Disallow some blocks

Closes #3460784

src/Plugin/UiPatterns/Source/BlockSource.php

@@ -31,11 +31,10 @@ use Symfony\Component\DependencyInjection\ContainerInterface;
 #[Source(
   id: 'block',
   label: new TranslatableMarkup('Block'),
-  description: new TranslatableMarkup('instantiate a block'),
+  description: new TranslatableMarkup('A block plugin from a whitelist.'),
   prop_types: ['slot']
 )]
 class BlockSource extends SourcePluginBase {
-
   /**
    * Block to be rendered.
    *
@@ -150,16 +149,13 @@ class BlockSource extends SourcePluginBase {
       '#executes_submit_callback' => FALSE,
       '#empty_value' => '',
       '#empty_option' => $this->t('- None -'),
-      '#required' => TRUE,
+      '#required' => FALSE,
     ];
     $form["settings"] = [
       '#type' => 'container',
       '#attributes' => ["id" => $wrapper_id],
       "#tree" => TRUE,
     ];
-    // @todo support block settings form validation.
-    // Ass seen from
-    // \Drupal\layout_builder\Form\ConfigureBlockFormBase::validateForm
     $block = $this->getBlock($plugin_id);
     if ($block) {
       // Create a block entity.
@@ -273,14 +269,16 @@ class BlockSource extends SourcePluginBase {
   protected function listBlockDefinitions() : array {
     $context_for_block_discovery = $this->context;
     $definitions = $this->blockManager->getFilteredDefinitions('ui_patterns', $context_for_block_discovery, []);
+    // Filter plugins based on the flag 'ui_patterns_compatibility'.
+    // @see function ui_patterns_plugin_filter_block__ui_patterns_alter
+    // from ui_patterns.module file
+    $definitions = array_filter($definitions, function ($definition, $plugin_id) {
+      return !isset($definition['_ui_patterns_compatible']) || $definition['_ui_patterns_compatible'];
+    }, ARRAY_FILTER_USE_BOTH);
+    // Filter based on contexts.
     $definitions = $this->contextHandler->filterPluginDefinitionsByContexts($context_for_block_discovery, $definitions);
     // Order by category, and then by admin label.
     $definitions = $this->blockManager->getSortedDefinitions($definitions);
-    /*
-    // Filter out definitions that are not intended to be placed by the UI.
-    $definitions = array_filter($definitions, function (array $definition) {
-    return empty($definition['_block_ui_hidden']);
-    });*/
     return $definitions;
   }