usedTypes.clear();
            }
        }
    }

    @Override
    public Optional<Type> lookup(String id) {
        return Optional.of(require(id));
    }

    @Override
    @Nonnull
    public Type require(String id) {
        nonNull(id, "id");
        return usedTypes.computeIfAbsent(id, i -> {
            Type type = types.get(id);
            if (type == null) {

/**
 * Provides backwards compatibility with Maven 3.2.3 and earlier. Clients that do not require compatibility with Maven
 * 3.2.3 and earlier are encouraged to use {@link JavaToolchainImpl}.
 * <strong>Note:</strong> This is an internal component whose interface can change without prior notice.
 *
 * @deprecated clients that do not require compatibility with Maven 3.2.3 and earlier should link to
 *             {@link JavaToolchainImpl} instead.

        return getService(TypeRegistry.class).require(id);
    }

    @Override
    public Language requireLanguage(String id) {
        return getService(LanguageRegistry.class).require(id);
    }

    @Override
    public Packaging requirePackaging(String id) {
        return getService(PackagingRegistry.class).require(id);
    }

    @Override

        this.typeRegistry = requireNonNull(typeRegistry, "typeRegistry");
    }

    @Override
    public ArtifactType get(String typeId) {
        Type type = typeRegistry.require(typeId);
        if (type instanceof ArtifactType) {
            return (ArtifactType) type;
        }
        if (type != null) {
            return new DefaultType(
                    type.id(),

        return getService(TypeRegistry.class).require(id);
    }

    @Override
    public Language requireLanguage(String id) {
        return getService(LanguageRegistry.class).require(id);
    }

    @Override
    public Packaging requirePackaging(String id) {
        return getService(PackagingRegistry.class).require(id);
    }

    @Override

                        throw new IllegalStateException(e);
                    }
                }
            }
            throw new IllegalArgumentException("The use of session scoped proxies require "
                    + "a org.eclipse.sisu.Typed or javax.enterprise.inject.Typed annotation");
        }
    }

    /**
     * A provider wrapping an existing provider with a cache

import org.apache.maven.api.annotations.Nonnull;

public interface ExtensibleEnumRegistry<T extends ExtensibleEnum> extends Service {
    @Nonnull
    Optional<T> lookup(@Nonnull String id);

    @Nonnull
    default T require(@Nonnull String id) {
        return lookup(id).orElseThrow(() -> new IllegalArgumentException("Unknown extensible enum value '" + id + "'"));
    }

            }
        }
    }

    @Override
    public ArtifactHandler getArtifactHandler(String id) {
        return allHandlers.computeIfAbsent(id, k -> {
            Type type = typeRegistry.require(id);
            return new DefaultArtifactHandler(
                    id,
                    type.getExtension(),
                    type.getClassifier(),
                    null,
                    null,

     * anything useful.
     */
    @Test
    void testMojoThatRequiresExecutionToAGivenPhaseBeforeExecutingItself() throws Exception {}

    // test that mojo which does not require dependency resolution trigger no downloading of dependencies

    // test interpolation of basedir values in mojo configuration

    // test a build where projects use different versions of the same plugin

        // Here we will actually not have any artifacts because the ProjectDependenciesResolver is not involved here. So
        // right now it's not valid to ask for artifacts unless plugins require the artifacts.

        project.getCompileClasspathElements();
    }

    @Test
    void testBuildFromModelSource() throws Exception {