import org.gradle.plugin.use.PluginId;

import javax.annotation.Nullable;
import javax.annotation.concurrent.ThreadSafe;
import java.util.Optional;

@ThreadSafe
public interface PluginRegistry {
    <T> PluginImplementation<T> inspect(Class<T> clazz);

    /**
     * Extracts plugin information for the given class, if known to this registry.
     */
    @Nullable

        expect:
        def unqualified = pluginRegistry.lookup(DefaultPluginId.of("somePlugin"))
        unqualified.pluginId == DefaultPluginId.of("org.gradle.somePlugin")
        unqualified.displayName.displayName == "plugin 'org.gradle.somePlugin'"
        unqualified.asClass() == TestPlugin1

        def qualified = pluginRegistry.lookup(DefaultPluginId.of("org.gradle.somePlugin"))

    public static final PluginId NOOP_PLUGIN_ID = DefaultPluginId.of("noop");
    private final PluginRegistry pluginRegistry;

    public NoopPluginResolver(PluginRegistry pluginRegistry) {
        this.pluginRegistry = pluginRegistry;
    }

    @Override
    public PluginResolutionResult resolve(PluginRequestInternal pluginRequest) {
        if (pluginRequest.getId().equals(NOOP_PLUGIN_ID)) {

public class PluginResolverFactory {

    private final PluginRegistry pluginRegistry;
    private final DocumentationRegistry documentationRegistry;
    private final ClientInjectedClasspathPluginResolver injectedClasspathPluginResolver;
    private final List<PluginResolverContributor> pluginResolverContributors;

    public PluginResolverFactory(
        PluginRegistry pluginRegistry,
        DocumentationRegistry documentationRegistry,

    private final DocumentationRegistry documentationRegistry;
    private final PluginRegistry pluginRegistry;

    public CorePluginResolver(DocumentationRegistry documentationRegistry, PluginRegistry pluginRegistry) {
        this.documentationRegistry = documentationRegistry;
        this.pluginRegistry = pluginRegistry;
    }

    @Override
    public PluginResolutionResult resolve(PluginRequestInternal pluginRequest) {

import javax.annotation.Nullable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class DefaultPluginRequestApplicator implements PluginRequestApplicator {
    private final PluginRegistry pluginRegistry;
    private final PluginResolverFactory pluginResolverFactory;
    private final PluginArtifactRepositoriesProvider pluginRepositoriesProvider;
    private final PluginResolutionStrategyInternal pluginResolutionStrategy;

    private final PluginRegistry pluginRegistry;
    private final PluginManagerInternal pluginManager;

    public DefaultPluginContainer(PluginRegistry pluginRegistry, final PluginManagerInternal pluginManager, CollectionCallbackActionDecorator callbackActionDecorator) {
        super(Plugin.class, callbackActionDecorator);
        this.pluginRegistry = pluginRegistry;
        this.pluginManager = pluginManager;
    }

        void apply(Object target) {
        }
    }

    def docRegistry = new DocumentationRegistry()
    def pluginRegistry = Mock(PluginRegistry)
    def impl = Mock(PluginImplementation)
    def pluginManager = Mock(PluginManagerInternal)

    def resolver = new CorePluginResolver(docRegistry, pluginRegistry)

    PluginRequestInternal request(String id, String version = null) {

    private final ScriptClassPathResolver scriptClassPathResolver;
    private final ClassLoaderScope parentScope;
    private final PluginInspector pluginInspector;
    private final Lazy<PluginRegistry> pluginRegistry;

    public DefaultInjectedClasspathPluginResolver(
        ClassLoaderScope parentScope,
        ScriptClassPathResolver scriptClassPathResolver,
        FileCollectionFactory fileCollectionFactory,

    }

    private PluginResolutionResult resolveAlreadyOnClasspath(PluginId pluginId, @Nullable String pluginVersion) {
        DefaultPluginRegistry pluginRegistry = new DefaultPluginRegistry(pluginInspector, parentLoaderScope);
        PluginImplementation<?> plugin = pluginRegistry.lookup(pluginId);
        if (plugin != null) {
            PluginResolution pluginResolution = new ClassPathPluginResolution(pluginId, pluginVersion, plugin);