/**
 * Evaluator for plugin parameters expressions. Content surrounded by <code>${</code> and <code>}</code> is evaluated.
 * Recognized values are:
 * <table border="1">
 * <caption>Expression matrix</caption>
 * <tr><th>expression</th>                     <th></th>               <th>evaluation result</th></tr>

    final Map<Path, Holder> modelByPath = new ConcurrentHashMap<>();

    final Map<GAKey, Holder> modelByGA = new ConcurrentHashMap<>();

    public static class Holder {
        private volatile boolean set;
        private volatile Model model;

        Holder() {}

        Holder(Model model) {
            this.model = Objects.requireNonNull(model);

                Model model = findRawModel(from, gId, aId);
                if (model != null) {
                    context.modelByGA.put(new GAKey(gId, aId), new Holder(model));
                    context.modelByPath.put(model.getPomFile(), new Holder(model));
                }
                return model;
            }

            @Override
            public Model getRawModel(Path from, Path path) {

            ALIASES.put("cr", "rc");
        }

        /**
         * A comparable value for the empty-string qualifier. This one is used to determine if a given qualifier makes
         * the version older than one without a qualifier, or more recent.
         */
        private static final String RELEASE_VERSION_INDEX = String.valueOf(QUALIFIERS.indexOf(""));

        private final String value;

/**
 * Evaluator for plugin parameters expressions. Content surrounded by <code>${</code> and <code>}</code> is evaluated.
 * Recognized values are:
 * <table border="1">
 * <caption>Expression matrix</caption>
 * <tr><th>expression</th>                     <th></th>               <th>evaluation result</th></tr>
 * <tr><td><code>session.*</code></td>         <td></td>               <td></td></tr>

    }

    protected DefaultModelRepositoryHolder(DefaultModelRepositoryHolder holder) {
        this.session = holder.session;
        this.repositoryMerging = holder.repositoryMerging;
        this.pomRepositories = List.copyOf(holder.pomRepositories);
        this.externalRepositories = List.copyOf(holder.externalRepositories);
        this.repositories = List.copyOf(holder.repositories);
    }

    @Override

     *
     * @param session The session to use to resolve the model, must not be {@code null}.
     * @param parent The parent coordinates to resolve, must not be {@code null}.
     * @param modified a holder for the updated parent, must not be {@code null}.
     * @return The source of the requested POM, never {@code null}.
     * @throws ModelResolverException If the POM could not be resolved from any configured repository.
     */

            if (null == value && implType.isInterface() && configuration.getChildCount() == 0) {
                return null; // nothing to process
            }
            final Object bean = instantiateObject(implType);
            if (null == value) {
                processConfiguration(lookup, bean, loader, configuration, evaluator, listener);
            } else {

                ProjectBuildingException.class, () -> getProject(f1), "Expected to fail for past versions");
        assertThat(e.getMessage(), containsString("Building this project requires an older version of Maven"));
    }

    @Test
    void testFutureSchemaModelVersion() throws Exception {
        File f1 = getTestFile("src/test/resources/projects/future-schema-model-version-pom.xml");

                    Version.V20,
                    "modelVersion",
                    null,
                    "of '" + string + "' is older than the versions supported by this version of Maven: "
                            + validVersions + ". Building this project requires an older version of Maven.",
                    tracker);

        } else {
            addViolation(
                    problems,