GradleDocumentationExtension extension = project.getExtensions().getByType(GradleDocumentationExtension.class);
        generateDefaultImports(project, tasks, extension);
        generateUserManual(project, tasks, layout, extension);

        checkXrefLinksInUserManualAreValid(layout, tasks, extension);
        checkMultiLangSnippetsAreValid(layout, tasks, extension);

     * @param extension
     *            The extension.
     * @return The resource path.
     */
    public static String getResourcePath(final String path, final String extension) {
        assertArgumentNotNull("path", path);

        if (extension == null) {
            return path;
        }
        final String ext = "." + extension;
        if (path.endsWith(ext)) {

            releaseNotes.getBaseCssFile().convention(extension.getSourceRoot().file("css/base.css"));
            releaseNotes.getReleaseNotesCssFile().convention(extension.getSourceRoot().file("css/release-notes.css"));
            releaseNotes.getReleaseNotesJsFile().convention(extension.getSourceRoot().file("release/content/releaseIssues.js"));
            releaseNotes.getReleaseNotesAssets().convention(extension.getSourceRoot().dir("release/release-notes-assets"));

            return getNotifierKey(notifier);
        }
    }

    /**
     * KeyComputer for Extension
     */
    private class ExtensionKeyComputer implements KeyComputer<Extension> {
        @Override
        public Object key(Extension extension) {
            return getExtensionKey(extension);
        }
    }

    /**
     * KeyComputer for Resource
     */

        private final TestRerunTaskExtension extension;

        InitTaskAction(TestRerunTaskExtension extension) {
            this.extension = extension;
        }

        @Override
        public void execute(Task task) {
            RerunTestExecuter retryTestExecuter = createRetryTestExecuter(task, extension);
            setTestExecuter(task, retryTestExecuter);
        }
    }

        this.artifactId = (artifactId != null && !artifactId.isEmpty()) ? artifactId : null;
        this.classifier = (classifier != null && !classifier.isEmpty()) ? classifier : null;
        this.extension = (extension != null && !extension.isEmpty()) ? extension : null;
        this.version = (version != null && !version.isEmpty()) ? version : null;
        this.message = (message != null && !message.isEmpty()) ? message : null;
    }

    @Override

  private val typeHintStack = mutableListOf<Any?>()

  /**
   * The type hint for the current object. Used to pick adapters based on other fields, such as
   * in extensions which have different types depending on their extension ID.
   */
  var typeHint: Any?
    get() = typeHintStack.lastOrNull()
    set(value) {
      typeHintStack[typeHintStack.size - 1] = value
    }

import static org.junit.jupiter.api.Assertions.assertTrue;

/**
 * Tests {@code Extension}.
 *
 */
class ExtensionTest {

    @Test
    void testHashCodeNullSafe() {
        new Extension().hashCode();
    }

    @Test
    void testEqualsNullSafe() {
        assertFalse(new Extension().equals(null));

        new Extension().equals(new Extension());
    }

    @Test
    void testEqualsIdentity() {

maven.user.toolchains         = ${maven.user.conf}/toolchains.xml

#
# Extensions
#
maven.installation.extensions = ${maven.installation.conf}/extensions.xml
maven.project.extensions      = ${maven.project.conf}/extensions.xml
maven.user.extensions         = ${maven.user.conf}/extensions.xml

#
# Maven central repository URL.
#

    private final CoreExtensionEntry extension;
    private final UnaryOperator<String> callback;
    private final DefaultInterpolator interpolator = new DefaultInterpolator();

    public ExtensionConfigurationModule(CoreExtensionEntry extension, UnaryOperator<String> callback) {
        this.extension = extension;
        this.callback = callback;
    }

    @Override