projects.add(project1);
        MavenProject project2 = createProject("groupId", "artifactId2", "1.0");
        projects.add(project2);
        project1.getDependencies().add(createDependency(project2));

        projects = new ProjectSorter(projects).getSortedProjects();

        assertEquals(project2, projects.get(0));
        assertEquals(project1, projects.get(1));
    }

    @Test

            throws DuplicateProjectException {
        Map<String, MavenProject> index = new LinkedHashMap<>();
        Map<String, List<File>> collisions = new LinkedHashMap<>();

        for (MavenProject project : projects) {
            String projectId = ArtifactUtils.key(project.getGroupId(), project.getArtifactId(), project.getVersion());

    private final Map<String, MavenProject> projects;

    private final Map<String, Integer> indices;

    public ProjectIndex(List<MavenProject> projects) {
        this.projects = new HashMap<>(projects.size() * 2);
        this.indices = new HashMap<>(projects.size() * 2);

        for (int i = 0; i < projects.size(); i++) {
            MavenProject project = projects.get(i);

        this(projects, projects);
    }

    /**
     * Creates a new project dependency graph based on the specified projects.
     *
     * @param allProjects All collected projects.
     * @param projects    The projects to create the dependency graph with.
     * @throws DuplicateProjectException
     * @throws CycleDetectedException
     * @since 3.5.0

        for (MavenProject project : projects) {
            request.setArtifact(new ProjectArtifact(project));
            request.setArtifactDependencies(project.getDependencyArtifacts());
            request.setManagedVersionMap(project.getManagedVersionMap());
            request.setRemoteRepositories(project.getRemoteArtifactRepositories());

    public void setProjects(List<MavenProject> projects) {
        if (!projects.isEmpty()) {
            MavenProject first = projects.get(0);
            this.currentProject = ThreadLocal.withInitial(() -> first);
            this.topLevelProject = projects.stream()
                    .filter(project -> project.isExecutionRoot())
                    .findFirst()
                    .orElse(first);

        activeProjectSelectors.forEach(this::activateOptionalProject);
    }

    /**
     * Overwrites the inactive projects based on a pre-Maven 4 "inactive projects" list.
     * @param inactiveProjectSelectors A {@link List} of project selectors that must be deactivated.
     * @deprecated Use {@link #deactivateOptionalProject(String)} or {@link #deactivateRequiredProject(String)} instead.
     */
    @Deprecated

import org.apache.maven.project.CycleDetectedException;
import org.apache.maven.project.DuplicateProjectException;
import org.apache.maven.project.MavenProject;
import org.apache.maven.project.ProjectBuildingException;
import org.apache.maven.project.collector.MultiModuleCollectionStrategy;
import org.apache.maven.project.collector.PomlessCollectionStrategy;
import org.apache.maven.project.collector.RequestPomCollectionStrategy;

     * is a prerequisite of the given project.
     *
     * @param project The project whose upstream projects should be retrieved, must not be {@code null}.
     * @param transitive A flag whether to retrieve all direct and indirect upstream projects or just the immediate
     *            upstream projects.

            return new ArrayList<>();
        }
    }

    private Optional<MavenProject> findOptionalProjectBySelector(
            List<MavenProject> projects, File reactorDirectory, String selector) {
        return projects.stream()
                .filter(project -> isMatchingProject(project, selector, reactorDirectory))
                .findFirst();
    }

    File getBaseDirectoryFromRequest(MavenExecutionRequest request) {