From 877b1a198fe9fc01315727105a0331f09490c78d Mon Sep 17 00:00:00 2001
From: Eric Gribkoff <ericgribkoff@google.com>
Date: Mon, 23 Jul 2018 09:45:06 -0700
Subject: [PATCH] core: enterIdleMode() exits idle if still in use (#4630)

---
 .../io/grpc/internal/ManagedChannelImpl.java  |  3 ++
 .../grpc/internal/ManagedChannelImplTest.java | 44 +++++++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/core/src/main/java/io/grpc/internal/ManagedChannelImpl.java b/core/src/main/java/io/grpc/internal/ManagedChannelImpl.java
index 7b6fc9e015..1ee538a836 100644
--- a/core/src/main/java/io/grpc/internal/ManagedChannelImpl.java
+++ b/core/src/main/java/io/grpc/internal/ManagedChannelImpl.java
@@ -395,6 +395,9 @@ final class ManagedChannelImpl extends ManagedChannel implements Instrumented<Ch
               .build());
     }
     channelStateManager.gotoState(IDLE);
+    if (inUseStateAggregator.isInUse()) {
+      exitIdleMode();
+    }
   }
 
   // Must be run from channelExecutor
diff --git a/core/src/test/java/io/grpc/internal/ManagedChannelImplTest.java b/core/src/test/java/io/grpc/internal/ManagedChannelImplTest.java
index 9203ecea46..69eb1a6931 100644
--- a/core/src/test/java/io/grpc/internal/ManagedChannelImplTest.java
+++ b/core/src/test/java/io/grpc/internal/ManagedChannelImplTest.java
@@ -1935,6 +1935,50 @@ public class ManagedChannelImplTest {
     assertEquals(IDLE, channel.getState(false));
   }
 
+  @Test
+  public void enterIdle_exitsIdleIfDelayedStreamPending() {
+    FakeNameResolverFactory nameResolverFactory =
+        new FakeNameResolverFactory.Builder(expectedUri)
+            .setServers(Collections.singletonList(new EquivalentAddressGroup(socketAddress)))
+            .build();
+    channelBuilder.nameResolverFactory(nameResolverFactory);
+    createChannel();
+
+    // Start a call that will be buffered in delayedTransport
+    ClientCall<String, Integer> call = channel.newCall(method, CallOptions.DEFAULT);
+    call.start(mockCallListener, new Metadata());
+
+    // enterIdle() will shut down the name resolver and lb policy used to get a pick for the delayed
+    // call
+    channel.enterIdle();
+    assertEquals(IDLE, channel.getState(false));
+
+    // enterIdle() will restart the delayed call by exiting idle. This creates a new helper.
+    ArgumentCaptor<Helper> helperCaptor = ArgumentCaptor.forClass(Helper.class);
+    verify(mockLoadBalancerFactory, times(2)).newLoadBalancer(helperCaptor.capture());
+    Helper helper2 = helperCaptor.getValue();
+
+    // Establish a connection
+    Subchannel subchannel = helper2.createSubchannel(addressGroup, Attributes.EMPTY);
+    subchannel.requestConnection();
+    ClientStream mockStream = mock(ClientStream.class);
+    MockClientTransportInfo transportInfo = transports.poll();
+    ConnectionClientTransport mockTransport = transportInfo.transport;
+    ManagedClientTransport.Listener transportListener = transportInfo.listener;
+    when(mockTransport.newStream(same(method), any(Metadata.class), any(CallOptions.class)))
+        .thenReturn(mockStream);
+    transportListener.transportReady();
+    when(mockPicker.pickSubchannel(any(PickSubchannelArgs.class)))
+        .thenReturn(PickResult.withSubchannel(subchannel));
+    helper2.updateBalancingState(READY, mockPicker);
+    assertEquals(READY, channel.getState(false));
+
+    // Verify the original call was drained
+    executor.runDueTasks();
+    verify(mockTransport).newStream(same(method), any(Metadata.class), any(CallOptions.class));
+    verify(mockStream).start(any(ClientStreamListener.class));
+  }
+
   @Test
   public void updateBalancingStateDoesUpdatePicker() {
     ClientStream mockStream = mock(ClientStream.class);