Autogenerated (AnnotationProcessor) interface not being "indexed/processed"

[nbrugger-tgm]

Expected Behavior

When you have an annotation processor that generates files like this:

import io.micronaut.http.annotation.Get;

public interface PingService {
    @Get("/ping")
    String ping();
}

and then manually add the implementation

import io.micronaut.http.annotation.Controller;

@Controller
public class PingResource implements PingService {
    @Override
    public String ping() {
        return "pong";
    }
}

The path /ping should be:

• [ ] available via the management endpoint /paths (if management is added ofc)
• [ ] be included in the generated OAS/Swagger file
• [ ] Be useable (curl for example)

Actual Behaviour

The path /ping path is:

• [ ] available via the management endpoint /paths (if management is added ofc)
• [x] included in the generated OAS/Swagger file
• [ ] Be useable (curl for example)

When changing the processor to generate this instead : (Adding the @Controller annotation to the interface)

package com.niton.localadmin.rest.controller;

import io.micronaut.http.annotation.*;

@Controller
public interface PingService {
    @Get("/ping")
    String ping();
}

the Open API generation works.

In Depth

• The example works if the PingService interface is in the main src dir src/main/java
• The cause seems to be that the PingResource$Definition$Exec file is missing after compilation which is present when the file is "hand written".
• The PingResource$Definition$Exec re-appears if i add a new method to the class that is annotated with an HTTP annotation. The old method ping() is still not present within the $Exec class
• Annotating the ping() method in the implementation class with @Get("/ping") makes the path available via /path and curl but does not include it into the OAS (except the controller annotation is placed on the interface itself)

This one is a pretty wild guess from my side and i have no clue if i am right but this is my guess without having had a deep dive into the sourcecode

This is what i think is causing the bug :

• Micronaut annotation processes the src/main/java PingResource and cant find any anotated method since the interface does not exist yet
• My annotation processor kicks in and generates the API interface PingService
• Micronaut notices the generation (since autogenerated classes are still annotation processed)
• Micronaut does not do anything because it only generates $Exec files for classes (reasonable, also it wouldnt even help)
• Micronaut OpenApi also processes the interface, but since OpenApi doesnt care (which is good) if it is a class or an interface it correctly generates the .yml if there is a @Controller annotation

Again this is just an educated guess but since i did a little tiny bit of debugging i think it might still be valueable to you :)

Steps To Reproduce

1. Generate micronaut app with features management and openapi (gradle)
2. Add a gradle subproject called processor_of_death
3. Add the aforementioned subproject to the micronaut app as annotationProcessor(project(":processor_of_death")) and also for the implementation config
4. Add this annotation processor to the processor_of_death project (imports omitted)

   
   package com.example.processor;

@SupportedAnnotationTypes("io.micronaut.http.annotation.Controller") public class DtoInterfaceGenerator extends AbstractProcessor { @Override public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) { try (var writer = processingEnv.getFiler().createSourceFile("com.example.controller.PingService").openWriter()) { writer.append("package com.niton.localadmin.rest.controller;\n" + "\n" + "import io.micronaut.http.annotation.*;\n" + "\n" + "@Controller\n" + "public interface PingService {\n" + "\t@Get(\"/ping\")\n" + "\tString ping();\n" + "}\n"); } catch (IOException e) { e.printStackTrace(); } return false;//false to make the interface processable by others } }

5. Register the Processor using *SPI*
6. Add the interface implementation to the micronaut project
```java
@Controller
public class PingResource implements PingResource.PingService {
    @Override
    public String ping() {
        return "pong";
    }

}

7. (optional) take the regarding steps to set up OpenApi processing from the micronaut doc here
8. Run the micronaut project
9. curl -X GET http://localhost:8080/ping will fail with 404 path not found ....
10. Remove the annotation processor
11. Add the interface to the micronautproject
12. restart
13. curl -X GET http://localhost:8080/ping will now work

Environment Information

• OS: Windows/WSL, Ubuntu (tried both)
• Build System: Gradle 7.2
• JDK: 17
• JRE: 17 & 17 (IBM semru)

Example Application

github.com/nbrugger-tgm

Version

3.3.1

[nbrugger-tgm]

Workaround

I found a workaround to get the expected result.

Split your project into 2 parts api and service or app where api is a micronaut lib that contains all the annotation processed code. And app is ... well, the app and contains the implementation of the api. This is the only reliable way to force annotation processor order, still it would be favorable to work out of the box

[nbrugger-tgm]

Related: https://github.com/micronaut-projects/micronaut-openapi/pull/750

[nbrugger-tgm]

Hi, don't want to be inpatient, and i do not ask for this to be fixed, but it would be very kind to get an answer if this is a bug or working as intended.

[dstepanov]

Can you please create an example project

[nbrugger-tgm]

Sure, sorry for not doing this earlier

here you go: https://github.com/nbrugger-tgm/micronaut-reproductions/ Folder : 6918 (ticket number)

There is a testscript to be executed as soon as the api is started using ./gradlew run called test.sh

This is the most minimal that i managed to produce