Config Error with Quarkus 2.0

[oo00spy00oo]

Describe the bug

In Migration Guide 2.0, I found:
Mapping of YAML Configuration to complex objects has been removed from io.quarkus.arc.config.ConfigProperties. Please use io.smallrye.config.ConfigMapping instead which is a safer alternative.

But I have an issue bellow, and I must revert to io.quarkus.arc.config.ConfigProperties to solve the issue.

        at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
        at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
        at io.quarkus.bootstrap.runner.RunnerClassLoader.loadClass(RunnerClassLoader.java:104)
        at io.quarkus.bootstrap.runner.RunnerClassLoader.loadClass(RunnerClassLoader.java:60)
        at io.smallrye.config.ConfigMappingClass.<init>(ConfigMappingClass.java:35)
        at io.smallrye.config.ConfigMappingClass.createConfigurationClass(ConfigMappingClass.java:27)
        at io.smallrye.config.ConfigMappingClass.access$000(ConfigMappingClass.java:7)
        at io.smallrye.config.ConfigMappingClass$1.computeValue(ConfigMappingClass.java:11)
        at io.smallrye.config.ConfigMappingClass$1.computeValue(ConfigMappingClass.java:8)
        at java.base/java.lang.ClassValue.getFromHashMap(ClassValue.java:226)
        at java.base/java.lang.ClassValue.getFromBackup(ClassValue.java:208)
        at java.base/java.lang.ClassValue.get(ClassValue.java:114)
        at io.smallrye.config.ConfigMappingClass.getConfigurationClass(ConfigMappingClass.java:17)
        at io.smallrye.config.ConfigMappingLoader.getConfigMappingClass(ConfigMappingLoader.java:42)
        at io.smallrye.config.ConfigMappingProvider$Builder.addRoot(ConfigMappingProvider.java:888)
        at io.smallrye.config.ConfigMappings.mapConfiguration(ConfigMappings.java:52)
        at io.smallrye.config.ConfigMappings.registerConfigMappings(ConfigMappings.java:36)
        at io.quarkus.arc.runtime.ConfigRecorder.registerConfigMappings(ConfigRecorder.java:50)
        at io.quarkus.deployment.steps.ConfigBuildStep$registerConfigClasses-2116437784.deploy_0(ConfigBuildStep$registerConfigClasses-2116437784.zig:132)
        at io.quarkus.deployment.steps.ConfigBuildStep$registerConfigClasses-2116437784.deploy(ConfigBuildStep$registerConfigClasses-2116437784.zig:40)
        at io.quarkus.runner.ApplicationImpl.doStart(ApplicationImpl.zig:864)
        at io.quarkus.runtime.Application.start(Application.java:101)
        at io.quarkus.runtime.ApplicationLifecycleManager.run(ApplicationLifecycleManager.java:101)
        at io.quarkus.runtime.Quarkus.run(Quarkus.java:66)
        at io.quarkus.runtime.Quarkus.run(Quarkus.java:42)
        at io.quarkus.runtime.Quarkus.run(Quarkus.java:119)
        at io.quarkus.runner.GeneratedMain.main(GeneratedMain.zig:29)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at io.quarkus.bootstrap.runner.QuarkusEntryPoint.doRun(QuarkusEntryPoint.java:48)
        at io.quarkus.bootstrap.runner.QuarkusEntryPoint.main(QuarkusEntryPoint.java:25)
  

Expected behavior

Using io.smallrye.config.ConfigMapping without any problems.

Actual behavior

No response

How to Reproduce?

package <redact>;

import io.quarkus.arc.config.ConfigProperties;
import lombok.Getter;
import lombok.Setter;

import java.util.List;

@Getter
@Setter
@ConfigMapping(prefix = "nats")
public class NatsConfig {
    List<String> servers;
}

application.yml:

nats:
  servers:
    - 0.0.0.0:4222

Output of uname -a or ver

Linux

Output of java -version

openjdk version "11.0.9" 2020-10-20 OpenJDK Runtime Environment AdoptOpenJDK (build 11.0.9+11) OpenJDK 64-Bit Server VM AdoptOpenJDK (build 11.0.9+11, mixed mode)

GraalVM version (if different from Java)

No response

Quarkus version or git rev

2.0.1.Final

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

Gradle

Additional information

No response

[geoand]

@radcortez has this already been fixed?

[radcortez]

Looking into the reproducer code, the @ConfigMapping annotation only applies to interfaces, not classes. I'll check if the current case is working with interfaces.

We probably need to add an explicit warning that the annotation only works with interfaces.

[radcortez]

I confirm that the same code with the expected interface works as expected. I'll add a warning (or a better exception) to prevent the mistake.

[radcortez]

Implemented in smallrye/smallrye-config#619

[radcortez]

@oo00spy00oo let us know if replacing the class with the interface works. Please, check the docs here: https://quarkus.io/guides/config-mappings#config-mappings

[oo00spy00oo]

@oo00spy00oo let us know if replacing the class with the interface works. Please, check the docs here: https://quarkus.io/guides/config-mappings#config-mappings

Thanks @radcortez