Issue #3495982 by just_like_good_vibes, grimreaper: Not possible to display a...

Issue #3495982 by just_like_good_vibes, grimreaper: Not possible to display a comment field in Layout Builder

src/Plugin/UiPatterns/PropType/SlotPropType.php

@@ -36,7 +36,28 @@ class SlotPropType extends PropTypePluginBase {
     if (is_string($value)) {
       return ['#children' => Markup::create($value)];
     }
-    if (is_array($value) && empty(Element::properties($value))) {
+    if (!is_array($value)) {
+      return empty($value) ? ['#cache' => []] : ['#plain_text' => (string) $value];
+    }
+    return self::cleanRenderArray($value);
+  }
+
+  /**
+   * Clean a render array.
+   *
+   * @param array $value
+   *   The render array to clean.
+   *
+   * @return array
+   *   The cleaned render array.
+   */
+  protected static function cleanRenderArray(array $value): mixed {
+    if (empty($value)) {
+      // Element::isRenderArray() returns FALSE for empty arrays.
+      return ['#cache' => []];
+    }
+    $element_properties = Element::properties($value);
+    if (empty($element_properties)) {
       // Twig `is sequence` and `is mapping `tests are not useful when a list
       // of renderables has mapping keys (non consecutive, strings) instead of
       // sequence (integer, consecutive) keys. For example a list of blocks
@@ -44,6 +65,11 @@ class SlotPropType extends PropTypePluginBase {
       // So, transform this list of renderables to a proper Twig sequence.
       return array_map(static fn($item) => self::normalize($item), array_is_list($value) ? $value : array_values($value));
     }
+    foreach ($value as $key => & $item) {
+      if (!in_array($key, $element_properties, TRUE)) {
+        $item = self::normalize($item);
+      }
+    }
     return $value;
   }
 

tests/src/Kernel/PropTypeNormalization/SlotPropTypeTest.php

@@ -41,7 +41,7 @@ class SlotPropTypeTest extends PropTypeNormalizationTestBase {
    */
   public static function normalizationTests() : array {
     return [
-      "null value" => [NULL, NULL],
+      "null value" => [NULL, ["#cache" => []]],
     ];
   }
 
@@ -68,6 +68,10 @@ class SlotPropTypeTest extends PropTypeNormalizationTestBase {
         ["b" => ["#weight" => 2, "#markup" => "slot"], "a" => ["#weight" => 1, "#markup" => "my "]],
         "my slot",
       ],
+      "render array special" => [
+        [0 => ["#markup" => "my slot", "randomKey" => []]],
+        "my slot",
+      ],
     ];
   }