Duplicate generated class gradle output (build/...) vs intellij output (out/...) - gradle

Question

I'm using intellij (2019.1.1) for a java gradle (5.4.1) project and use lombok (1.18.6) for autogenerating code. Intellij puts generated sources under out/production/classes/generated/... and gradle puts them under build/generated/sources/...
This is fine, and I like that intellij keeps it's own build artifacts separate from gradles, however, intellij seems to look in both directories when running projects and it complains about the duplicate generated classes.
What is the best practice for using intellij with gradle and autogenerated sources? Do you:
tell intellij to output to the same directory as gradle (this
could lead to odd behaviour if a process outside of intellij updates
a file under build/)
tell intellij to perform all tasks with
gradle (i hear this is slower than intellij's make)
tell intellij
to simply ignore the 'build' directory (how do you even do this? and
why does intellij even care about 'build/' when it knows it outputs
to 'out/')
UPDATE: to clarify the situation, the issue is NOT with lombok autogenerated code, it is with hibernate-jpamodelgen. The problem remains the same (duplicate generated sources) but I want to clarify the it is the sources generated by jpamodelgen and not lombok.
UPDATE 2: I have tried the following configuration in an attempt to tell intellij where the generated sources live and also to tell intellij to ignore the build directory. Sadly, this did not work (still get duplicate class error on the generated source files).
apply plugin: 'idea'
idea {
module {
sourceDirs += file('out/production/classes/generated')
generatedSourceDirs += file('out/production/classes/generated')
excludeDirs += file('build')
}
}
UPDATE 3:
Tried the advice from M.Riccuiti and deleted build/, out/, .idea/, .gradle/ and reimported the gradle project but intellij is still seeing the generated sources in the build/ directory.

Answer 1

Here is an approach that finally worked for me. The trick is to notice that when gradle generates the classes, it puts them in:
build\generated\sources\annotationProcessor\java\main\com...
but intellij has the production sources directory set to "generated" in this case, the sources go to:
build\generated\sources\annotationProcessor\java\main\generated\com...
if you compile with gradle first and then use idea, you get both of them, which causes the problem!
To solve this, replace "generated" and "generated_test" in the intellij annotation processors "production sources directory " and "test sources directory " configuration with just a "/" this makes both gradle and intellij generate the sources in the SAME directory, overwriting each other as needed. Also make sure that the "store generated sources relative to" is set to "module content root" and REBUILD the application to clear out any other sources.

Answer 2

The solution I proposed in previous comment was working fine in IDEA 2018.3.x but after upgrading to IDEA 2019.1 I again got this duplicate class exception...
Below is a working solution to make this work with Gradle 5.x (tested with 5.4) and IDEA 2019.1 , to implement your solution #3 which I think is the best option (do not mix gradle & idea generated output directories, and do not delegate IDEA action do Gradle )
The key point is to use excludeDirs property from idea.module extension to make IDEA ignore generated sources managed by Gradle under build/generated/sources/...
ext {
// path to Gradle generated main sources directory
gradleGeneratedMainSourcesDir = "$buildDir/generated/sources/annotationProcessor/java/main/"
// path to Gradle generated test sources directory
gradleGeneratedTestSourcesDir = "$buildDir/generated/sources/annotationProcessor/java/test/"
// path to IDEA generated sources directory
ideaGeneratedSourcesDir = "$projectDir/out/production/classes/generated"
}
idea {
module {
// exclude main & test sources generated by Gradle from project source directories
excludeDirs += file(gradleGeneratedMainSourcesDir)
excludeDirs += file(gradleGeneratedTestSourcesDir)
// include generated sources directory managed by IDEA
sourceDirs += file(ideaGeneratedSourcesDir)
generatedSourceDirs += file(ideaGeneratedSourcesDir)
}
}
See complete sample project based on this configuration here : https://github.com/mricciuti/sample-springboot-gradle-idea

Answer 3

You can enter to IntelliJ Settings (Preferences):
Preferences | Build, Execution, Deployment | Build Tools | Gradle | Runner
Then you tick the checkbox Delegate IDE build/run action to Gradle
Finally, you clean and build again. The issues will be resolved.