KSP Processor for Toothpick

Background

Toothpick is a Dependency Injection library for Java & Kotlin.

An important part of Toothpick is its ability to generate code at compile-time to avoid doing expensive reflection at runtime. This is handled by an annotation processor, which uses Java's apt and Kotlin's kapt APIs.

Google has since released an alternative, more modern annotation processor, built for Kotlin and compatible with Java projects: KSP (Kotlin Symbol Processor). It brings faster processing times than kapt on Kotlin projects. kapt has now been put in maintenance mode, and will not receive new features; it's recommended to migrate to KSP.

Goals

This projects aims to reimplement Toothpick's annotation processor with Kotlin-based technologies. It now uses KSP for better build performance, and generates Kotlin code for improved type safety.

Important note: This processor is mostly a drop-in replacement for the official kapt processor, but source compatibility was not a main goal. You might need to make small changes to your code when migrating from apt/kapt to KSP.

This is in part because of fundamental differences in the way KSP models Kotlin code compared to kapt, and in part because of the differences in generated Kotlin code vs. Java code ( no package visibility modifier, for example.)

Setup

plugins {
    // Remove this if you don't have any kapt(...) processors left in your dependencies:
    // kotlin("kapt") version "..."

    // Use the version that matches your Kotlin version!
    id("com.google.devtools.ksp") version "1.7.22-1.0.8"
}

repositories {
    mavenCentral()
    maven { url = uri("https://jitpack.io") }
}

dependencies {
    // Remove this:
    // kapt("com.github.stephanenicolas.toothpick:toothpick-compiler:...")

    // Replace the version number with the latest GitHub release
    ksp("com.github.bedrockstreaming.toothpick-ksp:compiler:<latest-version>")
}

ksp {
    // If you need to, specify some extra options.
    // See ToothpickOptions.kt for documentation.
    arg("option1", "value1")
    arg("option2", "value2")
    // ...
}