IssueTracker

I'm setting up a custom task that adds a generated Java source directory, but my approach (which may be entirely wrong, but this is the best I've got based on the documentation available) leads to a confusing error when a variant does not have Java sources (e.g. a KMP project variant).

    project.tasks
        .register(computeTaskName("compile", variant, "AidlApi"), StableAidlCompile::class.java) {
            // ...
        }
        .also { taskProvider ->
            variant.sources.java?.addGeneratedSourceDirectory( // <-- crash
                taskProvider,
                StableAidlCompile::sourceOutputDir
            )

This happens because variant.sources is a AnalyticsEnabledSources wrapping a Sources where the java property is null. When we attempt to create an analytics-enabled wrapper around that null value, we crash with:

Cause 1: org.gradle.api.reflect.ObjectInstantiationException: Could not create an instance of type com.android.build.api.component.analytics.AnalyticsEnabledFlat.
        at org.gradle.internal.instantiation.generator.DependencyInjectingInstantiator.doCreate(DependencyInjectingInstantiator.java:67)
        at org.gradle.internal.instantiation.generator.DependencyInjectingInstantiator.newInstance(DependencyInjectingInstantiator.java:53)
        at org.gradle.api.internal.model.DefaultObjectFactory.newInstance(DefaultObjectFactory.java:92)
        at com.android.build.api.component.analytics.AnalyticsEnabledSources.getJava(AnalyticsEnabledSources.kt:36)
        at com.android.build.api.component.analytics.AnalyticsEnabledSources_Decorated.getJava(Unknown Source)
        at androidx.stableaidl.StableAidlTasksKt.registerCompileAidlApi(StableAidlTasks.kt:96)

Which makes sense because the delegate parameter is null. See the AnalyticsEnabledFlat.kt class here.

I think what we probably need instead is a null check and a nullable return type here in AnalyticsEnabledSources:

    override val java: SourceDirectories.Flat
        get() {
            stats.variantApiAccessBuilder.addVariantPropertiesAccessBuilder().type =
                VariantPropertiesMethodType.SOURCES_JAVA_ACCESS_VALUE
            return objectFactory.newInstance(
                AnalyticsEnabledFlat::class.java,
                delegate.java,
                stats,
                objectFactory)
        }