* is meant for exclusive consumption by the model builder and is opaque to the cache implementation. The cache key is
 * formed by a combination of group id, artifact id, version and tag. The first three components generally refer to the
 * identity of a model. The tag allows for further classification of the associated data on the sole discretion of the
 * model builder.
 *
 */

 * is meant for exclusive consumption by the model builder and is opaque to the cache implementation. The cache key is
 * formed by a combination of group id, artifact id, version and tag. The first three components generally refer to the
 * identity of a model. The tag allows for further classification of the associated data on the sole discretion of the
 * model builder.
 *
 */

        <field>
          <name>artifactId</name>
          <version>3.0.0+</version>
          <required>true</required>
          <description>The identifier for this artifact that is unique within the group given by the
            group ID. An artifact is something that is either produced or used by a project.
            Examples of artifacts produced by Maven for a project include: JARs, source and binary

     *
     * @param model The POM to extract the plugin configuration from, may be {@code null}.
     * @param pluginGroupId The group id of the plugin whose configuration should be used, must not be {@code null} or
     *            empty.
     * @param pluginArtifactId The artifact id of the plugin whose configuration should be used, must not be

                if (matcher.matches()) {
                    Snapshot snapshot = new Snapshot();
                    snapshot.setTimestamp(matcher.group(2));
                    try {
                        snapshot.setBuildNumber(Integer.parseInt(matcher.group(3)));
                        artifact.addMetadata(new SnapshotArtifactRepositoryMetadata(artifact, snapshot));
                    } catch (NumberFormatException e) {

        ArtifactMetadataSource source = getContainer().lookup(ArtifactMetadataSource.class, "maven");
        ResolutionGroup group = source.retrieve(m, localRepository(), new ArrayList<>());
        List<ArtifactRepository> repositories = group.getResolutionRepositories();
        assertEquals(1, repositories.size(), "There should be one repository!");
        ArtifactRepository repository = repositories.get(0);

   | This is a list of additional group identifiers that will be searched when resolving plugins by their prefix, i.e.
   | when invoking a command line like "mvn prefix:goal". Maven will automatically add the group identifiers
   | "org.apache.maven.plugins" and "org.codehaus.mojo" if these are not already contained in the list.
   |-->
  <pluginGroups>
    <!-- pluginGroup
     | Specifies a further group identifier to use for plugin lookup.

    @Nonnull
    ArtifactCoordinate createArtifactCoordinate(@Nonnull String coordString);

    /**
     * Shortcut for {@code getService(ArtifactFactory.class).create(...)}.
     *
     * @param groupId the group identifier, or {@code null} is unspecified
     * @param artifactId the artifact identifier, or {@code null} is unspecified
     * @param version the artifact version, or {@code null} is unspecified

    }

    @Test
    void testPluginArtifactsExpressionReference() throws Exception {
        MojoExecution exec = newMojoExecution();

        Artifact depArtifact = createArtifact("group", "artifact", "1");

        List<Artifact> deps = new ArrayList<>();
        deps.add(depArtifact);

        exec.getMojoDescriptor().getPluginDescriptor().setArtifacts(deps);

                            BuilderProblem.Severity.ERROR,
                            "pluginGroups.pluginGroup[" + i + "]",
                            null,
                            "must denote a valid group id and match the pattern " + ID);
                }
            }
        }

        List<Server> servers = settings.getServers();

        if (servers != null) {