what are the differences between `kapt` and `kaptK...

# kapt

[Michal Klimczak]

what are the differences between kapt and kaptKotlin directories in generated/source? When should I use one or the other? Can't really find anything about it. Dagger and moshi seem to generate to kapt.

From my tests it seems that I need to manually tell gradle where to look for these files for either of these (via kotlin.srcDir("${buildDir.absolutePath}/generated/source/kapt/") or kotlin.srcDir("${buildDir.absolutePath}/generated/source/kaptKotlin/") . Yet it doesn't seem to be necessary for dagger etc.

If that makes any difference, I'm asking about kotlin multiplatform module.

[Michal Klimczak]

The only difference I see is that kaptKotlin is not properly marked as generated sources root in my android studio, but that might be unrelated

[tddmonkey]

It’s been a while since I’ve written an annotation processor so take what I say with a grain of salt - but I believe that each processor either defines or makes configurable where any sources are output to. So the difference between the above is just that the processors output to different locations

[tddmonkey]

Ah - looks like my info is slightly out of date.

Kapt can generate Kotlin sources. Just write the generated Kotlin source files to the directory specified by processingEnv.options["kapt.kotlin.generated"], and these files will be compiled together with the main sources.

https://kotlinlang.org/docs/reference/kapt.html

[Michal Klimczak]

thank you for responding! I do exactly that and write the generated files to a file that I get from processingEnv.options["kapt.kotlin.generated"] but the client of my processor still needs to explicitly use kotlin.srcDir("${buildDir.absolutePath}/generated/source/kaptKotlin/") in his build.gradle.

On the other hand, moshi writes files to processingEnv.filer and they end up in /generated/source/kapt/, but they don't seem to require the kotlin.srcDir to be explicitly set. When I do the same thing, kotlin.srcDir("${buildDir.absolutePath}/generated/source/kapt/") is required. It's either a kotlin multiplatform thing or some kind of additional configuration that I cannot find.

[Michal Klimczak]

went to SO with that: https://stackoverflow.com/questions/66030192/kapt-in-kotlin-multiplatform-src-dirs-not-recognized-by-gradle-and-ide-by-defa

[tddmonkey]

tbf writing annotation processors does end up being a lot of trial and error as the docs aren’t brilliant