Hi, I deployed a project made with https://start.spring.io / 17 in Java, Kotlin. The following problem arose, after the gradle synchronization, a problem arose - Some kotlin libraries connected to this project were compiled using a newer kotlin compiler.

build.gradle

import org.jetbrains.kotlin.gradle.tasks.KotlinCompile

plugins {
    id("org.springframework.boot") version "3.0.0-M1"
    id("io.spring.dependency-management") version "1.0.11.RELEASE"
    id("org.asciidoctor.convert") version "1.5.8"
    kotlin("jvm") version "1.6.10"
    kotlin("plugin.spring") version "1.6.10"
    kotlin("plugin.jpa") version "1.6.10"
}

group = "com.coursebit.server"
version = "0.0.1-SNAPSHOT"
java.sourceCompatibility = JavaVersion.VERSION_17

configurations {
    compileOnly {
        extendsFrom(configurations.annotationProcessor.get())
    }
}

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

val snippetsDir by extra { file("build/generated-snippets") }

dependencies {
    implementation("org.springframework.boot:spring-boot-starter-data-jdbc")
    implementation("org.springframework.boot:spring-boot-starter-data-jpa")
    implementation("org.springframework.boot:spring-boot-starter-data-ldap")
    implementation("org.springframework.boot:spring-boot-starter-jdbc")
    implementation("org.springframework.boot:spring-boot-starter-oauth2-client")
    implementation("org.springframework.boot:spring-boot-starter-oauth2-resource-server")
    implementation("org.springframework.boot:spring-boot-starter-security")
    implementation("org.springframework.boot:spring-boot-starter-web")
    implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
    implementation("org.jetbrains.kotlin:kotlin-reflect")
    implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
    compileOnly("org.projectlombok:lombok")
    developmentOnly("org.springframework.boot:spring-boot-devtools")
    runtimeOnly("mysql:mysql-connector-java")
    annotationProcessor("org.projectlombok:lombok")
    testImplementation("org.springframework.boot:spring-boot-starter-test")
    testImplementation("org.springframework.restdocs:spring-restdocs-mockmvc")
    testImplementation("org.springframework.security:spring-security-test")
}

tasks.withType<KotlinCompile> {
    kotlinOptions {
        freeCompilerArgs = listOf("-Xjsr305=strict")
        jvmTarget = "17"
    }
}

tasks.withType<Test> {
    useJUnitPlatform()
}

tasks.test {
    outputs.dir(snippetsDir)
}

tasks.asciidoctor {
    inputs.dir(snippetsDir)
    dependsOn(tasks.test)
}

Detailed error message

Comment From: snicoll

Thanks for getting in touch, but it feels like this is a question that would be better suited to Stack Overflow. As mentioned in the guidelines for contributing, we prefer to use GitHub issues only for bugs and enhancements. Feel free to update this issue with a link to the re-posted question (so that other people can find it) or add some more details if you feel this is a genuine bug.

Comment From: wilkinsona

@HotsHom Spring Boot 3.0.0-M1 requires Kotlin 1.6. As mentioned in the error message that you have shared, you need to upgrade the Kotlin plugin in your IDE.

We should mention this change to the minimum requirements in the release notes and reference documentation.

Comment From: pashabhai

@wilkinsona can i work on to upgrade relevant documentation?

Comment From: wilkinsona

Thanks for the offer, @pashabhai. We’ve found that documentation update often result in a contributor essentially copying and pasting a suggestion that we make into a pull request. That’s not satisfying for us or, more importantly, for the contributor. As such, we prefer to handle this sort of documentation update ourselves. Thanks anyway.