Kafka fails with mutiple emitters on same channel

[mocenas]

Describe the bug

Using kafka and avro. When creating more than one emitter per channel, it will fail to start, because of "different configuration for emitters", see exception below.

MovieResourceTest.testHelloEndpoint » Runtime java.lang.RuntimeException: io.quarkus.builder.BuildException: Build failure: Build failed due to errors
	[error]: Build step io.quarkus.smallrye.reactivemessaging.deployment.SmallRyeReactiveMessagingProcessor#build threw an exception: jakarta.enterprise.inject.spi.DeploymentException: Emitter configuration for channel `movies` is different than previous configuration : QuarkusEmitterConfiguration{name='movies', emitterType=io.quarkus.smallrye.reactivemessaging.runtime.EmitterFactoryForLiteral@7dd87975, overflowBufferStrategy=BUFFER, overflowBufferSize=-1, broadcast=false, numberOfSubscriberBeforeConnecting=-1}
	at io.quarkus.smallrye.reactivemessaging.deployment.SmallRyeReactiveMessagingProcessor.build(SmallRyeReactiveMessagingProcessor.java:302)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at io.quarkus.deployment.ExtensionLoader$3.execute(ExtensionLoader.java:849)
	at io.quarkus.builder.BuildContext.run(BuildContext.java:256)
	at org.jboss.threads.ContextHandler$1.runWith(ContextHandler.java:18)
	at org.jboss.threads.EnhancedQueueExecutor$Task.run(EnhancedQueueExecutor.java:2513)
	at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1538)
	at java.base/java.lang.Thread.run(Thread.java:840)
	at org.jboss.threads.JBossThread.run(JBossThread.java:501)

Although the emitters are declared exactly same:

@Channel("movies")
Emitter<Movie> emitter;

@Channel("movies")
Emitter<Movie> emitter2;

Removing one of these, makes the app work fine.

Expected behavior

Two emitters for same channel should cause no problem. It is even exampled in the docs https://quarkus.io/blog/reactive-messaging-emitter/#overflow-management

Actual behavior

Adding more than one emitter to the outgoing channel causes the app to fail to deploy. It is no matter if the two emitters are in same class / resource or not.

How to Reproduce?

I've created a reproducer on https://github.com/mocenas/quarkus-kafka-reproducer.
Install locally quarkus and run tests on it.

Output of uname -a or ver

No response

Output of java -version

opendjk 17.0.9

Quarkus version or git rev

999-SNAPSHOT rev. 2e6fe10

Build tool (ie. output of mvnw --version or gradlew --version)

No response

Additional information

Quarkus version 3.6.4 is not affected by this. Only 999-SNAPSHOT is. I cannot pinpoint exact PR which caused this, but we started to see this failure in daily tests between 2-3 of January 2024.

[quarkus-bot]

/cc @alesj (kafka), @cescoffier (kafka), @ozangunalp (kafka)

[ozangunalp]

Thanks for the reproducer, indeed it looks like a bug.

The check was introduced because you cannot declare multiple emitters with different configurations.
The overflow management section just gives a couple examples of overflow configurations.