Can I use Anvil?

This tool assists with partial replacement of Kapt+Dagger with Anvil in multi-module projects.

Background

Kapt+Dagger build performance in large projects is miserable.

Anvil is a Kotlin compiler plugin more performant than the Kapt+Dagger combo.

A subset of Kapt+Dagger functionality can be directly replaced with Anvil's factory generation without changing the ABI of generated code.

So can I use Anvil?

This Gradle plugin will tell you if you can replace Dagger+Kapt with Anvil in a mixed Java/Kotlin project.

Under the hood, it registers a Kapt annotation processor which detects the following patterns incompatible with Anvil.

• Java (non-Kotlin) @Modules.
• Java (non-Kotlin) @Singletons.
• Java classes with @Inject members.
• Kotlin classes with @Inject members inherited from a Java superclass.
• All @Components; components require Dagger anyway.
• Android-specific @ContributesAndroidInjector.

How to use it

Apply the plugin to the root project.

plugins {
    id("com.toasttab.can-i-use-anvil") version "<< version >>"
}

Run ./gradlew anvilMigrationReport to generate an aggregated report for all subprojects under build/anvil-aggregated-report.json.

The plugin needs to be aware of the main Kapt task in each subproject. This can be controlled via the anvilMigration extension. The default is kaptKotlin. However, in Android projects, Kapt tasks are variant-specific, e.g. kaptDebugKotlin.

anvilMigration {
    // for mixed Android/Java projects
    kaptTasks = listOf("kaptKotlin", "kaptDebugKotlin") 
}

References

• https://speakerdeck.com/zacsweers/improve-build-times-in-less-time?slide=67
• https://github.com/square/anvil#dagger-factory-generation