REST Client fails for sub-resources with BeanParam

[jburkal]

Describe the bug

Since Quarkus 3.21.3, REST client interfaces fails to initialize if they have any methods with a @BeanParam annotated parameter that returns a sub-resource interface. The following exception is thrown:

java.lang.RuntimeException: Error injecting org.acme.subresourcebean.TestClient org.acme.subresourcebean.TestResource.client
        at org.acme.subresourcebean.TestResource_Bean.doCreate(Unknown Source)
        at org.acme.subresourcebean.TestResource_Bean.create(Unknown Source)
        at org.acme.subresourcebean.TestResource_Bean.create(Unknown Source)
        at io.quarkus.arc.impl.AbstractSharedContext.createInstanceHandle(AbstractSharedContext.java:119)
        at io.quarkus.arc.impl.AbstractSharedContext$1.get(AbstractSharedContext.java:38)
        at io.quarkus.arc.impl.AbstractSharedContext$1.get(AbstractSharedContext.java:35)
        at io.quarkus.arc.impl.LazyValue.get(LazyValue.java:32)
        at io.quarkus.arc.impl.ComputingCache.computeIfAbsent(ComputingCache.java:69)
        at io.quarkus.arc.impl.ComputingCacheContextInstances.computeIfAbsent(ComputingCacheContextInstances.java:19)
        at io.quarkus.arc.impl.AbstractSharedContext.get(AbstractSharedContext.java:35)
        at org.acme.subresourcebean.TestResource_Bean.get(Unknown Source)
        at org.acme.subresourcebean.TestResource_Bean.get(Unknown Source)
        at io.quarkus.arc.impl.ArcContainerImpl.beanInstanceHandle(ArcContainerImpl.java:570)
        at io.quarkus.arc.impl.ArcContainerImpl.beanInstanceHandle(ArcContainerImpl.java:550)
        at io.quarkus.arc.impl.ArcContainerImpl.beanInstanceHandle(ArcContainerImpl.java:583)
        at io.quarkus.arc.impl.ArcContainerImpl$3.get(ArcContainerImpl.java:337)
        at io.quarkus.arc.impl.ArcContainerImpl$3.get(ArcContainerImpl.java:334)
        at io.quarkus.arc.runtime.BeanContainerImpl$1.create(BeanContainerImpl.java:62)
        at io.quarkus.resteasy.reactive.common.runtime.ArcBeanFactory.createInstance(ArcBeanFactory.java:27)
        at org.jboss.resteasy.reactive.server.handlers.InstanceHandler.handle(InstanceHandler.java:26)
        at io.quarkus.resteasy.reactive.server.runtime.QuarkusResteasyReactiveRequestContext.invokeHandler(QuarkusResteasyReactiveRequestContext.java:139)
        at org.jboss.resteasy.reactive.common.core.AbstractResteasyReactiveContext.run(AbstractResteasyReactiveContext.java:147)
        at io.quarkus.vertx.core.runtime.VertxCoreRecorder$15.runWith(VertxCoreRecorder.java:638)
        at org.jboss.threads.EnhancedQueueExecutor$Task.doRunWith(EnhancedQueueExecutor.java:2675)
        at org.jboss.threads.EnhancedQueueExecutor$Task.run(EnhancedQueueExecutor.java:2654)
        at org.jboss.threads.EnhancedQueueExecutor.runThreadBody(EnhancedQueueExecutor.java:1627)
        at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1594)
        at org.jboss.threads.DelegatingRunnable.run(DelegatingRunnable.java:11)
        at org.jboss.threads.ThreadLocalResettingRunnable.run(ThreadLocalResettingRunnable.java:11)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.base/java.lang.Thread.run(Thread.java:840)
Caused by: org.eclipse.microprofile.rest.client.RestClientDefinitionException: org.jboss.resteasy.reactive.client.api.InvalidRestClientDefinitionException: Failed to generate client for class interface org.acme.subresourcebean.TestClient : Must be a Class or String, got null
        at io.quarkus.rest.client.reactive.runtime.RestClientBuilderImpl.build(RestClientBuilderImpl.java:595)
        at io.quarkus.rest.client.reactive.runtime.QuarkusRestClientBuilderImpl.build(QuarkusRestClientBuilderImpl.java:279)
        at io.quarkus.rest.client.reactive.runtime.RestClientCDIDelegateBuilder.build(RestClientCDIDelegateBuilder.java:74)
        at io.quarkus.rest.client.reactive.runtime.RestClientCDIDelegateBuilder.createDelegate(RestClientCDIDelegateBuilder.java:54)
        at io.quarkus.rest.client.reactive.runtime.RestClientReactiveCDIWrapperBase.delegate(RestClientReactiveCDIWrapperBase.java:76)
        at io.quarkus.rest.client.reactive.runtime.RestClientReactiveCDIWrapperBase.<init>(RestClientReactiveCDIWrapperBase.java:30)
        at org.acme.subresourcebean.TestClient$$CDIWrapper.<init>(Unknown Source)
        at org.acme.subresourcebean.TestClient$$CDIWrapper_ClientProxy.<init>(Unknown Source)
        at org.acme.subresourcebean.TestClient$$CDIWrapper_Bean.proxy(Unknown Source)
        ... 31 more
Caused by: org.jboss.resteasy.reactive.client.api.InvalidRestClientDefinitionException: Failed to generate client for class interface org.acme.subresourcebean.TestClient : Must be a Class or String, got null
        at org.jboss.resteasy.reactive.client.impl.ClientProxies.get(ClientProxies.java:31)
        at org.jboss.resteasy.reactive.client.impl.WebTargetImpl.proxy(WebTargetImpl.java:465)
        at io.quarkus.rest.client.reactive.runtime.RestClientBuilderImpl.build(RestClientBuilderImpl.java:593)
        ... 41 more

