Issue #3474822 by pdureau, sea2709, smustgrave, just_like_good_vibes: Normalize attributes values

Closes #3474822

src/Plugin/UiPatterns/PropType/AttributesPropType.php

@@ -4,8 +4,12 @@ declare(strict_types=1);
 
 namespace Drupal\ui_patterns\Plugin\UiPatterns\PropType;
 
+use Drupal\Component\Render\MarkupInterface;
+use Drupal\Core\Render\Element;
+use Drupal\Core\Render\RenderableInterface;
 use Drupal\Core\StringTranslation\TranslatableMarkup;
 use Drupal\Core\Template\Attribute;
+use Drupal\Core\Url;
 use Drupal\ui_patterns\Attribute\PropType;
 use Drupal\ui_patterns\PropTypePluginBase;
 
@@ -49,12 +53,98 @@ class AttributesPropType extends PropTypePluginBase {
     plugins are expected to return a mapping to not break SDC prop validation
     against the prop type schema.
      */
-    if (is_a($value, '\Drupal\Core\Template\Attribute')) {
-      return $value->toArray();
+    if (is_array($value)) {
+      // Attribute::createAttributeValue() is alread normalizing some stuff:
+      // - 'class' attribute must be a list
+      // - MarkupInterface values must be resolved.
+      $value = (new Attribute($value))->toArray();
+    }
+    elseif (is_a($value, '\Drupal\Core\Template\Attribute')) {
+      $value = $value->toArray();
+    }
+    else {
+      return [];
+    }
+    if (array_is_list($value)) {
+      // @todo
+    }
+    foreach ($value as $attr => $attr_value) {
+      $value[$attr] = self::normalizeAttrValue($attr_value);
+    }
+    return $value;
+  }
+
+  /**
+   * Normalize attribute value.
+   */
+  protected static function normalizeAttrValue(mixed $value): mixed {
+    if (is_object($value)) {
+      return self::normalizeObject($value);
+    }
+    if (is_array($value) && array_is_list($value)) {
+      return self::normalizeList($value);
+    }
+    if (is_array($value) && !array_is_list($value)) {
+      return self::normalizeMapping($value);
+    }
+    // Integer and number are always allowed values.
+    if (is_int($value) || is_float($value)) {
+      return $value;
+    }
+    // We don't allow markup in attribute value.
+    return strip_tags((string) $value);
+  }
+
+  /**
+   * Normalize object attribute value.
+   */
+  protected static function normalizeObject(object $value): array|string {
+    if ($value instanceof Url) {
+      return $value->toString();
+    }
+    if ($value instanceof RenderableInterface) {
+      return static::normalizeMapping($value->toRenderable());
+    }
+    if ($value instanceof MarkupInterface) {
+      return (string) $value;
+    }
+    if ($value instanceof \Stringable) {
+      return (string) $value;
+    }
+    // Instead of keeping an unexpected object, we return PHP namespace.
+    // It will be valid and can inform the component user about its mistake.
+    return get_class($value);
+  }
+
+  /**
+   * Normalize list attribute value.
+   */
+  protected static function normalizeList(array $value): array {
+    // Flatten nested arrays.
+    foreach ($value as $index => $item) {
+      if (is_array($item)) {
+        // We encode to JSON because we don't know how deep is the nesting.
+        $value[$index] = json_encode($item);
+      }
     }
     return $value;
   }
 
+  /**
+   * Normalize mapping attribute value.
+   */
+  protected static function normalizeMapping(array $value): array|string {
+    if (!empty(Element::properties($value))) {
+      // This is a render array.
+      // It would be great to render it here
+      // $value = \Drupal::service('renderer')->render($value);
+      // return strip_tags($value);
+      // But let's alert the component user by JSON encoding the value for now.
+      return (string) json_encode($value);
+    }
+    return static::normalizeList(array_values($value));
+  }
+
   /**
    * {@inheritdoc}
    */