RESTEasy Reactive build failure with MULTIPART_FORM_DATA

[jsmrcka]

Describe the bug

Using quarkus-resteasy-reactive extension, I'm trying to do this:

@Path("/echo")
public class MyResource {
    @POST
    @Consumes(MediaType.MULTIPART_FORM_DATA)
    @Produces(MediaType.TEXT_PLAIN)
    public String echo(byte[] request) {
        return new String(request, StandardCharsets.UTF_8);
    }
}

which should be fine (works for non-reactive quarkus-resteasy).
But when I invoke mvn package, I get an exception:

[ERROR] Failed to execute goal io.quarkus.platform:quarkus-maven-plugin:2.1.2.Final:build (default) on project my-artifactId: Failed to build quarkus application: io.quarkus.builder.BuildException: Build failure: Build failed due to errors
[ERROR] 	[error]: Build step io.quarkus.resteasy.reactive.server.deployment.ResteasyReactiveProcessor#setupEndpoints threw an exception: java.lang.RuntimeException: java.lang.RuntimeException: Failed to process method org.my.group.MyResource#java.lang.String echo(byte[] request)
[ERROR] 	at org.jboss.resteasy.reactive.common.processor.EndpointIndexer.createEndpoints(EndpointIndexer.java:245)
[ERROR] 	at io.quarkus.resteasy.reactive.server.deployment.ResteasyReactiveProcessor.setupEndpoints(ResteasyReactiveProcessor.java:423)
[ERROR] 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[ERROR] 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
[ERROR] 	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[ERROR] 	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
[ERROR] 	at io.quarkus.deployment.ExtensionLoader$2.execute(ExtensionLoader.java:820)
[ERROR] 	at io.quarkus.builder.BuildContext.run(BuildContext.java:277)
[ERROR] 	at org.jboss.threads.ContextHandler$1.runWith(ContextHandler.java:18)
[ERROR] 	at org.jboss.threads.EnhancedQueueExecutor$Task.run(EnhancedQueueExecutor.java:2449)
[ERROR] 	at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1478)
[ERROR] 	at java.base/java.lang.Thread.run(Thread.java:829)
[ERROR] 	at org.jboss.threads.JBossThread.run(JBossThread.java:501)
[ERROR] Caused by: java.lang.RuntimeException: Failed to process method org.my.group.MyResource#java.lang.String echo(byte[] request)
[ERROR] 	at org.jboss.resteasy.reactive.common.processor.EndpointIndexer.createResourceMethod(EndpointIndexer.java:548)
[ERROR] 	at org.jboss.resteasy.reactive.common.processor.EndpointIndexer.createEndpoints(EndpointIndexer.java:293)
[ERROR] 	at org.jboss.resteasy.reactive.common.processor.EndpointIndexer.createEndpoints(EndpointIndexer.java:216)
[ERROR] 	... 12 more
[ERROR] Caused by: java.lang.NullPointerException
[ERROR] 	at io.quarkus.resteasy.reactive.server.deployment.QuarkusServerEndpointIndexer.handleMultipart(QuarkusServerEndpointIndexer.java:226)
[ERROR] 	at org.jboss.resteasy.reactive.common.processor.EndpointIndexer.createResourceMethod(EndpointIndexer.java:459)
[ERROR] 	... 14 more

Expected behavior

No response

Actual behavior

No response

How to Reproduce?

resteasy-reactive-multipart-reproducer.zip

unzip ./resteasy-reactive-multipart-reproducer.zip
cd ./resteasy-reactive-multipart-reproducer/
./mvnw clean package

Output of uname -a or ver

No response

Output of java -version

openjdk version "11.0.11" 2021-04-20 OpenJDK Runtime Environment AdoptOpenJDK-11.0.11+9 (build 11.0.11+9) OpenJDK 64-Bit Server VM AdoptOpenJDK-11.0.11+9 (build 11.0.11+9, mixed mode)

GraalVM version (if different from Java)

No response

Quarkus version or git rev

2.1.2.Final

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

Apache Maven 3.8.1 (05c21c65bdfed0f71a2f2ada8b84da59348c4c5d)

Additional information

No response

[quarkus-bot]

/cc @FroMage, @geoand, @stuartwdouglas