IssueTracker

AGP: 8.0.0-alpha10

Using the snippet below:

abstract class VersionFileWriterTask extends DefaultTask {
    @OutputFile
    abstract DirectoryProperty getOutputFile();

    @TaskAction
    void run() {
        getOutputFile().get().asFile.write("foo bar this is created")
    }
}

def writeVersionFile = tasks.register("writeVersionFile", VersionFileWriterTask.class)
androidComponents {
    onVariants(selector().all(),  { variant ->
        variant.sources.resources.addGeneratedSourceDirectory(writeVersionFile, VersionFileWriterTask::getOutputFile)
    })
}

and running ./gradlew :library:assembleDebug --configuration-cache fails with

Configuration cache state could not be cached: field `singleStorage` of `com.android.build.api.artifact.impl.TypedStorageProvider` bean found in field `directory` of `com.android.build.api.artifact.impl.StorageProviderImpl` bean found in field `storageProvider` of `com.android.build.api.artifact.impl.ArtifactsImpl` bean found in field `artifacts` of `com.android.build.gradle.internal.variant.TestVariantData` bean found in field `variantData` of `com.android.build.gradle.internal.api.TestVariantImpl` bean found in field `testVariant` of `com.android.build.gradle.internal.api.LibraryVariantImpl` bean found in field `androidVariant` of `org.jetbrains.kotlin.gradle.plugin.mpp.KotlinJvmAndroidCompilation` bean found in field `storage` of `org.gradle.internal.extensibility.DefaultExtraPropertiesExtension` bean found in field `extraProperties` of `com.android.build.gradle.internal.services.ProjectServices` bean found in field `projectServices` of `com.android.build.gradle.internal.services.VariantServicesImpl` bean found in field `receiver` of `com.android.build.api.variant.impl.FlatSourceDirectoriesImpl$getAsFileTrees$1$1$1` bean found in field `$fileTreeCreator` of `com.android.build.api.variant.impl.TaskProviderBasedDirectoryEntryImpl$asFileTree$1` bean found in field `transformer` of `org.gradle.api.internal.provider.TransformBackedProvider` bean found in field `provider` of `org.gradle.configurationcache.serialization.codecs.ProviderBackedFileCollectionSpec` bean found in field `mainSpec` of task `:mylibrary:processDebugJavaRes` of type `com.android.build.gradle.internal.tasks.ProcessJavaResTask`: error writing value of type 'java.util.LinkedHashMap'
> java.util.ConcurrentModificationException (no error message)

Adding to variant.sources.java instead of variant.sources.resources fixes the issue.