String rawChildModelVersion = childModel.getVersion();

                if (rawChildModelVersion == null) {
                    // Message below is checked for in the MNG-2199 core IT.
                    problems.add(
                            Severity.FATAL,
                            ModelProblem.Version.V31,
                            "Version must be a constant",

package org.apache.maven.project;

import org.apache.maven.artifact.Artifact;

/**
 * This exception is thrown if an application attempts to attach
 * two of the same artifacts to a single project.
 *
 * TODO Make this a checked exception, and modify the API of MavenProjectHelper.
 * Currently, this modification would create compatibility problems for existing plugins.
 */
public class DuplicateArtifactAttachmentException extends RuntimeException {

    /**
     * Returns a new tree starting at this node, filtering the children.
     * Note that this node will not be filtered and only the children
     * and its descendant will be checked.
     *
     * @param filter the filter to apply
     * @return a new filtered graph
     */
    @Nonnull
    Node filter(@Nonnull Predicate<Node> filter);

    /**

     * filters out currently built artifacts, as events are fired for them as well, but their resolved artifact
     * file would point to checked out source-tree, not the local repository.
     * <p>
     * Visible for testing.
     */
    static boolean isLocalRepositoryArtifactOrMissing(RepositorySystemSession session, Artifact artifact) {

                    && versionRangeResult.getVersionConstraint().getRange() != null
                    && versionRangeResult.getVersionConstraint().getRange().getUpperBound() == null) {
                // Message below is checked for in the MNG-2199 core IT.
                throw new UnresolvableModelException(
                        String.format(
                                "The requested parent version range '%s' does not specify an upper bound",

                            if (logger.isDebugEnabled()) {
                                // Message below is checked for in the MNG-2199 core IT.
                                logger.warn("Failed to build parent project for " + project.getId(), e);
                            } else {
                                // Message below is checked for in the MNG-2199 core IT.

     */
    RepositoryRequest setOffline(boolean offline);

    /**
     * Indicates whether remote repositories should be re-checked for updated artifacts/metadata regardless of their
     * configured update policy.
     *
     * @return {@code true} if remote repositories should be re-checked for updated artifacts/metadata, {@code false}
     *         otherwise.
     */
    boolean isForceUpdate();

    /**

 */
@FunctionalInterface
public interface MavenPluginPrerequisitesChecker extends Consumer<PluginDescriptor> {
    /**
     *
     * @param pluginDescriptor
     * @throws IllegalStateException in case the checked prerequisites are not met
     */
    void accept(PluginDescriptor pluginDescriptor);

                    toList(result.getArtifacts()),
                    result.getMissingArtifacts(),
                    request.getRemoteRepositories());
        }

        // this should never happen since we checked all possible error sources before but better be sure
        if (result.hasExceptions()) {
            throw new ArtifactResolutionException(

 *     <code>1.0alpha1 =&gt; [1, [alpha, 1]]</code></li>
 * <li>unlimited number of version components,</li>
 * <li>version components in the text can be digits or strings,</li>
 * <li>strings are checked for well-known qualifiers and the qualifier ordering is used for version ordering.
 *     Well-known qualifiers (case insensitive) are:<ul>
 *     <li><code>alpha</code> or <code>a</code></li>