Micronaut declarative http-client not injected in Grails 5.1.6 controllers / services

Question

I migrated an app from Grails 4.0.0 to Grails 5.1.6, it is using the Micronaut declarative client to make requests to an external API. When I run it with grails run-app it works fine, but when I generate the war with grails war and deploy it to a Tomcat container the Micronaut client is not injected correctly, when a controller action is called it throws the exception:

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'example.grails.HomeController': Unsatisfied dependency expressed through field 'appForgeClient'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'example.grails.GrailsAppForgeClient' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

Do you have an idea why it is not injected / found?

I am using:

• Grails 5.1.6
• openjdk 11.0.14.1
• tomcat:8.5-jdk11-openjdk

Sample app https://github.com/solaechea/SampleMicronautClientApp

build.gradle

compileOnly "io.micronaut:micronaut-inject-groovy"
implementation 'io.micronaut:micronaut-http-client'

application.yml

micronaut:
    http:
        services:
            backend:
                urls:
                    - https://start.grails.org
                path: /
                read-timeout: 1m
                read-idle-timeout: 1m
                max-content-length: 1mb

GrailsAppForgeClient.groovy (Declarative client)

import io.micronaut.http.annotation.Get
import io.micronaut.http.client.annotation.Client

@Client("backend")
interface GrailsAppForgeClient {

    @Get("/{version}/profiles")
    List<Map> profiles(String version)
}

HomeController.groovy

import grails.converters.JSON
import org.springframework.beans.factory.annotation.Autowired

class HomeController {
    @Autowired GrailsAppForgeClient appForgeClient

    def profiles() {
        String grailsVersion = '5.1.6'
        render(appForgeClient.profiles(grailsVersion) as JSON)
    }
}