Issue #3247683 by Wim Leers, lauriii, bnjmnm, Reinmar: Disable CKEditor 5's automatic link decorators (in Drupal filters should be used instead)

core/modules/ckeditor5/js/ckeditor5_plugins/drupalMedia/src/drupallinkmedia/drupallinkmediaediting.js

@@ -352,6 +352,13 @@ export default class DrupalLinkMediaEditing extends Plugin {
     editor.conversion.for('dataDowncast').add(dataDowncastMediaLink());
 
     this._enableManualDecorators();
+
+    const linkCommand = editor.commands.get('link');
+    if (linkCommand.automaticDecorators.length > 0) {
+      throw new Error(
+        'The Drupal Media plugin is not compatible with automatic link decorators. To use Drupal Media, disable any plugins providing automatic link decorators.',
+      );
+    }
   }
 
   /**

core/modules/ckeditor5/src/Plugin/CKEditor5PluginDefinition.php

@@ -90,6 +90,27 @@ final class CKEditor5PluginDefinition extends PluginDefinition implements Plugin
     if (!isset($definition['ckeditor5']['plugins'])) {
       throw new InvalidPluginDefinitionException($id, sprintf('The "%s" CKEditor 5 plugin definition must contain a "ckeditor5.plugins" key.', $id));
     }
+
+    // Automatic link decorators make sense in CKEditor 5, where the generated
+    // HTML must be assumed to be served as-is. But it does not make sense in
+    // in Drupal, where we prefer not storing (hardcoding) such decisions in the
+    // database. Drupal instead filters it on output, using the filter system.
+    if (isset($definition['ckeditor5']['config']['link'])) {
+      // @see https://ckeditor.com/docs/ckeditor5/latest/api/module_link_link-LinkDecoratorAutomaticDefinition.html
+      if (isset($definition['ckeditor5']['config']['link']['decorators']) && is_array($definition['ckeditor5']['config']['link']['decorators'])) {
+        foreach ($definition['ckeditor5']['config']['link']['decorators'] as $decorator) {
+          if ($decorator['mode'] === 'automatic') {
+            throw new InvalidPluginDefinitionException($id, sprintf('The "%s" CKEditor 5 plugin definition specifies an automatic decorator, this is not supported. Use the Drupal filter system instead.', $id));
+          }
+        }
+      }
+      // CKEditor 5 offers one preconfigured automatic link decorator under a
+      // special config flag.
+      // @see https://ckeditor.com/docs/ckeditor5/latest/api/module_link_link-LinkConfig.html#member-addTargetToExternalLinks
+      if (isset($definition['ckeditor5']['config']['link']['addTargetToExternalLinks']) && $definition['ckeditor5']['config']['link']['addTargetToExternalLinks']) {
+        throw new InvalidPluginDefinitionException($id, sprintf('The "%s" CKEditor 5 plugin definition specifies an automatic decorator, this is not supported. Use the Drupal filter system instead.', $id));
+      }
+    }
   }
 
   /**

core/modules/ckeditor5/tests/modules/ckeditor5_automatic_link_decorator_test/ckeditor5_automatic_link_decorator_test.ckeditor5.yml

@@ -0,0 +1,17 @@
+ckeditor5_automatic_link_decorator_test_llamaClass:
+  ckeditor5:
+    plugins: []
+    config:
+      link:
+        decorators:
+          pinkColor:
+            mode: 'automatic'
+            attributes:
+              class: 'llama'
+  drupal:
+    label: Links must have 'llama' class!
+    elements:
+      - <a class>
+    conditions:
+      plugins:
+        - ckeditor5_link

core/modules/ckeditor5/tests/modules/ckeditor5_automatic_link_decorator_test/ckeditor5_automatic_link_decorator_test.info.yml

@@ -0,0 +1,6 @@
+name: CKEditor 5 Automatic Link Decorator Test
+type: module
+description: "Provides infrastructure for testing CKEditor 5 automatic link decorators."
+package: Testing
+dependencies:
+  - ckeditor5:ckeditor5

core/modules/ckeditor5/tests/modules/ckeditor5_automatic_link_decorator_test_2/ckeditor5_automatic_link_decorator_test_2.ckeditor5.yml

@@ -0,0 +1,13 @@
+ckeditor5_automatic_link_decorator_test_2_addTargetToExternalLinks:
+  ckeditor5:
+    plugins: []
+    config:
+      link:
+        addTargetToExternalLinks: true
+  drupal:
+    label: Open external links in a new tab
+    elements:
+      - <a target="_blank" rel="noopener noreferrer">
+    conditions:
+      plugins:
+        - ckeditor5_link

core/modules/ckeditor5/tests/modules/ckeditor5_automatic_link_decorator_test_2/ckeditor5_automatic_link_decorator_test_2.info.yml

@@ -0,0 +1,6 @@
+name: CKEditor 5 Automatic Link Decorator Test (External links)
+type: module
+description: "Provides infrastructure for testing CKEditor 5 external links automatic link decorator."
+package: Testing
+dependencies:
+  - ckeditor5:ckeditor5

core/modules/ckeditor5/tests/src/Kernel/CKEditor5PluginManagerTest.php

@@ -1466,4 +1466,28 @@ PHP,
     ];
   }
 
+  /**
+   * @covers \Drupal\ckeditor5\Plugin\CKEditor5PluginDefinition::validateCKEditor5Aspects()
+   */
+  public function testAutomaticLinkDecoratorsDisallowed(): void {
+    $this->expectException(InvalidPluginDefinitionException::class);
+    $this->expectExceptionMessage('The "ckeditor5_automatic_link_decorator_test_llamaClass" CKEditor 5 plugin definition specifies an automatic decorator, this is not supported. Use the Drupal filter system instead.');
+
+    $this->enableModules(['ckeditor5_automatic_link_decorator_test']);
+
+    $this->manager->getDefinitions();
+  }
+
+  /**
+   * @covers \Drupal\ckeditor5\Plugin\CKEditor5PluginDefinition::validateCKEditor5Aspects()
+   */
+  public function testExternalLinkAutomaticLinkDecoratorDisallowed(): void {
+    $this->expectException(InvalidPluginDefinitionException::class);
+    $this->expectExceptionMessage('The "ckeditor5_automatic_link_decorator_test_2_addTargetToExternalLinks" CKEditor 5 plugin definition specifies an automatic decorator, this is not supported. Use the Drupal filter system instead.');
+
+    $this->enableModules(['ckeditor5_automatic_link_decorator_test_2']);
+
+    $this->manager->getDefinitions();
+  }
+
 }