findOptionalProjectBySelector(projects, baseDirectory, selector);
            if (!optSelectedProject.isPresent()) {
                String message = "Could not find the selected project in the reactor: " + selector;
                throw new MavenExecutionException(message, request.getPom());
            }

            MavenProject selectedProject = optSelectedProject.get();

    public void sessionStarted(ExecutionEvent event) {
        if (logger.isInfoEnabled() && event.getSession().getProjects().size() > 1) {
            init();
            infoLine('-');

            infoMain("Reactor Build Order:");

            logger.info("");

            final List<MavenProject> projects = event.getSession().getProjects();
            for (MavenProject project : projects) {

                if (reactorContext.getReactorBuildStatus().isHalted()) {
                    break;
                }

                // MNG-6170: Only schedule other modules from reactor if we have more modules to build than one.
                if (analyzer.getNumberOfBuilds() > 1) {
                    final List<MavenProject> newItemsThatCanBeBuilt =

import org.apache.maven.project.DuplicateProjectException;
import org.apache.maven.project.MavenProject;
import org.apache.maven.project.ProjectSorter;

/**
 * Describes the interdependencies between projects in the reactor.
 *
 */
public class DefaultProjectDependencyGraph implements ProjectDependencyGraph {

    private final ProjectSorter sorter;

    private final List<MavenProject> allProjects;

                + artifact.getScope() + " wins)");

        // TODO better way than static? this might hide messages in a reactor
        if (!ignoredArtifacts.contains(artifact)) {
            logger.warn("\n\tArtifact " + artifact + " retains local artifactScope '" + artifact.getScope()

     * @return an {@link Optional} containing the project name to resume from, or empty if not specified
     */
    @Nonnull
    Optional<String> resumeFrom();

    /**
     * Returns the list of specified reactor projects to build instead of all projects.
     *
     * @return an {@link Optional} containing the list of project names to build, or empty if not specified
     */
    @Nonnull
    Optional<List<String>> projects();

                }
            }
        }
        return null;
    }

    private boolean isSafelyCacheable(RepositorySystemSession session, Artifact artifact) {
        /*
         * The workspace/reactor is in flux so we better not assume definitive information for any of its
         * artifacts/projects.
         */

        WorkspaceReader workspace = session.getWorkspaceReader();
        if (workspace == null) {

                throw new ArtifactDescriptorException(result);
            }

            Model model;

            // TODO hack: don't rebuild model if it was already loaded during reactor resolution
            final WorkspaceReader workspace = session.getWorkspaceReader();
            if (workspace instanceof MavenWorkspaceReader mavenWorkspaceReader) {

    /**
     * The full set of projects before any potential constraining by --projects. Useful in the case where you want to
     * build a smaller set of projects but perform other operations in the context of your reactor.
     */
    private List<MavenProject> allProjects;

    private MavenProject topLevelProject;

    private ProjectDependencyGraph projectDependencyGraph;

    private boolean parallel;

    /**

                String msg = str + " aggregator mojo is already being executed "
                        + "in this parallel build, those kind of mojos require exclusive access to "
                        + "reactor to prevent race conditions. This mojo execution will be blocked "
                        + "until the aggregator mojo is done.";
                warn(msg);
                acquiredAggregatorLock.lock();
            }