I am making an annotation processor that generates Kotlin source files using Kotlin poet, however I am unsure how can I make incremental processing work properly. The problem is that outdated source files don't get deleted. How can I "mark" generated Kotlin source file as being outdated and that they need to be deleted? Example:

@NbtSerializable
class Foo // --> Generates source file named "FooUtil"

Now I remove

@NbtSerializable

and need

FooUtil

to be deleted as well.

You need to call

addOriginatingElement

on every TypeSpec/FunSpec/etc. builder and pass the corresponding element. Also make sure you use only

FileSpec.writeTo(Filer)

for writing files.