*/
        org.apache.maven.artifact.Artifact result = new org.apache.maven.artifact.DefaultArtifact(
                artifact.getGroupId(),
                artifact.getArtifactId(),
                artifact.getVersion(),
                null,
                artifact.getProperty(ArtifactProperties.TYPE, artifact.getExtension()),
                nullify(artifact.getClassifier()),
                handler);

                Plugin existing = plugins.get(plugin);
                if (existing != null) {
                    if (existing.getVersion() == null) {
                        existing.setVersion(plugin.getVersion());
                        existing.setLocation("version", location);
                    }
                    plugin = existing;
                } else {
                    plugins.put(plugin, plugin);

 *
 * @since 3.0
 */
public interface PluginVersionResult {

    /**
     * The resolved plugin version.
     *
     * @return The resolved plugin version, never {@code null}.
     */
    String getVersion();

    /**
     * The repository from which the plugin version was resolved.
     *
     * @return The repository from which the plugin version was resolved, never {@code null}.
     */

                CoreExtension conflict = selectedExtensions.putIfAbsent(key, coreExtension);
                if (conflict != null && !Objects.equals(coreExtension.getVersion(), conflict.getVersion())) {
                    conflicts.add(String.format(
                            "Conflicting extension %s: %s vs %s",
                            key,

        }

        // beware meta-versions!
        String version = metadata.getVersion();
        if (Artifact.LATEST_VERSION.equals(version) || Artifact.RELEASE_VERSION.equals(version)) {
            // meta-versions are not valid <version/> values...don't write them.
            metadata.setVersion(null);
        }

        if (changed || !metadataFile.exists()) {

     */
    public String getVersion() {
        return (version != null) ? version : "";
    }

    /**
     * Sets the effective version of the model.
     *
     * @param version The effective version of the model, may be {@code null}.
     */
    public void setVersion(String version) {
        this.version = version;
    }

    /**

                        || dependency.getArtifactId() == null
                        || dependency.getArtifactId().isEmpty()
                        || dependency.getVersion() == null
                        || dependency.getVersion().isEmpty()) {
                    // guard against case where best-effort resolution for invalid models is requested
                    continue;
                }

                .getOrDefault(artifact.getArtifactId(), Collections.emptyMap())
                .values()
                .stream()
                .map(MavenProject::getVersion)
                .collect(Collectors.collectingAndThen(Collectors.toList(), Collections::unmodifiableList));
        if (!versions.isEmpty()) {
            return versions;
        }
        return getAllProjects()

/**
 *
 *
 * @since 4.0.0
 */
@Experimental
@Immutable
public interface ArtifactFactoryRequest extends Request<Session> {

    String getGroupId();

    String getArtifactId();

    String getVersion();

    String getClassifier();

    String getExtension();

    String getType();

    static ArtifactFactoryRequest build(

                            main.getArtifactId(),
                            BUILD_POM_CLASSIFIER,
                            main.getExtension(),
                            main.getVersion(),
                            main.getProperties(),
                            main.getPath()));
                }
                // If deployBuildPom is false, we simply don't add the build POM to the result