How do I set up APT for Immutables such that Intellij Idea will recognize the generated code?

Question

I'm looking into migrating from maven to gradle, in this case, gradle itself seems to be working fine, but Idea isn't recognizing the source code that Immutables is generating.

I've read this blog post on APT, it's how I got this for.

/*
 * This build file was generated by the Gradle 'init' task.
 *
 * This generated file contains a commented-out sample Java project to get you started.
 * For more details take a look at the Java Quickstart chapter in the Gradle
 * user guide available at https://docs.gradle.org/4.3/userguide/tutorial_java_projects.html
 */


// Apply the java plugin to add support for Java
apply plugin: 'java-library'
apply plugin: 'idea'

buildscript {
    repositories {
        maven {
            url 'https://d3vfm0n2cffdwd.cloudfront.net'
        }
        jcenter()
    }
    dependencies {
        classpath 'io.spring.gradle:dependency-management-plugin:1.0.0.RELEASE'
    }
}

apply plugin: 'io.spring.dependency-management'

dependencyManagement {
    imports {
        mavenBom 'com.xenoterracide:platform:0.1.39-SNAPSHOT'
    }
}

repositories {
    maven {
        url 'https://d3vfm0n2cffdwd.cloudfront.net'
    }
    jcenter()
}

configurations {
    apt
    aptCompile
}

// In this section you declare the dependencies for your production and test code
dependencies {
    implementation 'com.google.guava:guava'

    aptCompile 'org.immutables:value'
    compileOnly 'org.immutables:value'
    apt 'org.immutables:builder'

    // The production code uses the SLF4J logging API at compile time
    implementation 'org.slf4j:slf4j-api'

    // Declare the dependency for your favourite test framework you want to use in your tests.
    // TestNG is also supported by the Gradle Test task. Just change the
    // testCompile dependency to testCompile 'org.testng:testng:6.8.1' and add
    // 'test.useTestNG()' to your build script.
    testImplementation 'junit:junit'
    testImplementation 'org.assertj:assertj-core'
    testImplementation 'org.mockito:mockito-core'
    testImplementation 'org.hamcrest:hamcrest-library'
}

compileJava {
    options.annotationProcessorPath = configurations.aptCompile
}

for more code see bitbucket

one of the things that's getting me, is that depending on what I've tried the generated java either ends up in an out directory, or build on the classpath, of course so far neither of these solves the problem.

how do I fix this so that Idea can see the source for the generated types (so that it's not all highlighted in red)?

Answer 1

@CrazyCoder's links helped me get closer to a solution, this seems to resolve it though.

idea {
    module {
        sourceDirs += file("out/production/classes/generated")
    }
}