceWatcher).onError(errorCaptor.capture());
-    Status initialError = errorCaptor.getValue();
-    xdsClient.watchXdsResource(XdsListenerResource.getInstance(), LDS_RESOURCE,
-        ldsResourceWatcher2);
-    ArgumentCaptor<Status> secondErrorCaptor = ArgumentCaptor.forClass(Status.class);
-    verify(ldsResourceWatcher2).onError(secondErrorCaptor.capture());
-    Status cachedError = secondErrorCaptor.getValue();
-
-    assertThat(cachedError).isEqualTo(initialError);
-    assertThat(resourceDiscoveryCalls.poll()).isNull();
-  }
-
   @Test
   public void ldsResponseErrorHandling_allResourcesFailedUnpack() {
     DiscoveryRpcCall call = startResourceWatcher(XdsListenerResource.getInstance(), LDS_RESOURCE,