Resolve #3418165 "Support emptyoption for"

.tugboat/config.yml

+services:
+  php:
+    # Specify the version of Drupal you wish to use for Tugboat below.
+    image: q0rban/tugboat-drupal:10
+    default: true
+    http: false
+    depends: mysql
+    commands:
+      update: |
+        set -eux
+        # Check out a branch using the unique Tugboat ID for this repository, to
+        # ensure we don't clobber an existing branch.
+        git checkout -b $TUGBOAT_REPO_ID
+        # Composer is hungry. You need a Tugboat project with a pretty sizeable
+        # chunk of memory.
+        export COMPOSER_MEMORY_LIMIT=-1
+        # This is an environment variable we added in the Dockerfile that
+        # provides the path to Drupal composer root (not the web root).
+        cd $DRUPAL_COMPOSER_ROOT
+        # If you need to change the minimum stability due to downstream
+        # dependencies, you can modify 'stable' below to your needs:
+        # see https://getcomposer.org/doc/04-schema.md#minimum-stability
+        composer config minimum-stability stable
+        # We configure the Drupal project to use the checkout of the module as a
+        # Composer package repository.
+        composer config repositories.tugboat vcs $TUGBOAT_ROOT
+        # Now we can require this module, specifing the branch name we created
+        # above that uses the $TUGBOAT_REPO_ID environment variable.
+        composer require drupal/typed_link:dev-$TUGBOAT_REPO_ID
+        # Install Drupal on the site.
+        vendor/bin/drush \
+          --yes \
+          --db-url=mysql://tugboat:tugboat@mysql:3306/tugboat \
+          --site-name="Live preview for ${TUGBOAT_PREVIEW_NAME}" \
+          --account-pass=admin \
+          site:install standard
+        # Set up the files directory permissions.
+        mkdir -p $DRUPAL_DOCROOT/sites/default/files
+        chgrp -R www-data $DRUPAL_DOCROOT/sites/default/files
+        chmod 2775 $DRUPAL_DOCROOT/sites/default/files
+        chmod -R g+w $DRUPAL_DOCROOT/sites/default/files
+        # Enable the module.
+        vendor/bin/drush --yes pm:enable typed_link
+      build: |
+        set -eux
+        # Delete and re-check out this branch in case this is built from a Base Preview.
+        git branch -D $TUGBOAT_REPO_ID && git checkout -b $TUGBOAT_REPO_ID || true
+        export COMPOSER_MEMORY_LIMIT=-1
+        cd $DRUPAL_COMPOSER_ROOT
+        composer install --optimize-autoloader
+        # Update this module, including all dependencies.
+        composer update drupal/typed_link --with-all-dependencies
+        vendor/bin/drush --yes updb
+        vendor/bin/drush cache:rebuild
+  mysql:
+    image: tugboatqa/mariadb

src/Plugin/Field/FieldFormatter/TypedLinkFormatter.php

@@ -24,7 +24,7 @@ class TypedLinkFormatter extends LinkFormatter {
   /**
    * {@inheritdoc}
    */
-  public function viewElements(FieldItemListInterface $items, $langcode) {
+  public function viewElements(FieldItemListInterface $items, $langcode): array {
     $elements = parent::viewElements($items, $langcode);
 
     // Only collect allowed options if there are actually items to display.
@@ -39,7 +39,7 @@ class TypedLinkFormatter extends LinkFormatter {
         $value = $item->link_type;
         // If the stored value is in the current set of allowed values, display
         // the associated label, otherwise just display the raw value.
-        $output = isset($options[$value]) ? $options[$value] : $value;
+        $output = $options[$value] ?? $value;
         $elements[$delta]['type'] = [
           '#markup' => $output,
           '#allowed_tags' => FieldFilteredMarkup::allowedTags(),

src/Plugin/Field/FieldType/TypedLinkItem.php

@@ -29,11 +29,11 @@ use Drupal\options\Plugin\Field\FieldType\ListStringItem;
 class TypedLinkItem extends LinkItem implements OptionsProviderInterface {
 
