Issue #3272516 by Wim Leers, yogeshmpawar, bnjmnm, catch: Deprecate FilterInterface::getHTMLRestrictions()' forbidden_tags functionality

core/modules/ckeditor5/src/HTMLRestrictions.php

@@ -37,9 +37,6 @@ use Drupal\filter\Plugin\FilterInterface;
  *
  * @see ::WILDCARD_ELEMENT_METHODS
  *
- * NOTE: Currently only supports the 'allowed' portion.
- * @todo Add support for "forbidden" tags in https://www.drupal.org/project/drupal/issues/3231336
- *
  * @internal
  */
 final class HTMLRestrictions {
@@ -341,12 +338,6 @@ final class HTMLRestrictions {
     }
 
     $restrictions = $object->getHTMLRestrictions();
-    if (!isset($restrictions['allowed'])) {
-      // @todo Handle HTML restrictor filters that only set forbidden_tags
-      //   https://www.drupal.org/project/ckeditor5/issues/3231336.
-      throw new \DomainException('text formats with only filters that forbid tags rather than allowing tags are not yet supported.');
-    }
-
     $allowed = $restrictions['allowed'];
 
     return new self($allowed);

core/modules/ckeditor5/src/Plugin/Validation/Constraint/FundamentalCompatibilityConstraint.php

@@ -25,13 +25,6 @@ class FundamentalCompatibilityConstraint extends Constraint {
    */
   public $noMarkupFiltersMessage = 'CKEditor 5 only works with HTML-based text formats. The "%filter_label" (%filter_plugin_id) filter implies this text format is not HTML anymore.';
 
-  /**
-   * The violation message when fundamental HTML elements are forbidden.
-   *
-   * @var string
-   */
-  public $forbiddenElementsMessage = 'CKEditor 5 needs at least the <p> and <br> tags to be allowed to be able to function. They are forbidden by the "%filter_label" (%filter_plugin_id) filter.';
-
   /**
    * The violation message when fundamental HTML elements are not allowed.
    *

core/modules/ckeditor5/src/Plugin/Validation/Constraint/FundamentalCompatibilityConstraintValidator.php

@@ -114,22 +114,7 @@ class FundamentalCompatibilityConstraintValidator extends ConstraintValidator im
    */
   private function checkHtmlRestrictionsAreCompatible(FilterFormatInterface $text_format, FundamentalCompatibilityConstraint $constraint): void {
     $fundamental = new HTMLRestrictions($this->pluginManager->getProvidedElements(self::FUNDAMENTAL_CKEDITOR5_PLUGINS));
-
-    // @todo Remove in favor of HTMLRestrictions::diff() in https://www.drupal.org/project/drupal/issues/3231336
     $html_restrictions = $text_format->getHtmlRestrictions();
-    $minimum_tags = array_keys($fundamental->getAllowedElements());
-    $forbidden_minimum_tags = isset($html_restrictions['forbidden_tags'])
-      ? array_diff($minimum_tags, $html_restrictions['forbidden_tags'])
-      : [];
-    if (!empty($forbidden_minimum_tags)) {
-      $offending_filter = static::findHtmlRestrictorFilterForbiddingTags($text_format, $minimum_tags);
-      $this->context->buildViolation($constraint->forbiddenElementsMessage)
-        ->setParameter('%filter_label', (string) $offending_filter->getLabel())
-        ->setParameter('%filter_plugin_id', $offending_filter->getPluginId())
-        ->addViolation();
-    }
-
-    // @todo Remove early return in https://www.drupal.org/project/drupal/issues/3231336
     if (!isset($html_restrictions['allowed'])) {
       return;
     }
@@ -212,47 +197,6 @@ class FundamentalCompatibilityConstraintValidator extends ConstraintValidator im
     }
   }
 
