Simple native Kotlin function app fails to start in Docker - Could not resolve matching constructor

[frayneposset]

Describe the bug

Simple Kotlin function app fails to start in native docker image:

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'toUpperCase_registration': Could not resolve matching constructor (hint: specify index/type/name arguments for simple parameters to avoid type ambiguities)
        at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:279) ~[na:na]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1354) ~[na:na]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1204) ~[na:na]
        at org.springframework.beans.factory.support.AbstractAutowire

Sample
Write a simple Spring Boot Kotlin application with a simple function exposed as a bean.

Build then run in docker:

./gradlew build bootBuildImage

docker run functionnative:0.0.1-SNAPSHOT

Kotlin code:

package com.example.functionnative

import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.runApplication
import org.springframework.context.annotation.Bean

@SpringBootApplication
class FunctioningApplication {
	@Bean
	fun toUpperCase(): (String) -> String = { it.toUpperCase() }
}


fun main(args: Array<String>) {
	runApplication<FunctioningApplication>(*args)
}

build.gradle.kts :

import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
import org.springframework.boot.gradle.tasks.bundling.BootBuildImage

plugins {

	id("org.springframework.boot") version "2.4.4"
	id("io.spring.dependency-management") version "1.0.11.RELEASE"
	kotlin("jvm") version "1.4.30"
	kotlin("plugin.spring") version "1.4.30"
	id("org.springframework.experimental.aot") version "0.9.1-SNAPSHOT"
}

group = "com.example"
version = "0.0.1-SNAPSHOT"
java.sourceCompatibility = JavaVersion.VERSION_11

repositories {
	maven { url = uri("https://repo.spring.io/snapshot") }
	mavenCentral()
}

extra["springCloudVersion"] = "2020.0.2"

dependencies {
	implementation("org.springframework.boot:spring-boot-starter")
	implementation("org.springframework.boot:spring-boot-starter-web")
	implementation("org.jetbrains.kotlin:kotlin-reflect")
	implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
	listOf("context","kotlin","web").forEach {
		implementation("org.springframework.cloud:spring-cloud-function-$it")
	}
	testImplementation("org.springframework.boot:spring-boot-starter-test")
}

dependencyManagement {
	imports {
		mavenBom("org.springframework.cloud:spring-cloud-dependencies:${property("springCloudVersion")}")
	}
}

tasks.withType<KotlinCompile> {
	kotlinOptions {
		freeCompilerArgs = listOf("-Xjsr305=strict")
		jvmTarget = "11"
	}
}

tasks.withType<Test> {
	useJUnitPlatform()
}

tasks.withType<BootBuildImage> {
	builder = "paketobuildpacks/builder:tiny"
	environment = mapOf("BP_NATIVE_IMAGE" to "true")
}

[olegz]

Are you saying it only breaks in native docker image?

[frayneposset]

Yes, works ok normally, broken in native docker image.

[olegz]

@frayneposset I had a discussion with some of our guys on spring-native team and they advised to have this issue moved to https://github.com/spring-projects-experimental/spring-native/issues. Unfortunately we can't move issues across the orgs so I am going to close this and ask you to raise a new one in the provided link (you can still link to this issue form there)

Also, it would greatly speed up the resolution process if you can create a small repo in GitHub with a bare minimum to reproduce the issue, given that the actual problem could be anywhere (code, missing plugin etc) we need to have a view into your exact process.

[olegz]

Also, i was just told that org.springframework.experimental.aot:0.9.1 has just been released, so give it a try as well.

Last but not least I have a hint of my own and suspect that there may be issues with the class in question given the error you see Could not resolve matching constructor. It's private which is generally OK with spring dependency injection mechanisms, but could potentially be an issue with native, so i'll let you know when the new snapshots will be available.

[olegz]

Just an FYI. The new spring-cloud-function snapshots with the updated class is available

[frayneposset]

New issue raised with GIT repo example :

spring-attic/spring-native#652