* @param session the {@link MavenSession}.
     */
    private void validateOptionalProjects(MavenExecutionRequest request, MavenSession session) {
        final ProjectActivation projectActivation = request.getProjectActivation();
        final Set<String> allOptionalSelectors = new HashSet<>();
        allOptionalSelectors.addAll(projectActivation.getOptionalActiveProjectSelectors());

        }
        enableOnPresentOption(
                commandLine, CLIManager.IGNORE_TRANSITIVE_REPOSITORIES, request::setIgnoreTransitiveRepositories);

        performProjectActivation(commandLine, request.getProjectActivation());
        performProfileActivation(commandLine, request.getProfileActivation());

        final String localRepositoryPath = determineLocalRepositoryPath(request);
        if (localRepositoryPath != null) {