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);

        CoreExtension oldExtension = new CoreExtension();
        oldExtension.setGroupId(extension.getGroupId());
        oldExtension.setArtifactId(extension.getArtifactId());
        oldExtension.setVersion(extension.getVersion());
        if (extension.getClassLoadingStrategy() != null) {
            oldExtension.setClassLoadingStrategy(extension.getClassLoadingStrategy());
        }
        this.extension = oldExtension;
    }

                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,

        when(artifact2.getVersion()).thenReturn("1");
        artifacts.add(artifact2);

        return artifacts;
    }

    private Model newTestModel() {
        Model model = new Model();
        model.setGroupId("modelGroup1");
        model.setArtifactId("modelArtifact1");
        model.setVersion("modelVersion1");

        return model;
    }

    @Test

    public PluginDescriptor() {}

    public PluginDescriptor(PluginDescriptor original) {
        this.setGroupId(original.getGroupId());
        this.setArtifactId(original.getArtifactId());
        this.setVersion(original.getVersion());
        this.setGoalPrefix(original.getGoalPrefix());
        this.setInheritedByDefault(original.isInheritedByDefault());
        this.setName(original.getName());

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

    String getGroupId();

    String getArtifactId();

    String getVersion();

    String getClassifier();

    String getExtension();

    String getType();

    String getCoordinatesString();

    @Nonnull
    static ArtifactCoordinatesFactoryRequest build(

        // does nothing
    }

    DefaultPluginVersionResult(String version) {
        this.version = version;
    }

    @Override
    public String getVersion() {
        return version;
    }

    public void setVersion(String version) {
        this.version = version;
    }

    @Override
    public ArtifactRepository getRepository() {
        return repository;
    }

            try {
                Model model = read(project.getFile().toPath());
                String version = model.getVersion();
                if (version == null && model.getParent() != null) {
                    version = model.getParent().getVersion();
                }
                String newVersion;
                if (version != null) {

    }

    private MavenProject getMavenProject(Project project) {
        return ((DefaultProject) project).getProject();
    }

    private static InternalSession getSession(Project project) {
        return ((DefaultProject) project).getSession();
    }

            groupId = model.getParent().getGroupId();
        }

        String artifactId = model.getArtifactId();

        String version = model.getVersion();
        if (version == null && model.getParent() != null) {
            version = model.getParent().getVersion();
        }
        if (version == null) {
            version = "[unknown-version]";
        }

        return toId(groupId, artifactId, version);
    }