-  /**
-   * Analyzes a text format to find the filter not allowing required tags.
-   *
-   * @param \Drupal\filter\FilterFormatInterface $text_format
-   *   A text format whose filters to check for compatibility.
-   * @param string[] $required_tags
-   *   A list of HTML tags that are required.
-   *
-   * @return \Drupal\filter\Plugin\FilterInterface
-   *   The filter plugin instance not allowing the required tags.
-   *
-   * @throws \InvalidArgumentException
-   */
-  private static function findHtmlRestrictorFilterForbiddingTags(FilterFormatInterface $text_format, array $required_tags): FilterInterface {
-    // Get HTML restrictor filters that actually restrict HTML.
-    $filters = static::getFiltersInFormatOfType(
-      $text_format,
-      FilterInterface::TYPE_HTML_RESTRICTOR,
-      function (FilterInterface $filter) {
-        return $filter->getHTMLRestrictions() !== FALSE;
-      }
-    );
-
-    foreach ($filters as $filter) {
-      $restrictions = $filter->getHTMLRestrictions();
-
-      // @todo Fix
-      //   \Drupal\filter_test\Plugin\Filter\FilterTestRestrictTagsAndAttributes::getHTMLRestrictions(),
-      //   whose computed value for forbidden_tags does not comply with the API
-      //   https://www.drupal.org/project/drupal/issues/3231331.
-      if (array_keys($restrictions['forbidden_tags']) != range(0, count($restrictions['forbidden_tags']))) {
-        $restrictions['forbidden_tags'] = array_keys($restrictions['forbidden_tags']);
-      }
-      if (isset($restrictions['forbidden_tags']) && !empty(array_intersect($required_tags, $restrictions['forbidden_tags']))) {
-        return $filter;
-      }
-    }
-
-    throw new \InvalidArgumentException('This text format does not have a "tags forbidden" restriction that includes the required tags.');
-  }
-
   /**
    * Analyzes a text format to find the filter not allowing required tags.
    *

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

@@ -462,33 +462,6 @@ class ValidatorsTest extends KernelTestBase {
       ],
       'violations' => [],
     ];
-    $data['INVALID: forbidden tags'] = [
-      'settings' => [
-        'toolbar' => [
-          'items' => [],
-        ],
-        'plugins' => [],
-      ],
-      'image_upload' => [
-        'status' => FALSE,
-      ],
-      'filters' => [
-        'filter_test_restrict_tags_and_attributes' => [
-          'id' => 'filter_test_restrict_tags_and_attributes',
-          'provider' => 'filter_test',
-          'status' => TRUE,
-          'weight' => 0,
-          'settings' => [
-            'restrictions' => [
-              'forbidden_tags' => ['p' => FALSE],
-            ],
-          ],
-        ],
-      ],
-      'violations' => [
-        '' => 'CKEditor 5 needs at least the &lt;p&gt; and &lt;br&gt; tags to be allowed to be able to function. They are forbidden by the "<em class="placeholder">Tag and attribute restricting filter</em>" (<em class="placeholder">filter_test_restrict_tags_and_attributes</em>) filter.',
-      ],
-    ];
     $restricted_html_format_filters = Yaml::parseFile(__DIR__ . '/../../../../../profiles/standard/config/install/filter.format.restricted_html.yml')['filters'];
     $data['INVALID: the default restricted_html text format'] = [
       'settings' => [

core/modules/editor/src/EditorXssFilter/Standard.php

@@ -42,9 +42,9 @@ class Standard extends Xss implements EditorXssFilterInterface {
     // <embed>, for example? Then we would strip that tag, even though it is
     // allowed, thereby causing data loss!
     // Therefore, we want to be smarter still. We want to take into account
-    // which HTML tags are allowed and forbidden by the text format we're
+    // which HTML tags are allowed by the text format we're filtering for, and
-    // filtering for, and if we're switching from another text format, we want
+    // if we're switching from another text format, we want to take that
-    // to take that format's allowed and forbidden tags into account as well.
+    // format's allowed tags into account as well.
     // In other words: we only expect markup allowed in both the original and
     // the new format to continue to exist.
     $format_restrictions = $format->getHtmlRestrictions();
@@ -52,17 +52,6 @@ class Standard extends Xss implements EditorXssFilterInterface {
       $original_format_restrictions = $original_format->getHtmlRestrictions();
     }
 
