Respond with `basic.cancel-ok` to the servers that support it by michaelklishin · Pull Request #2113 · rabbitmq/rabbitmq-java-client

michaelklishin · 2026-10-06T01:29:04Z

If the server advertises basic.cancel-ok response support.

The background on this is this: starting with 4.3.0, a delivery acknowledgement timeout does not result in the channel being closed but rather a
basic.cancel sent to the client.

Between about 2011 and 2026, clients never had
the need to respond to such basic.cancel because it was originally a client-sent method
and with consumer cancel notifications (an AMQP 0-9-1 extension), the client-sent confirmation was never required or expected.

Unfortunately, RabbitMQ versions between 4.3.0
and 4.3.6 only clean up the consumer after
a basic.cancel-ok arrives but older versions
cannot handle basic.cancel-ok, hence the new
capability and the conditional confirmation.

The Server Part of the Changes

See rabbitmq/rabbitmq-server#17734 for what's being
changed on the server to restore compatibility with older clients.

If the server advertises `basic.cancel-ok` response support. The background on this is this: starting with `4.3.0`, a delivery acknowledgement timeout does not result in the channel being closed but rather a `basic.cancel` sent to the client. Between about 2011 and 2026, clients never had the need to respond to such `basic.cancel` because it was originally a client method. Unfortunately, RabbitMQ versions between `4.3.0` and `4.3.6` only clean up the consumer after a `basic.cancel-ok` arrives but older versions cannot handle `basic.cancel-ok`, hence the new capability and the conditional confirmation.

…ered client callback

Copilot

Copilot review overview

🟡 Changes recommended

The new test helper contains a race that can discard the simulated response and hang the test suite.

Review effort: Balanced
Findings: 1

Open (1)

Drive mocked reply from Basic.Consume write to prevent race and hang · New

What changed in this PR

Adds capability-gated basic.cancel-ok responses for server-initiated consumer cancellation.

Changes:

Introduces server capability detection
Sends conditional cancellation acknowledgements
Adds capability and channel behavior tests

File	Description
`ServerCapability.java`	Defines advertised server capabilities
`AMQConnection.java`	Detects server capability support
`ChannelN.java`	Sends conditional `basic.cancel-ok` responses
`AMQConnectionCapabilitiesTest.java`	Tests capability detection
`ChannelNTest.java`	Tests cancellation response behavior

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

+        new Thread(() -> {
+            try {
+                Thread.sleep(15);
+                channel.handleCompleteInboundCommand(
+                    new AMQCommand(new AMQImpl.Basic.ConsumeOk(consumerTag)));
+            } catch (Exception e) {
+                throw new RuntimeException(e);
+            }
+        }).start();


michaelklishin · 2026-10-06T14:37:47Z

Thank you, @acogoluegnes.

michaelklishin · 2026-10-06T14:38:01Z

@Mergifyio backport v5.x

mergify · 2026-10-06T14:38:06Z

backport v5.x

✅ Backports have been created

Details

#2114 Respond with `basic.cancel-ok` to the servers that support it (backport #2113) has been created for branch v5.x but encountered conflicts

Cherry-pick of 1c9a5c0 has failed:

On branch mergify/bp/v5.x/pr-2113
Your branch is up to date with 'origin/v5.x'.

You are currently cherry-picking commit 1c9a5c0.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	new file:   src/main/java/com/rabbitmq/client/ServerCapability.java
	modified:   src/main/java/com/rabbitmq/client/impl/AMQConnection.java
	modified:   src/main/java/com/rabbitmq/client/impl/ChannelN.java
	new file:   src/test/java/com/rabbitmq/client/impl/AMQConnectionCapabilitiesTest.java

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   src/test/java/com/rabbitmq/client/test/ChannelNTest.java

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

Respond with `basic.cancel-ok` to the servers that support it (backport #2113)

Starting with RabbitMQ 4.3.0, a delivery acknowledgement timeout cancels the consumer with a broker-sent `Basic.Cancel` instead of closing the channel, and the broker expects a `Basic.CancelOk` reply. Brokers older than 4.3.0 do not accept the reply, so only reply to brokers that advertise the `accept_consumer_cancel_ok` capability. For more details, see rabbitmq/rabbitmq-server#17734 and rabbitmq/rabbitmq-java-client#2113.

Starting with RabbitMQ 4.3.0, a delivery acknowledgement timeout cancels the consumer with a broker-sent `basic.cancel` instead of closing the channel, and the broker expects a `basic.cancel-ok` reply. Brokers older than 4.3.0 do not accept the reply, so only reply to brokers that advertise the `accept_consumer_cancel_ok` capability. For more details, see rabbitmq/rabbitmq-server#17734 and rabbitmq/rabbitmq-java-client#2113.

