Room + napt = javax.annotation.processing.FilerException: Attempt to recreate a file for type

[bacecek]

Hi!
I have applied your plugin in module with Room and got the next issue:

Preparations:
Let's assume we have module with build.gradle like this:

plugins {
    id 'com.android.application'
    id 'com.sergei-lapin.napt'
}

dependencies {
    annotationProcessor 'androidx.room:room-compiler:2.4.3'
    implementation 'androidx.room:room-runtime:2.4.3'
}

And we have the sample project from tutorial: https://developer.android.com/training/data-storage/room#java.

Steps:

1. Successful compilation of module
2. Make some changes to any source file
3. Recompile the module

Result:

* What went wrong:
Execution failed for task ':app:compileDebugJavaWithJavac'.
> javax.annotation.processing.FilerException: Attempt to recreate a file for type app.bacecek.defaultassistant.UserDao_Impl

This build fail is not reproducing without napt plugin.

Simple example is here: https://github.com/bacecek/sample-checking-assistant-role/tree/room_FilerException.

Environment:
Napt version 1.17, JDK 11, Gradle 7.5.1, Android Gradle Plugin 7.2.1, Room 2.4.3.

I'n not sure that the main cause of this problem is this plugin so it would be great if you will help me to investigate what is the main cause and maybe to fill the issue in Google's issue tracker.

[bacecek]

I'm seeing that during incremental compilation before starting annotation processing URLClassLoader.getURLs() contains not only compiled kotlin classes, but also previous compiled java classes:

ClassLoader.getURLs: [file:/Users/bacecek/work/sample-checking-assistant-role/app/build/tmp/kotlin-classes/debug/, file:/Users/bacecek/work/sample-checking-assistant-role/app/build/intermediates/javac/debug/classes/]

And @Dao annotation has CLASS retention, so that annotation processor is trying to process UserDao class twice: as java source and as class file.

From my perspective, we can try to not add classes to Arguments.instance(context).getClassNames() that already exists in Arguments.instance(context).getFileObjects(). What do you think?

UPD: This is not so easy as I expected. Maybe you have any ideas how to fix it?

[sergei-lapin]

Hey, @bacecek! Seems like targeting KotlinCompile destinationDirectory directly does the trick and fixes this incremental scenario.

[sergei-lapin]

I'll prepare new release shortly

[bacecek]

Great, thank you! Now it works