RESTEasy Singleton resource with constructor injection failing with RESTEASY003190

[chris-asl]

Describe the bug

When using constructor injection in a non annotated resource (reproducer link), e.g.

@Path("/hello")
public class GreetingResource {

    GreetingService greetingService;

    @Inject
    public GreetingResource(GreetingService greetingService) {
        this.greetingService = greetingService;
    }

the program spins up successfully.

Given the default resource scope, as defined by quarkus.resteasy.singleton-resources is Singleton, why do I get an error if I annotate the class with @Singleton, as I did here?

The program fails upon startup with:

...
Caused by: java.lang.RuntimeException: RESTEASY003190: Could not find constructor for class: org.acme.getting.started.GreetingResource
	at org.jboss.resteasy.spi.metadata.ResourceBuilder.getConstructor(ResourceBuilder.java:852)
...

It seems there's a difference with explicitly setting the scope to Singleton with it being set-up "automatically".
If I am missing something, a pointer towards the docs would be more than welcome.

I don't know if this is related to #6722 or #7495.

Expected behavior

As in both cases the scope effectively is Singleton, shouldn't the behaviour be the same?

Actual behavior

Annotating a RESTEasy Resource with @Singleton, I get the aforementioned error.

To Reproduce

Link to a small reproducer (preferably a Maven project if the issue is not Gradle-specific).

Or attach an archive containing the reproducer to the issue.

Steps to reproduce the behavior:

1. git clone [email protected]:chris-asl/quarkus-mcve.git
2. ./mvnw quarkus:dev

Configuration

Defaults

Environment:

Output of uname -a or ver

Linux homer 5.8.0-48-generic #54~20.04.1-Ubuntu SMP Sat Mar 20 13:40:25 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

Output of java -version

openjdk version "11.0.10" 2021-01-19
OpenJDK Runtime Environment (build 11.0.10+9-Ubuntu-0ubuntu1.20.04)
OpenJDK 64-Bit Server VM (build 11.0.10+9-Ubuntu-0ubuntu1.20.04, mixed mode, sharing)

Quarkus version or git rev

1.13.1.Final (also tested with 1.12.2.Final)

Build tool

Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f)
Maven home: /home/chris/.m2/wrapper/dists/apache-maven-3.6.3-bin/1iopthnavndlasol9gbrbg6bf2/apache-maven-3.6.3
Java version: 11.0.10, vendor: Ubuntu, runtime: /usr/lib/jvm/java-11-openjdk-amd64
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "5.8.0-48-generic", arch: "amd64", family: "unix"

FYI @el10686

[quarkus-bot]

/cc @manovotn, @mkouba

[mkouba]

I can confirm that the behavior varies. If there is no scope annotation present then the no-args constructor is generated automatically. However, if the javax.inject.Singleton is added you need to add the no-args constructor manually. It's interesting that if you add @RequestScoped the no-args constructor is also generated although I don't see the javax.enterprise.context package in the list of compatible annotations here: https://github.com/quarkusio/quarkus/blob/main/extensions/resteasy-classic/resteasy-server-common/deployment/src/main/java/io/quarkus/resteasy/server/common/deployment/ResteasyServerCommonProcessor.java#L452-L463

CC @geoand

[mkouba]

It's interesting that if you add @RequestScoped the no-args constructor is also generated although I don't see the javax.enterprise.context package in the list of compatible annotations here...

In this case, the no-args constructor is generated by ArC because @RequestScoped is a normal scope.

[mkouba]

@geoand I think that we could just add the javax.inject to the list of compatible packages. I can send a PR tomorrow.

[geoand]

@mkouba yeah, that makes perfect sense!