-    // Any tags that are explicitly blacklisted by the text format must be
-    // appended to the list of default dangerous tags: if they're explicitly
-    // forbidden, then we must respect that configuration.
-    // When switching from another text format, we must use the union of
-    // forbidden tags: if either text format is more restrictive, then the
-    // safety expectations of *both* text formats apply.
-    $forbidden_tags = self::getForbiddenTags($format_restrictions);
-    if ($original_format !== NULL) {
-      $forbidden_tags = array_merge($forbidden_tags, self::getForbiddenTags($original_format_restrictions));
-    }
-
     // Any tags that are explicitly whitelisted by the text format must be
     // removed from the list of default dangerous tags: if they're explicitly
     // allowed, then we must respect that configuration.
@@ -78,9 +67,6 @@ class Standard extends Xss implements EditorXssFilterInterface {
     // formats.
     $blacklisted_tags = array_diff($dangerous_tags, $allowed_tags);
 
-    // Also blacklist tags that are explicitly forbidden in either text format.
-    $blacklisted_tags = array_merge($blacklisted_tags, $forbidden_tags);
-
     $output = static::filter($html, $blacklisted_tags);
 
     // Since data-attributes can contain encoded HTML markup that could be
@@ -140,26 +126,6 @@ class Standard extends Xss implements EditorXssFilterInterface {
     return $allowed_tags;
   }
 
-  /**
-   * Get all forbidden tags from a restrictions data structure.
-   *
-   * @param array|false $restrictions
-   *   Restrictions as returned by FilterInterface::getHTMLRestrictions().
-   *
-   * @return array
-   *   An array of forbidden HTML tags.
-   *
-   * @see \Drupal\filter\Plugin\Filter\FilterInterface::getHTMLRestrictions()
-   */
-  protected static function getForbiddenTags($restrictions) {
-    if ($restrictions === FALSE || !isset($restrictions['forbidden_tags'])) {
-      return [];
-    }
-    else {
-      return $restrictions['forbidden_tags'];
-    }
-  }
-
   /**
    * {@inheritdoc}
    */

core/modules/filter/src/Entity/FilterFormat.php

@@ -305,16 +305,6 @@ class FilterFormat extends ConfigEntityBase implements FilterFormatInterface, En
         // with the existing set, to ensure we only end up with the tags that are
         // allowed by *all* filters with an "allowed html" setting.
         else {
-          // Track the union of forbidden tags.
-          if (isset($new_restrictions['forbidden_tags'])) {
-            if (!isset($restrictions['forbidden_tags'])) {
-              $restrictions['forbidden_tags'] = $new_restrictions['forbidden_tags'];
-            }
-            else {
-              $restrictions['forbidden_tags'] = array_unique(array_merge($restrictions['forbidden_tags'], $new_restrictions['forbidden_tags']));
-            }
-          }
-
           // Track the intersection of allowed tags.
           if (isset($restrictions['allowed'])) {
             $intersection = $restrictions['allowed'];
@@ -372,32 +362,17 @@ class FilterFormat extends ConfigEntityBase implements FilterFormatInterface, En
             $restrictions['allowed'] = $intersection;
           }
 
+          // Simplification: if the only remaining allowed tag is the asterisk
+          // (which contains attribute restrictions that apply to all tags),
+          // then effectively nothing is allowed.
+          if (count($restrictions['allowed']) === 1 && array_key_exists('*', $restrictions['allowed'])) {
+            $restrictions['allowed'] = [];
+          }
+
           return $restrictions;
         }
       }, NULL);
 
-      // Simplification: if we have both allowed (intersected) and forbidden
-      // (unioned) tags, then remove any allowed tags that are also forbidden.
-      // Once complete, the list of allowed tags expresses all tag-level
-      // restrictions, and the list of forbidden tags can be removed.
-      if (isset($restrictions['allowed']) && isset($restrictions['forbidden_tags'])) {
-        foreach ($restrictions['forbidden_tags'] as $tag) {
-          if (isset($restrictions['allowed'][$tag])) {
-            unset($restrictions['allowed'][$tag]);
-          }
-        }
-        unset($restrictions['forbidden_tags']);
-      }
-
-      // Simplification: if the only remaining allowed tag is the asterisk
-      // (which contains attribute restrictions that apply to all tags), and
-      // there are no forbidden tags, then effectively nothing is allowed.
-      if (isset($restrictions['allowed'])) {
-        if (count($restrictions['allowed']) === 1 && array_key_exists('*', $restrictions['allowed']) && !isset($restrictions['forbidden_tags'])) {
-          $restrictions['allowed'] = [];
-        }
-      }
-
       return $restrictions;
     }
   }

