Unresolved reference for Dagger 2 in Kotlin

Question

I am trying to use a Dagger 2 in my Android project where I code in Kotlin. I took an example from Dagger 2 repo android-simple. I have managed to properly configure the project in Android Studio using an example from dagger-android-gradle-sample, it contains properly configured gradle files.

Now I started changing java classes to kotlin. This is how auto-converted DemoApplication.java looks like in kotlin:

public class DemoApplication : Application() {

    Singleton
    Component(modules = array(javaClass<AndroidModule>()))
    trait ApplicationComponent {
        public fun inject(application: DemoApplication)
        public fun inject(homeActivity: HomeActivity)
        public fun inject(demoActivity: DemoActivity)
    }

    public var component: ApplicationComponent? = null

    override fun onCreate() {
        super.onCreate()
        component = `Dagger_DemoApplication$ApplicationComponent`.builder().androidModule(AndroidModule(this)).build()
        component!!.inject(this)
    }
}

Dagger generated classes are visible in Kotlin but it complains about ($) sign used in the class name. ($) in Kotlin has special purpose so I guess that's why. You can note that auto-convertion wrapped the class name with (`) sign so editor does not complains about it. Unfortunately, compiler is failing with:

Error:(32, 21) Unresolved reference: `Dagger_DemoApplication$ApplicationComponent`

:app:compileDebugKotlin FAILED

There is also an exception if I try to build it from Terminal:

org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:compileDebugKotlin'.
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:69)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:46)
        at org.gradle.api.internal.tasks.execution.PostExecutionAnalysisTaskExecuter.execute(PostExecutionAnalysisTaskExecuter.java:35)
        at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:64)
        at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:58)
        at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:42)
        at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:52)
        at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:53)
        at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
        at org.gradle.api.internal.AbstractTask.executeWithoutThrowingTaskFailure(AbstractTask.java:305)
        at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.executeTask(AbstractTaskPlanExecutor.java:79)
        at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.processTask(AbstractTaskPlanExecutor.java:63)
        at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.run(AbstractTaskPlanExecutor.java:51)
        at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor.process(DefaultTaskPlanExecutor.java:23)
        at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter.execute(DefaultTaskGraphExecuter.java:88)
        at org.gradle.execution.SelectedTaskExecutionAction.execute(SelectedTaskExecutionAction.java:29)
        at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:62)
        at org.gradle.execution.DefaultBuildExecuter.access$200(DefaultBuildExecuter.java:23)
        at org.gradle.execution.DefaultBuildExecuter$2.proceed(DefaultBuildExecuter.java:68)
        at org.gradle.execution.DryRunBuildExecutionAction.execute(DryRunBuildExecutionAction.java:32)
        at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:62)
        at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:55)
        at org.gradle.initialization.DefaultGradleLauncher.doBuildStages(DefaultGradleLauncher.java:149)
        at org.gradle.initialization.DefaultGradleLauncher.doBuild(DefaultGradleLauncher.java:106)
        at org.gradle.initialization.DefaultGradleLauncher.run(DefaultGradleLauncher.java:86)
        at org.gradle.launcher.exec.InProcessBuildActionExecuter$DefaultBuildController.run(InProcessBuildActionExecuter.java:80)
        at org.gradle.launcher.cli.ExecuteBuildAction.run(ExecuteBuildAction.java:33)
        at org.gradle.launcher.cli.ExecuteBuildAction.run(ExecuteBuildAction.java:24)
        at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:36)
        at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:26)
        at org.gradle.launcher.cli.RunBuildAction.run(RunBuildAction.java:51)
        at org.gradle.internal.Actions$RunnableActionAdapter.execute(Actions.java:171)
        at org.gradle.launcher.cli.CommandLineActionFactory$ParseAndBuildAction.execute(CommandLineActionFactory.java:237)
        at org.gradle.launcher.cli.CommandLineActionFactory$ParseAndBuildAction.execute(CommandLineActionFactory.java:210)
        at org.gradle.launcher.cli.JavaRuntimeValidationAction.execute(JavaRuntimeValidationAction.java:35)
        at org.gradle.launcher.cli.JavaRuntimeValidationAction.execute(JavaRuntimeValidationAction.java:24)
        at org.gradle.launcher.cli.CommandLineActionFactory$WithLogging.execute(CommandLineActionFactory.java:206)
        at org.gradle.launcher.cli.CommandLineActionFactory$WithLogging.execute(CommandLineActionFactory.java:169)
        at org.gradle.launcher.cli.ExceptionReportingAction.execute(ExceptionReportingAction.java:33)
        at org.gradle.launcher.cli.ExceptionReportingAction.execute(ExceptionReportingAction.java:22)
        at org.gradle.launcher.Main.doAction(Main.java:33)
        at org.gradle.launcher.bootstrap.EntryPoint.run(EntryPoint.java:45)
        at org.gradle.launcher.bootstrap.ProcessBootstrap.runNoExit(ProcessBootstrap.java:54)
        at org.gradle.launcher.bootstrap.ProcessBootstrap.run(ProcessBootstrap.java:35)
        at org.gradle.launcher.GradleMain.main(GradleMain.java:23)
        at org.gradle.wrapper.BootstrapMainStarter.start(BootstrapMainStarter.java:33)
        at org.gradle.wrapper.WrapperExecutor.execute(WrapperExecutor.java:130)
        at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:48)
Caused by: org.gradle.api.GradleException: Compilation error. See log for more details
        at org.jetbrains.kotlin.gradle.tasks.KotlinCompile.compile(Tasks.kt:130)
        at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:63)
        at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.doExecute(AnnotationProcessingTaskFactory.java:218)
        at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.execute(AnnotationProcessingTaskFactory.java:211)
        at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.execute(AnnotationProcessingTaskFactory.java:200)
        at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:579)
        at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:562)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:80)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:61)
        ... 47 more

Does anyone know how to solve this problem? If not I will have to keep classes using Dagger_* in java.

Answer 1

You can solve it by waiting! See https://github.com/google/dagger/issues/58.

The $ symbol is being removed from all of the generated code before the first release (and hopefully sooner rather than later).

Additionally, I would file a bug with Jetbrains about the behavior since $ is a perfectly valid character to appear in a class name.