   /**
-   * An string option field.
+   * A string option field.
    *
    * @var \Drupal\options\Plugin\Field\FieldType\ListStringItem
    */
-  protected $optionField;
+  protected ListStringItem $optionField;
 
   /**
    * {@inheritdoc}
@@ -51,7 +51,7 @@ class TypedLinkItem extends LinkItem implements OptionsProviderInterface {
     $properties['link_type'] = DataDefinition::create('string')
       ->setLabel(t('Link Type'))
       ->addConstraint('Length', ['max' => 255])
-      ->setRequired(TRUE);
+      ->setRequired(FALSE);
 
     return $properties;
   }

src/Plugin/Field/FieldWidget/TypedLinkWidget.php

@@ -23,16 +23,21 @@ use Drupal\link\Plugin\Field\FieldWidget\LinkWidget;
  */
 class TypedLinkWidget extends LinkWidget {
 
-  private $column;
-  private $required;
-  private $options;
+  /**
+   * Widget options.
+   *
+   * @var array
+   */
+  private array $options;
 
   /**
-   * {@inheritdoc}
+   * Get the column name of the field.
+   *
+   * @return string
+   *   The column name.
    */
-  public function __construct($plugin_id, $plugin_definition, FieldDefinitionInterface $field_definition, array $settings, array $third_party_settings) {
-    parent::__construct($plugin_id, $plugin_definition, $field_definition, $settings, $third_party_settings);
-    $this->column = $field_definition->getFieldStorageDefinition()->getMainPropertyName();
+  private function getColumn(): string {
+    return $this->fieldDefinition->getFieldStorageDefinition()->getMainPropertyName();
   }
 
   /**
@@ -40,15 +45,22 @@ class TypedLinkWidget extends LinkWidget {
    */
   public function formElement(FieldItemListInterface $items, $delta, array $element, array &$form, FormStateInterface $form_state) {
     $element = parent::formElement($items, $delta, $element, $form, $form_state);
-    $this->required = $element['#required'];
 
     $element['link_type'] = [
       '#title' => $this->t('Link type'),
       '#type' => 'select',
       '#options' => $this->getOptions($items->getEntity()),
       '#default_value' => $this->getSelectedOption($items[$delta]),
-      // Do not display a 'multiple' select box if there is only one option.
+      '#empty_option' => $this->t('- Select -'),
       '#multiple' => FALSE,
+      '#required' => $element['#required'],
+      '#states' => [
+        'required' => [
+          ':input[name="' . $items->getName() . '[' . $delta . '][uri]' . '"]' => [
+            'filled' => TRUE,
+          ],
+        ],
+      ],
     ];
 
     return $element;
@@ -68,7 +80,7 @@ class TypedLinkWidget extends LinkWidget {
       // Limit the settable options for the current user account.
       $options = $this->fieldDefinition
         ->getFieldStorageDefinition()
-        ->getOptionsProvider($this->column, $entity)
+        ->getOptionsProvider($this->getColumn(), $entity)
         ->getSettableOptions(\Drupal::currentUser());
 
       $module_handler = \Drupal::moduleHandler();
@@ -100,7 +112,7 @@ class TypedLinkWidget extends LinkWidget {
     // We need to check against a flat list of options.
     $flat_options = OptGroup::flattenOptions($this->getOptions($item->getEntity()));
 
-    $value = $item->{$this->column};
+    $value = $item->{$this->getColumn()};
     $selected_option = NULL;
     // Keep the value if it actually is in the list of options (needs to be
     // checked against the flat list).
@@ -112,7 +124,10 @@ class TypedLinkWidget extends LinkWidget {
   }
 
   /**
-   * {@inheritdoc}
+   * Sanitize label.
+   *
+   * @param string $label
+   *   The label.
    */
   protected function sanitizeLabel(&$label) {
     // Select form inputs allow unencoded HTML entities, but no HTML tags.