Fix bug of ignoring subchannels with CONNECTING state when aggregating the overall load balancing state.

Author: voidzcy

grpclb/src/main/java/io/grpc/grpclb/GrpclbState.java

@@ -776,7 +776,7 @@ private void maybeUpdatePicker() {
       case ROUND_ROBIN:
         pickList = new ArrayList<>(backendList.size());
         Status error = null;
-        boolean hasIdle = false;
+        boolean hasPending = false;
         for (BackendEntry entry : backendList) {
           Subchannel subchannel = entry.subchannel;
           Attributes attrs = subchannel.getAttributes();
@@ -785,12 +785,12 @@ private void maybeUpdatePicker() {
             pickList.add(entry);
           } else if (stateInfo.getState() == TRANSIENT_FAILURE) {
             error = stateInfo.getStatus();
-          } else if (stateInfo.getState() == IDLE) {
-            hasIdle = true;
+          } else {
+            hasPending = true;
           }
         }
         if (pickList.isEmpty()) {
-          if (error != null && !hasIdle) {
+          if (error != null && !hasPending) {
             pickList.add(new ErrorEntry(error));
             state = TRANSIENT_FAILURE;
           } else {

grpclb/src/test/java/io/grpc/grpclb/GrpclbLoadBalancerTest.java

@@ -1175,9 +1175,10 @@ public void roundRobinMode_subchannelStayTransientFailureUntilReady() {
     deliverSubchannelState(subchannel2, ConnectivityStateInfo.forNonError(CONNECTING));
     inOrder.verify(helper).updateBalancingState(eq(CONNECTING), any(SubchannelPicker.class));
 
-    // Switch subchannel1 to TRANSIENT_FAILURE, making the general state TRANSIENT_FAILURE too.
-    Status error = Status.UNAVAILABLE.withDescription("error1");
+    // Switch all subchannels to TRANSIENT_FAILURE, making the general state TRANSIENT_FAILURE too.
+    Status error = Status.UNAVAILABLE.withDescription("error");
     deliverSubchannelState(subchannel1, ConnectivityStateInfo.forTransientFailure(error));
+    deliverSubchannelState(subchannel2, ConnectivityStateInfo.forTransientFailure(error));
     inOrder.verify(helper).updateBalancingState(eq(TRANSIENT_FAILURE), pickerCaptor.capture());
     assertThat(((RoundRobinPicker) pickerCaptor.getValue()).pickList)
         .containsExactly(new ErrorEntry(error));