@HiltAndroidApp base class must extend Application error after update to Dagger Hilt 2.42

When update hilt version 2.41 to 2.42 fails build with error message.

~/g/g/s/dagger-2.42-libapplication ❯❯❯ ./gradlew installDebug
Configuration on demand is an incubating feature.

> Task :app:hiltJavaCompileDebug FAILED
error: [Hilt]
  @HiltAndroidApp base class must extend Application. Found: com.example.mylibrary.Hilt_MyApplication
  [Hilt] Processing did not complete. See error above for details.
1 error

FAILURE: Build failed with an exception.

This project has Application class into library module (not application module).

// success 2.41, but failed 2.42

// define into library module
@HiltAndroidApp
class MyApplication : Application()

If This Application class move to application module, the build will succeed.

// application module
@HiltAndroidApp
class MyApplication : Application()

it’s expected behavior on 2.42?

---

sample project: https://github.com/satoshun-android-example/dagger-2.42-libapplication

[bcorso]

Hi @satoshun, Thanks for reporting this.

You’re right that the Hilt application class must be located in the Gradle application module when you’re using the Hilt Gradle plugin.

As for why your build started failing when upgrading to 2.42, I’m not sure. However, due to the mechanics of the Hilt Gradle plugin it’s not something that we can really guarantee will work except at the Gradle application module level, so you should definitely move it.

I’ll update the documentation to make this explicit.

We can also look into automating this check so that it will automatically detect and fail when the application class is not defined in the Gradle application module.

[kuanyingchou]

A more explicit error message will be included in the next release when an Application annotated with @HiltAndroidApp is not defined in an application module. Closing this one.