core/modules/filter/src/FilterFormatInterface.php

@@ -72,10 +72,8 @@ interface FilterFormatInterface extends ConfigEntityInterface {
    *
    * @return array|false
    *   A structured array as returned by FilterInterface::getHTMLRestrictions(),
-   *   but with the intersection of all filters in this text format. The
+   *   but with the intersection of all filters in this text format. FALSE means
-   *   restrictions will either forbid or allow a list of tags. In the latter
+   *   there are no HTML restrictions.
-   *   case, it's possible that restrictions on attributes are also stored.
-   *   FALSE means there are no HTML restrictions.
    */
   public function getHtmlRestrictions();
 

core/modules/filter/src/Plugin/FilterInterface.php

@@ -184,9 +184,9 @@ interface FilterInterface extends ConfigurableInterface, DependentPluginInterfac
    * format.
    *
    * @return array|false
-   *   A nested array with *either* of the following keys:
+   *   A nested array with the following structure:
-   *     - 'allowed': (optional) the allowed tags as keys, and for each of those
+   *     - 'allowed': the allowed tags as keys, and for each of those tags
-   *       tags (keys) either of the following values:
+   *       (keys) either of the following values:
    *       - TRUE to indicate any attribute is allowed
    *       - FALSE to indicate no attributes are allowed
    *       - an array to convey attribute restrictions: the keys must be
@@ -198,7 +198,6 @@ interface FilterInterface extends ConfigurableInterface, DependentPluginInterfac
    *             be attribute values (which may use a wildcard, e.g. "xsd:*"),
    *             the possible values are TRUE or FALSE: to mark the attribute
    *             value as allowed or forbidden, respectively
-   *     -  'forbidden_tags': (optional) the forbidden tags
    *
    *   There is one special case: the "wildcard tag", "*": any attribute
    *   restrictions on that pseudotag apply to all tags.
@@ -243,13 +242,6 @@ interface FilterInterface extends ConfigurableInterface, DependentPluginInterfac
    *     )
    *     @endcode
    *
-   *   A simpler example, for a very coarse filter:
-   *     @code
-   *     array(
-   *       'forbidden_tags' => array('iframe', 'script')
-   *     )
-   *     @endcode
-   *
    *   The simplest example possible: a filter that doesn't allow any HTML:
    *     @code
    *     array(

core/modules/filter/tests/filter_test/config/schema/filter_test.schema.yml

@@ -14,9 +14,3 @@ filter_settings.filter_test_restrict_tags_and_attributes:
           sequence:
             type: ignore
             label: 'Tag and optionally list of attributes'
-        forbidden_tags:
-          type: sequence
-          label: 'Forbidden tags'
-          sequence:
-            type: boolean
-            label: 'Tag'

core/modules/filter/tests/filter_test/src/Plugin/Filter/FilterTestRestrictTagsAndAttributes.php

@@ -54,11 +54,6 @@ class FilterTestRestrictTagsAndAttributes extends FilterBase {
         }
       }
     }
-    if (isset($restrictions['forbidden_tags'])) {
-      foreach ($restrictions['forbidden_tags'] as $tag => $bool) {
-        $restrictions['forbidden_tags'][$tag] = (bool) $bool;
-      }
-    }
 
     return $restrictions;
   }

core/modules/filter/tests/src/Kernel/FilterAPITest.php

@@ -137,8 +137,11 @@ class FilterAPITest extends EntityKernelTestBase {
     $stupid_filtered_html_format->save();
     $this->assertSame(
       $stupid_filtered_html_format->getHtmlRestrictions(),
-      // No tag is allowed.
+      [
-      ['allowed' => []],
+        'allowed' => [
+          '*' => ['style' => FALSE, 'on*' => FALSE, 'lang' => TRUE, 'dir' => ['ltr' => TRUE, 'rtl' => TRUE]],
+        ],
+      ],
       'FilterFormatInterface::getHtmlRestrictions() works as expected for the stupid_filtered_html format.'
     );
     $this->assertSame(