mirror of https://github.com/grpc/grpc-java.git
c131d2dd14
We got a NullPointerException from ClientCallImpl#startDeadlineTimer
when a new Call is created after a Netty channel is terminated. Here
is a stacktrace:
INTERNAL: java.lang.NullPointerException
at io.grpc.internal.ClientCallImpl.startDeadlineTimer(ClientCallImpl.java:320)
at io.grpc.internal.ClientCallImpl.start(ClientCallImpl.java:253)
The following code snippet reproduces the bug:
```
ManagedChannel channel = NettyChannelBuilder.forAddress(host, port)
.usePlaintext(true)
.build();
channel.shutdown();
Thread.sleep(1000);
GreeterGrpc.GreeterBlockingStub stub =
GreeterGrpc.newBlockingStub(channel)
.withDeadlineAfter(10, TimeUnit.SECONDS);
stub.sayHello(HelloRequest.newBuilder().setName("world").build());
```
The issue was that ClientCallImpl is created from RealChannel#newCall
*after* ManagedChannelImpl#maybeTerminateChannel is called and
scheduledExecutor is set to null. In such a scenario,
deadlineCancellationExecutor is set to null.
I think there are several ways to fix this, but one way would be to
just avoid calling startDeadlineTimer() when
deadlineCancellationExecutor is null. DelayedClientTransport will
create a FailingClientStream with Status.UNAVAILABLE and we will get
```
Exception in thread "main" io.grpc.StatusRuntimeException:
UNAVAILABLE: Channel has shutdown (reported by delayed transport)
```
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