IntelliJ 无法识别 Kotlin noArg 插件

Question

I am not sure if I've missed a config or stumbled upon a bug. I am using IntelliJ to build a Kotlin Spring Boot application with JPA and would like to use Kotlin noArg plugin to reduce boilerplate in Entities.

With the build.gradle.kts below my application compiles OK but IntellJ underlines my Entity with error Class 'User' should have [public, protected] no-arg constructor .

Is there something I can set up in IntelliJ or build.gradle to make the error disappear?

System specs:

• Windows 11 + WSL
• IntelliJ IDEA 2021.3.1 (Ultimate Edition)
• Kotlin plugin 213-1.6.10-release-944-IJ6461.79

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

plugins {
    id("org.springframework.boot") version "2.6.4"
    id("io.spring.dependency-management") version "1.0.11.RELEASE"
    id("org.jetbrains.kotlin.plugin.noarg") version "1.6.10"
    kotlin("jvm") version "1.6.10"
    kotlin("plugin.spring") version "1.6.10"
    kotlin("plugin.jpa") version "1.6.10"
}

group = "XXXXXX"
version = "0.0.1-SNAPSHOT"
java.sourceCompatibility = JavaVersion.VERSION_16

repositories {
    mavenCentral()
}

dependencies {
    implementation("org.springframework.boot:spring-boot-starter-data-jpa")
    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")
    developmentOnly("org.springframework.boot:spring-boot-devtools")
    runtimeOnly("com.h2database:h2")
    testImplementation("org.springframework.boot:spring-boot-starter-test")
    testImplementation("org.springframework.security:spring-security-test")
}

noArg {
    annotation("javax.persistence.Entity")
}

tasks.withType<KotlinCompile> {
    kotlinOptions {
        freeCompilerArgs = listOf("-Xjsr305=strict")
        jvmTarget = "16"
    }
}

Answer 1

I had the same problem, but with my Maven project. The thing was in <executions> block. Maybe IDEA doesn't understand such complex configs yet. I removed it and kept this simple config.

<plugin>
    <groupId>org.jetbrains.kotlin</groupId>
    <artifactId>kotlin-maven-plugin</artifactId>
    <version>${kotlin.version}</version>
    <configuration>
        <sourceDirs>
            <sourceDir>${project.basedir}/src/main/kotlin</sourceDir>
            <sourceDir>${project.basedir}/src/main/java</sourceDir>
        </sourceDirs>
        <compilerPlugins>
            <plugin>jpa</plugin>
            <plugin>all-open</plugin>
            <plugin>spring</plugin>
        </compilerPlugins>
        <pluginOptions>
            <option>all-open:annotation=javax.persistence.Entity</option>
            <option>all-open:annotation=javax.persistence.Embeddable</option>
            <option>all-open:annotation=javax.persistence.MappedSuperclass</option>
        </pluginOptions>
        <args>
            <!-- https://docs.spring.io/spring-boot/docs/2.0.x/reference/html/boot-features-kotlin.html#boot-features-kotlin-null-safety -->
            <arg>-Xjsr305=strict</arg>
        </args>
    </configuration>
    <dependencies>
        <dependency>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-maven-noarg</artifactId>
            <version>${kotlin.version}</version>
        </dependency>
        <dependency>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-maven-allopen</artifactId>
            <version>${kotlin.version}</version>
        </dependency>
    </dependencies>
</plugin>

Answer 2

Turns out that it's a bug in IntelliJ running on WSL-based project.

I'm tracking the bug here https://youtrack.jetbrains.com/issue/KTIJ-21314/ and will update the answer once resolved.

Answer 3

你只需要重新加载项目，对我来说它在一个 Maven 项目中工作。