// No project, but most certainly a dependency which has been built previously
        File packagedArtifactFile = findInProjectLocalRepository(artifact);
        if (packagedArtifactFile != null && packagedArtifactFile.exists()) {
            return packagedArtifactFile;
        }

        return null;
    }

    public List<String> findVersions(Artifact artifact) {
        List<String> versions = getProjects()

            protected ActivationFile.Builder transformActivationFile_Exists(
                    Supplier<? extends ActivationFile.Builder> creator,
                    ActivationFile.Builder builder,
                    ActivationFile target) {
                final String path = target.getExists();
                final String xformed = transformPath(path, target, "exists");

        Map.Entry<Artifact, Path> res = session.resolveArtifact(coord);
        assertNotNull(res);
        assertNotNull(res.getValue());
        assertTrue(Files.exists(res.getValue()));

        Node node = session.collectDependencies(session.createDependencyCoordinate(coord));
        assertNotNull(node);
        assertEquals(8, node.getChildren().size());
    }

     */
    @Nonnull
    Optional<Path> getArtifactPath(@Nonnull Artifact artifact);

    /**
     * Gets the relative path for a locally installed artifact. Note that the artifact need not actually exist yet at
     * the returned location, the path merely indicates where the artifact would eventually be stored.
     * <p>
     * Shortcut for {@code getService(LocalArtifactManager.class).getPathForLocalArtitact(...)}.
     *

        // System scoped version which should
        //
        d.setScope(Artifact.SCOPE_SYSTEM);
        File file = new File(getBasedir(), "src/test/repository-system/maven-core-2.1.0.jar");
        assertTrue(file.exists());
        d.setSystemPath(file.getCanonicalPath());

        artifact = repositorySystem.createDependencyArtifact(d);

        //

    public boolean isMerged() {
        return merged;
    }

    protected abstract void merge(Metadata recessive);

    static Metadata read(Path metadataPath) throws RepositoryException {
        if (!Files.exists(metadataPath)) {
            return Metadata.newInstance();
        }

        try (InputStream input = Files.newInputStream(metadataPath)) {
            return new MetadataStaxReader().read(input, false);

                        ModelProblem problem = new org.apache.maven.internal.impl.model.DefaultModelProblem(
                                "Child module " + moduleFile + " of " + pomFile + " does not exist",
                                ModelProblem.Severity.ERROR,
                                ModelProblem.Version.BASE,
                                model,
                                -1,

        @Override
        protected ActivationFile.Builder transformActivationFile_Exists(
                Supplier<? extends ActivationFile.Builder> creator,
                ActivationFile.Builder builder,
                ActivationFile target) {
            stk.push(nextFrame("exists"));
            try {
                return super.transformActivationFile_Exists(creator, builder, target);
            } finally {
                stk.pop();

        requireNonNull(source, "source is null");
        requireNonNull(relativeTarget, "relativeTarget is null");
        if (Files.isRegularFile(source)) {
            throw new IllegalArgumentException("source file does not exist or is not a file");
        }
        if (relativeTarget.isAbsolute()) {
            throw new IllegalArgumentException("Supplied URI is not relative");
        }
        URI target = baseURI.resolve(relativeTarget);