The cause of this exception happens at build time, but does not cause a build failure:

2025-05-12 09:14:21,323 DEBUG [io.qua.jax.cli.rea.dep.JaxrsClientReactiveProcessor] (build-10) Failed to create client proxy for org.acme.subresourcebean.TestClient this can usually be safely ignored: java.lang.IllegalArgumentException: Must be a Class or String, got null
        at io.quarkus.gizmo.DescriptorUtils.objectToDescriptor(DescriptorUtils.java:133)
        at io.quarkus.gizmo.FieldDescriptor.of(FieldDescriptor.java:44)
        at io.quarkus.gizmo.ClassCreator.getFieldCreator(ClassCreator.java:126)
        at io.quarkus.jaxrs.client.reactive.deployment.JaxrsClientReactiveProcessor.handleSubResourceMethod(JaxrsClientReactiveProcessor.java:1551)
        at io.quarkus.jaxrs.client.reactive.deployment.JaxrsClientReactiveProcessor.generateClientInvoker(JaxrsClientReactiveProcessor.java:932)
        at io.quarkus.jaxrs.client.reactive.deployment.JaxrsClientReactiveProcessor.setupClientProxies(JaxrsClientReactiveProcessor.java:423)
        at java.base/java.lang.invoke.MethodHandle.invokeWithArguments(MethodHandle.java:732)
        at io.quarkus.deployment.ExtensionLoader$3.execute(ExtensionLoader.java:856)
        at io.quarkus.builder.BuildContext.run(BuildContext.java:255)
        at org.jboss.threads.ContextHandler$1.runWith(ContextHandler.java:18)
        at org.jboss.threads.EnhancedQueueExecutor$Task.doRunWith(EnhancedQueueExecutor.java:2675)
        at org.jboss.threads.EnhancedQueueExecutor$Task.run(EnhancedQueueExecutor.java:2654)
        at org.jboss.threads.EnhancedQueueExecutor.runThreadBody(EnhancedQueueExecutor.java:1627)
        at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1594)
        at java.base/java.lang.Thread.run(Thread.java:840)
        at org.jboss.threads.JBossThread.run(JBossThread.java:499)

This used to work, but has failed since Quarkus version 3.21.3.

The most likely cause Is the changes introduced in #47368, specifically changing param.type to param.declaredType in the JaxrsClientReactiveProcessor#handleSubResourceMethod method.

Looking at this with a debugger, I can see that the declaredType field on the FieldDescriptor object is null, whereas the type field contains the correct class name.

Expected behavior

No response

Actual behavior

No response

How to Reproduce?

I've created a GitHub repository that reproduces this problem: https://github.com/jburkal/quarkus-beanparam-test

Specifically:

• Client: https://github.com/jburkal/quarkus-beanparam-test/blob/main/src/main/java/org/acme/subresourcebean/TestClient.java
• Sub-resource: https://github.com/jburkal/quarkus-beanparam-test/blob/main/src/main/java/org/acme/subresourcebean/SubClient.java
• Bean parameter: https://github.com/jburkal/quarkus-beanparam-test/blob/main/src/main/java/org/acme/TestBean.java

Output of uname -a or ver

No response

Output of java -version

No response

Quarkus version or git rev

3.21.3

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

No response

Additional information

No response

[quarkus-bot]

/cc @cescoffier (rest-client), @geoand (rest-client)

[geoand]

@Postremus might be interested in this since he's done a lot of great work lately in this area

[Postremus]

@geoand Summer has started in germany, at least thats what it feels like. Please don't count on anymore contributions from my side until winter.

But thank you for thinking about me :)

[geoand]

Thanks for the heads up!

[geoand]

@jburkal as you seem to have done some nice detective work here, are you willing perhaps to come up with a fix?

[jburkal]

@geoand, I won't mind giving it a try :)

Ideally, this could be fixed by changing param.declaredType to someting like Objects.requireNonNullElse(param.declaredType, param.type) (and adding tests), but I won't be happy with such a solution unless I know why this failed in this manner.

[geoand]

@jburkal I actually am about to open a PR :)

[geoand]

See #47909