无法使用 AutoValue 和 IntelliJ 解析符号

Question

I have been trying to find the correct settings for IntelliJ's annotation processing in order for it to co-exist with Gradle's build process.

Whenever I build from IntelliJ I cannot get it to recognise the generated sources from the gradle-apt-plugin .

My requirements for my project are:

• Building between IntelliJ and Gradle should be seamless and not interfere with the process of each other
• I need to use IntelliJ's Create separate module per source set option
• I need to use IntelliJ's folder based structure
• IntelliJ needs to be able to recognise and autocomplete AutoValue classes

Here are the steps for a MCVE in order to reproduce the issue with IntelliJ 2017.2.4 and Gradle 3.5:

• Create a new Gradle project from IntelliJ
• Check the Create separate module per source set option
• Open build.gradle file:
• Add the following plugins block:

plugins {
    id 'java'
    id 'net.ltgt.apt' version '0.12'
}

• Add the following dependencies block

dependencies {
    compileOnly 'com.google.auto.value:auto-value:1.5'
    apt 'com.google.auto.value:auto-value:1.5'
}

• Go to Settings → Build, Execution, Deployment → Annotation Processors
• Check the Enable Annotation Processing
• Create a class:

@AutoValue
public abstract class GeneratedSourcesTest {

    static GeneratedSourcesTest create(String field) {
        return new AutoValue_GeneratedSourcesTest(field);
    }

    public abstract String field();
}

• On IntelliJ run Build → Build Project
• Open the GeneratedSourcesTest class, on the static factory method, everything compiles fine but I get the error:

cannot resolve symbol 'AutoValue_GeneratedSourcesTest'

How can I make the AutoValue_GeneratedSourcesTest class accessible from IntelliJ?

Answer 1

After importing your Gradle project under IDEA do the following steps:

1. Set annotation processing configuration as follows:

2. Run menu: Build - Build Project

3. Right click on each new generated folder and select: Mark Directory as - Generated Sources Root so it was marked as follows:

   4. Add /generated to project's .gitignore file

That's a minimal viable configuration which will provide full IDE support for generated classes. The drawback is, whenever Gradle project gets re-imported the generated folders will need be marked as Generated Sources Root again. Perhaps this can be improved with adding these paths as source sets under build.gradle .

Sometimes it happens that IDEA modules lose their compiler output path settings in result of the above. It's sufficient to just set it back to their default folders.

Answer 2

The answers are (should be) in the README for the gradle-apt-plugin: https://github.com/tbroyer/gradle-apt-plugin

Namely, also apply the net.ltgt.apt-idea plugin.

Btw, I recommend delegating build/run actions to Gradle in IntelliJ. Sure it's a bit slower, but requires zero setup in the IDE and works reliably. That said, it should also work OK if you don't.

Answer 3

Just have your build.gradle with these and it works fine, no need of touching intellij, source set etc..

    plugins {
    id 'java'
    id "net.ltgt.apt" version "0.20"

}

apply plugin: 'idea'
apply plugin: 'net.ltgt.apt-idea'
group 'abc'
version '1.0-SNAPSHOT'

sourceCompatibility = 1.8

repositories {
    mavenCentral()
}

dependencies {
    testCompile group: 'junit', name: 'junit', version: '4.12'
    compile             "com.google.auto.value:auto-value-annotations:1.6.2"
    annotationProcessor "com.google.auto.value:auto-value:1.6.2"
}

Answer 4

I didn't have to do anything to intellij using maven by adding the optional true tag.

<dependency>
    <groupId>com.google.auto.value</groupId>
    <artifactId>auto-value</artifactId>
    <version>1.9</version>
    <optional>true</optional>
</dependency>