I'm trying to use kapt in my project and it is working well when I compile manually using maven. How...

# build-tools

[David Kubecka]

I'm trying to use kapt in my project and it is working well when I compile manually using maven. However, the Intellij IDEA integrated builder has trouble when compiling the generated sources. I've filed a bug to IDEA directly as I think the issue might be there (there's a simple reproducer project if anyone would be glad to look at it). To understand the issue more, I would like to know the reasoning behind and perhaps more details of this Maven/Kotlin guide that I followed. I noticed that when I don't "disable" the maven-compiler-plugin I get the same error during manual maven compilation ("package does not exist") as I get in IDEA when the pom is set up correctly.

Can anyone shed more light into this issue?

[Aleksei Cherepanov]

Hi! Can you please look into project structure and check, that path to generated sources is correctly marked as Source folders

[David Kubecka]

Yes, both kapt and kaptKotlin (although the latter is empty) are marked.

[Aleksei Cherepanov]

Then you should go to this location and if there is no com folder, compiler will not find it -
so you project tree should be like:

.
└── target
    ├── generated-sources
    │   ├── kapt
    │   │   ├── com
    │   │   │   └── example
    │   │   │       └── blazedemo
    │   │   │           └── views
    │   │   │               ├── AnimalViewBuilder.java
    │   │   │               ├── ...

[Aleksei Cherepanov]

because target/generated-sources/kapt is source root, and it will be the starting point for the compiler to look for packages

[David Kubecka]

Ah, I see. My dir structure looks little bit differently for the generated sources.

[David Kubecka]

So I changed it in the pom, reimported the project, the Source Foulders are synced and the native build now works. Thanks!

[David Kubecka]

Hmm, but now I have different problem: The manual compilation fails on

[WARNING] Duplicate source root: /target/generated-sources/kapt/compile

I have this in the pom:

<execution>
                        <id>compile</id>
                        <phase>compile</phase>
                        <goals>
                            <goal>compile</goal>
                        </goals>
                        <configuration>
                            <sourceDirs>
                                <sourceDir>src/main/kotlin</sourceDir>
                                <sourceDir>target/generated-sources/kapt/compile</sourceDir>
                            </sourceDirs>
                        </configuration>
                    </execution>

[Aleksei Cherepanov]

I think it is more about https://youtrack.jetbrains.com/issue/KT-15040/Support-Kapt-in-IDEA-build-system-JPS, as IDK any documented way about how to make both Gradle and JPS builds with kapt live in one project and don’t affect each other, as JPS does not support Kapt. And as soon as you change your pom file, it will affect either Gradle build or import and further JPS build

[Aleksei Cherepanov]

BTW it is strange that warning fails the build

[David Kubecka]

warning fails the build

I have it the compiler set to fail on warning.

[David Kubecka]

The issue with Duplicate source root is NOT IDEA specific. It happens when running maven manually (mvn compile)

[Aleksei Cherepanov]

Can you share your pom?

[David Kubecka]

Here's the updated pom from the KT issue

pom.xml

[David Kubecka]

The sourceDir is changed to target/generated-sources/kapt/compile which satisfies IDEA but breaks mvn compile

[Aleksei Cherepanov]

Looks like Kapt also added this source itself automatically

[David Kubecka]

But if I remove the sourceDir then I would expect that the generated classes are compiled into the classes folder, which they are not...

[David Kubecka]

It seems that I have to use the add-sources goal of the build-helper-maven-plugin. But then I don't understand why the source as added by kapt (as you say) doesn't get compiled...