val extensionsMock = run {
                val myExtensionMock = mock<MyExtension>()
                val extensionsSchemaMock = mock<ExtensionsSchema> {
                    on { elements }.thenReturn(listOf<ExtensionSchema>(object : ExtensionSchema {
                        override fun getName(): String = "myExtension"
                        override fun getPublicType(): TypeOf<*> = TypeOf.typeOf(MyExtension::class.java)

 * The `@DeferredConfigurable` annotation has been removed.
 * The method `isDeferredConfigurable()` was removed from `ExtensionSchema`.
 * `IdeaPlugin.performPostEvaluationActions()` and `EclipsePlugin.performPostEvaluationActions()` have been removed.
 * `The `BroadcastingCollectionEventRegister.getAddAction()` method has been removed with no replacement.

import groovy.lang.Closure;
import org.gradle.api.Action;
import org.gradle.api.internal.plugins.DslObject;
import org.gradle.api.internal.plugins.ExtensionContainerInternal;
import org.gradle.api.plugins.ExtensionsSchema;
import org.gradle.api.plugins.ExtraPropertiesExtension;
import org.gradle.api.reflect.TypeOf;
import org.gradle.internal.Cast;
import org.gradle.internal.Describables;

}


private
fun getExtensionInfo(target: ExtensionAware): List<ExtensionInfo> {
    val annotationChecker = CachedHierarchyAnnotationChecker(Restricted::class)
    return target.extensions.extensionsSchema.elements.mapNotNull {
        val type = it.publicType.concreteClass.kotlin
        if (annotationChecker.isAnnotatedMaybeInSupertypes(type))

    fun collectSchemaOf(target: Any, targetType: TypeOf<*>) {
        if (target is ExtensionAware) {
            accessibleContainerSchema(target.extensions.extensionsSchema).forEach { schema ->
                extensions.add(ProjectSchemaEntry(targetType, schema.name, schema.publicType))
                collectSchemaOf(target.extensions.getByName(schema.name), schema.publicType)
            }