Starting with RabbitMQ 4.3.0, a delivery acknowledgement timeout cancels the consumer with a broker-sent `Basic.Cancel` instead of closing the channel, and the broker expects a `Basic.CancelOk` reply. Brokers older than 4.3.0 do not accept the reply, so only reply to brokers that advertise the `accept_consumer_cancel_ok` capability. For more details, see rabbitmq/rabbitmq-server#17734 and rabbitmq/rabbitmq-java-client#2113.

Starting with RabbitMQ 4.3.0, a delivery acknowledgement timeout cancels the consumer with a broker-sent `basic.cancel` instead of closing the channel, and the broker expects a `basic.cancel-ok` reply. Brokers older than 4.3.0 do not accept the reply, so only reply to brokers that advertise the `accept_consumer_cancel_ok` capability. For more details, see rabbitmq/rabbitmq-server#17734 and rabbitmq/rabbitmq-java-client#2113.

michaelklishin added this to the 6.0.0 milestone Oct 6, 2026

michaelklishin force-pushed the mk-basic-cancel-ok-server-capability branch from a50d7af to 1c9a5c0 Compare October 6, 2026 01:30

JDK 8 compat

5049c5c

michaelklishin mentioned this pull request Oct 6, 2026

Consumer delivery timeout notifications: restore compatibility with older clients rabbitmq/rabbitmq-server#17734

Merged

Send basic.cancel-ok to capable servers even when there's no regist…

7004178

…ered client callback

acogoluegnes requested a balanced review from Copilot October 6, 2026 06:20

Copilot started reviewing on behalf of acogoluegnes October 6, 2026 06:21

View session

Copilot AI reviewed Oct 6, 2026

View reviewed changes

acogoluegnes added 2 commits October 6, 2026 12:04

test: fix race condition

07f413f

refactor: make enum and methods package-protected

8e09783

Zerpet mentioned this pull request Oct 6, 2026

Add support for basic cancel ok response rabbitmq/amqp091-go#405

Merged

acogoluegnes approved these changes Oct 6, 2026

View reviewed changes

michaelklishin merged commit 68419a1 into main Oct 6, 2026
7 checks passed

michaelklishin deleted the mk-basic-cancel-ok-server-capability branch October 6, 2026 14:37

mergify Bot mentioned this pull request Oct 6, 2026

Consumer delivery timeout notifications: restore compatibility with older clients (backport #17734) rabbitmq/rabbitmq-server#17740

Merged

This was referenced Oct 6, 2026

Respond with basic.cancel-ok to the servers that support it (backport #2113) #2114

Merged

Consumer delivery timeout notifications: restore compatibility with older clients (backport #17734) (backport #17740) rabbitmq/rabbitmq-server#17741

Merged

michaelklishin added a commit that referenced this pull request Oct 6, 2026

Merge pull request #2114 from rabbitmq/mergify/bp/v5.x/pr-2113

b4841d1

Respond with `basic.cancel-ok` to the servers that support it (backport #2113)

This was referenced Oct 7, 2026

Reply with Basic.CancelOk to brokers that accept it pika/pika#1722

Merged

Reply with basic.cancel-ok to brokers that accept it rabbitmq/rabbitmq-dotnet-client#2052

Merged

Navigation Menu

Repository navigation

Respond with `basic.cancel-ok` to the servers that support it - #2113

Respond with `basic.cancel-ok` to the servers that support it#2113
michaelklishin merged 5 commits into
mainfrom
mk-basic-cancel-ok-server-capability

michaelklishin commented Oct 6, 2026 •

edited

Loading

Uh oh!

Copilot AI left a comment

Uh oh!

michaelklishin commented Oct 6, 2026

Uh oh!

Uh oh!

michaelklishin commented Oct 6, 2026

Uh oh!

mergify Bot commented Oct 6, 2026 •

edited

Loading

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Conversation

michaelklishin commented Oct 6, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

The Server Part of the Changes

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Copilot review overview

🟡 Changes recommended

Uh oh!

michaelklishin commented Oct 6, 2026

Uh oh!

Uh oh!

michaelklishin commented Oct 6, 2026

Uh oh!

mergify Bot commented Oct 6, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

✅ Backports have been created

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

michaelklishin commented Oct 6, 2026 •

edited

Loading

mergify Bot commented Oct 6, 2026 •

edited

Loading