Reactive REST Client breaks with ClassFormatError if attribute is present in interface

[markusdlugi]

Describe the bug

Since Quarkus 2.5.1.Final we experience a regression that the Reactive REST Client is not able to handle attributes in the interface annotated with @RegisterRestClient anymore. For example, the user might want to statically initialize variables for default methods provided in the interface. This previously worked with Quarkus 2.5.0.Final and earlier versions, but doesn't anymore.

Expected behavior

The REST Client should work even when (static) attributes are present in the interface.

Actual behavior

Any call to the REST client results in the following exception:

2022-01-19 13:12:37,836 ERROR [io.qua.ver.htt.run.QuarkusErrorHandler] (vert.x-eventloop-thread-2) HTTP Request to /test failed, error id: 403e59c7-1090-401b-b7ea-a86967eca787-1: java.lang.ClassFormatError: Method <clinit> is not static in class file com/example/SomeApi$$CDIWrapper
	at java.base/java.lang.ClassLoader.defineClass1(Native Method)
	at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1017)
	at io.quarkus.bootstrap.classloading.QuarkusClassLoader.loadClass(QuarkusClassLoader.java:445)
	at io.quarkus.bootstrap.classloading.QuarkusClassLoader.loadClass(QuarkusClassLoader.java:405)
	at java.base/java.lang.ClassLoader.defineClass1(Native Method)
	at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1017)
	at io.quarkus.bootstrap.classloading.QuarkusClassLoader.loadClass(QuarkusClassLoader.java:445)
	at io.quarkus.bootstrap.classloading.QuarkusClassLoader.loadClass(QuarkusClassLoader.java:405)
	at com.example.SomeApi$$CDIWrapper_Bean.proxy(Unknown Source)
	at com.example.SomeApi$$CDIWrapper_Bean.get(Unknown Source)
	at com.example.SomeApi$$CDIWrapper_Bean.get(Unknown Source)
	at com.example.TestResource_Bean.create(Unknown Source)
	at com.example.TestResource_Bean.create(Unknown Source)
	...

How to Reproduce?

Reproducer: https://github.com/markusdlugi/rest-client-attributes

Steps to reproduce the behavior:

1. Start application and send request GET http://localhost:8080/test
2. Observe failure in application logs
3. Remove line 26 in com.example.SomeApi and re-test
4. Observe that REST call is performed correctly

Output of uname -a or ver

Microsoft Windows [Version 10.0.19042.631]

Output of java -version

OpenJDK 64-Bit Server VM Corretto-11.0.10.9.1 (build 11.0.10+9-LTS, mixed mode)

GraalVM version (if different from Java)

N/A

Quarkus version or git rev

2.6.2.Final (regression started in 2.5.1.Final)

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

Apache Maven 3.6.3

Additional information

No response

[quarkus-bot]

/cc @michalszynkiewicz

[geoand]

This has actually already been fixed in main

[gsmet]

@geoand can the fix be backported? Maybe it already is?

[geoand]

You mean backported to 2.7 or 2.6?