protected ActivationFile.Builder transformActivationFile_Missing(
                    Supplier<? extends ActivationFile.Builder> creator,
                    ActivationFile.Builder builder,
                    ActivationFile target) {
                String path = target.getMissing();
                String xformed = transformPath(path, target, "missing");

            //
            // idea:idea
            //
            String prefix = tok[0];

            if (numTokens == 2) {
                goal = tok[1];
            } else {
                // goal was missing - pass through to MojoNotFoundException
                goal = "";
            }

            // This is the case where someone has executed a single goal from the command line
            // of the form:

                PrintStream ps = new PrintStream(os);
                ps.println("Unable to load the mojo '" + mojoDescriptor.getGoal() + "' in the plugin '"
                        + pluginDescriptor.getId() + "'. A required class is missing: "
                        + cause.getMessage());
                pluginRealm.display(ps);

                throw new PluginContainerException(mojoDescriptor, pluginRealm, os.toString(), cause);

        assertThrows(
                ProjectBuildingException.class,
                () -> buildPom("artifact-id-inheritance/child"),
                "Missing artifactId did not cause validation error");
    }

    private void assertPathSuffixEquals(String expected, Object actual) {
        String a = actual.toString();

                        .exists(settingsFile.getExists())
                        .missing(settingsFile.getMissing())
                        .location("exists", toLocation(settingsFile.getLocation("exists")))
                        .location("missing", toLocation(settingsFile.getLocation("missing")))
                        .build());
            }

                scenario("Selected optional project")
                        .activeOptionalProjects(MODULE_B)
                        .expectResult(MODULE_B),
                scenario("Selected missing optional project")
                        .activeOptionalProjects("non-existing-module")
                        .expectResult(
                                PARENT_MODULE,
                                MODULE_C,

            ByteArrayOutputStream os = new ByteArrayOutputStream(1024);
            PrintStream ps = new PrintStream(os);
            ps.println(
                    "A required class was missing while executing " + mojoDescriptor.getId() + ": " + e.getMessage());
            pluginRealm.display(ps);
            Exception wrapper = new PluginContainerException(mojoDescriptor, pluginRealm, os.toString(), e);

import org.apache.maven.api.services.ModelBuilderRequest;
import org.apache.maven.api.services.ModelProblemCollector;

/**
 * Checks the model for missing or invalid values.
 *
 */
public interface ModelValidator {
    /**
     * Checks the specified file model for missing or invalid values. This model is directly created from the POM
     * file and has not been subjected to inheritance, interpolation or profile/default injection.

        assertContains(problems.messages.get(0), "'mirrors.mirror.id' must not be 'local'");
        assertContains(problems.messages.get(1), "'mirrors.mirror.url' for local is missing");
        assertContains(problems.messages.get(2), "'mirrors.mirror.mirrorOf' for local is missing");
        assertContains(problems.messages.get(3), "'mirrors.mirror.id' must not contain any of these characters");
    }

    @Test

    void testRoundTripProfiles() {
        Random entropy = new Random();
        ActivationFile af = ActivationFile.newBuilder()
                .exists("exists" + Long.toHexString(entropy.nextLong()))
                .missing("missing" + Long.toHexString(entropy.nextLong()))
                .build();
        ActivationProperty ap = ActivationProperty.newBuilder()
                .name("name" + Long.toHexString(entropy.nextLong()))