@Inject
    private SessionScope sessionScope;

    protected String component() {
        return "deployer";
    }

    @Test
    void testArtifactInstallation() throws Exception {
        sessionScope.enter();
        try {
            sessionScope.seed(MavenSession.class, mock(MavenSession.class));

            String artifactBasedir = new File(getBasedir(), "src/test/resources/artifact-install").getAbsolutePath();

        assertNotNull(bean.myBean);
        assertNotSame(bean.myBean.getClass(), MySessionScopedBean.class);

        assertThrows(OutOfScopeException.class, () -> bean.myBean.getSession());

        sessionScope.enter();
        sessionScope.seed(Session.class, this.session);
        assertNotNull(bean.myBean.getSession());
        assertNotNull(bean.myBean.getAnotherBean());

public abstract class AbstractNode implements Node {

    abstract org.eclipse.aether.graph.DependencyNode getDependencyNode();

    @Override
    public boolean accept(NodeVisitor visitor) {
        if (visitor.enter(this)) {
            for (Node child : getChildren()) {
                if (!child.accept(visitor)) {
                    break;
                }
            }
        }
        return visitor.leave(this);
    }

    @Test
    void testNestedEnter() throws Exception {
        MojoExecutionScope scope = new MojoExecutionScope();

        scope.enter();

        Object o1 = new Object();
        scope.seed(Object.class, o1);
        assertSame(o1, scope.scope(Key.get(Object.class), null).get());

        scope.enter();
        Object o2 = new Object();
        scope.seed(Object.class, o2);

     * @return <code>true</code> to visit the specified dependency node's children, <code>false</code> to skip the
     *         specified dependency node's children and proceed to its next sibling
     */
    boolean enter(@Nonnull Node node);

    /**
     * Ends the visit to the specified dependency node.
     *
     * @param node the dependency node to visit

        private final Map<Key<?>, Object> provided = new HashMap<>();
    }

    private final ThreadLocal<LinkedList<ScopeState>> values = new ThreadLocal<>();

    public MojoExecutionScope() {}

    public void enter() {
        LinkedList<ScopeState> stack = values.get();
        if (stack == null) {
            stack = new LinkedList<>();
            values.set(stack);
        }
        stack.addFirst(new ScopeState());
    }

        public Collection<CachingProvider<?>> providers() {
            return provided.values();
        }
    }

    private final List<ScopeState> values = new CopyOnWriteArrayList<>();

    public void enter() {
        values.add(0, new ScopeState());
    }

    protected ScopeState getScopeState() {
        if (values.isEmpty()) {

public abstract class AbstractNode implements Node {

    abstract org.eclipse.aether.graph.DependencyNode getDependencyNode();

    @Override
    public boolean accept(NodeVisitor visitor) {
        if (visitor.enter(this)) {
            for (Node child : getChildren()) {
                if (!child.accept(visitor)) {
                    break;
                }
            }
        }
        return visitor.leave(this);
    }

    @Inject
    private SessionScope sessionScope;

    protected String component() {
        return "installer";
    }

    @Test
    void testArtifactInstallation() throws Exception {
        sessionScope.enter();
        try {
            sessionScope.seed(MavenSession.class, mock(MavenSession.class));

            String artifactBasedir = new File(getBasedir(), "src/test/resources/artifact-install").getAbsolutePath();