#20432

Committed 01 Sep 2026 01:58PM UTC coverage: 89.218% (+0.008%) from 89.21%

Build # #20432

Build Type

push

github

Committed by

web-flow

Commit Message

fix(pick_first): ignore state updates from shut down or replaced subchannels (#12968)

In legacy PickFirstLoadBalancer, when handleNameResolutionError() or
shutdown() is called, subchannel.shutdown() is invoked. Because
ManagedChannelImpl delays subchannel shutdown by 5 seconds
(SUBCHANNEL_SHUTDOWN_DELAY_SECONDS), the old subchannel may complete a
connection attempt during this window and fire READY state updates.
Without a check verifying if the calling subchannel is still the current
active subchannel, PickFirstLoadBalancer publishes a READY picker for
the obsolete subchannel right before its 5-second delayed shutdown task
fires and kills the transport. This leaves the channel permanently stuck
in READY with a dead subchannel picker.

Partially addresses #12958

Coverage Stats

38642 of 43312 relevant lines covered (89.22%)

0.89 hits per line

Source File
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87.88

/../netty/src/main/java/io/grpc/netty/ClientTransportLifecycleManager.java

/*
 * Copyright 2016 The gRPC Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.grpc.netty;

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import io.grpc.Attributes;
import io.grpc.Status;
import io.grpc.internal.DisconnectError;
import io.grpc.internal.ManagedClientTransport;

/** Maintainer of transport lifecycle status. */
final class ClientTransportLifecycleManager {
  private final ManagedClientTransport.Listener listener;
  private boolean transportReady;
  private boolean transportShutdown;
  private boolean transportInUse;
  /** null iff !transportShutdown. */
  private Status shutdownStatus;
  /** null iff !transportShutdown. */
  private boolean transportTerminated;

  public ClientTransportLifecycleManager(ManagedClientTransport.Listener listener) {
    this.listener = listener;
  }

  public Attributes filterAttributes(Attributes attributes) {
    if (transportReady || transportShutdown) {
      return attributes;
    }
    return listener.filterTransport(attributes);
  }

  public void notifyReady() {
    if (transportReady || transportShutdown) {
      return;
    }
    transportReady = true;
    listener.transportReady();
  }

  /**
   * Marks transport as shutdown, but does not set the error status. This must eventually be
   * followed by a call to notifyShutdown.
   */
  public void notifyGracefulShutdown(Status s, DisconnectError disconnectError) {
    if (transportShutdown) {
      return;
    }
    transportShutdown = true;
    listener.transportShutdown(s, disconnectError);
  }

  /** Returns {@code true} if was the first shutdown. */
  @CanIgnoreReturnValue
  public boolean notifyShutdown(Status s, DisconnectError disconnectError) {
    notifyGracefulShutdown(s, disconnectError);
    if (shutdownStatus != null) {
      return false;
    }
    shutdownStatus = s;
    return true;
  }

  public void notifyInUse(boolean inUse) {
    if (inUse == transportInUse) {
      return;
    }
    transportInUse = inUse;
    listener.transportInUse(inUse);
  }

  public void notifyTerminated(Status s, DisconnectError disconnectError) {
    if (transportTerminated) {
      return;
    }
    transportTerminated = true;
    notifyShutdown(s, disconnectError);
    listener.transportTerminated();
  }

  public Status getShutdownStatus() {
    return shutdownStatus;
  }

}

1	/*
2	* Copyright 2016 The gRPC Authors
3	*
4	* Licensed under the Apache License, Version 2.0 (the "License");
5	* you may not use this file except in compliance with the License.
6	* You may obtain a copy of the License at
7	*
8	* http://www.apache.org/licenses/LICENSE-2.0
9	*
10	* Unless required by applicable law or agreed to in writing, software
11	* distributed under the License is distributed on an "AS IS" BASIS,
12	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13	* See the License for the specific language governing permissions and
14	* limitations under the License.
15	*/
16
17	package io.grpc.netty;
18
19	import com.google.errorprone.annotations.CanIgnoreReturnValue;
20	import io.grpc.Attributes;
21	import io.grpc.Status;
22	import io.grpc.internal.DisconnectError;
23	import io.grpc.internal.ManagedClientTransport;
24
25	/** Maintainer of transport lifecycle status. */
26	final class ClientTransportLifecycleManager {
27	private final ManagedClientTransport.Listener listener;
28	private boolean transportReady;
29	private boolean transportShutdown;
30	private boolean transportInUse;
31	/** null iff !transportShutdown. */
32	private Status shutdownStatus;
33	/** null iff !transportShutdown. */
34	private boolean transportTerminated;
35
36	public ClientTransportLifecycleManager(ManagedClientTransport.Listener listener) {	1 ✔
37	this.listener = listener;	1 ✔
38	}	1 ✔
39
40	public Attributes filterAttributes(Attributes attributes) {
41	if (transportReady \|\| transportShutdown) {	1 ✔
42	return attributes;	×
43	}
44	return listener.filterTransport(attributes);	1 ✔
45	}
46
47	public void notifyReady() {
48	if (transportReady \|\| transportShutdown) {	1 ✔
49	return;	×
50	}
51	transportReady = true;	1 ✔
52	listener.transportReady();	1 ✔
53	}	1 ✔
54
55	/**
56	* Marks transport as shutdown, but does not set the error status. This must eventually be
57	* followed by a call to notifyShutdown.
58	*/
59	public void notifyGracefulShutdown(Status s, DisconnectError disconnectError) {
60	if (transportShutdown) {	1 ✔
61	return;	1 ✔
62	}
63	transportShutdown = true;	1 ✔
64	listener.transportShutdown(s, disconnectError);	1 ✔
65	}	1 ✔
66
67	/** Returns {@code true} if was the first shutdown. */
68	@CanIgnoreReturnValue
69	public boolean notifyShutdown(Status s, DisconnectError disconnectError) {
70	notifyGracefulShutdown(s, disconnectError);	1 ✔
71	if (shutdownStatus != null) {	1 ✔
72	return false;	1 ✔
73	}
74	shutdownStatus = s;	1 ✔
75	return true;	1 ✔
76	}
77
78	public void notifyInUse(boolean inUse) {
79	if (inUse == transportInUse) {	1 ✔
80	return;	×
81	}
82	transportInUse = inUse;	1 ✔
83	listener.transportInUse(inUse);	1 ✔
84	}	1 ✔
85
86	public void notifyTerminated(Status s, DisconnectError disconnectError) {
87	if (transportTerminated) {	1 ✔
88	return;	×
89	}
90	transportTerminated = true;	1 ✔
91	notifyShutdown(s, disconnectError);	1 ✔
92	listener.transportTerminated();	1 ✔
93	}	1 ✔
94
95	public Status getShutdownStatus() {
96	return shutdownStatus;	1 ✔
97	}
98
99	}

grpc / grpc-java / #20432

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