Add a requiresEntity boolean to quick form plugins to optionally prevent creating default instances.

modules/core/quick/src/Annotation/QuickForm.php

@@ -52,4 +52,11 @@ class QuickForm extends Plugin {
    */
   public $permissions;
 
+  /**
+   * Require a quick form instance entity to instantiate.
+   *
+   * @var bool
+   */
+  public $requiresEntity;
+
 }

modules/core/quick/src/Plugin/QuickForm/QuickFormBase.php

@@ -105,6 +105,13 @@ class QuickFormBase extends PluginBase implements QuickFormInterface, ContainerF
     return $this->pluginDefinition['helpText'] ?? '';
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function requiresEntity() {
+    return $this->pluginDefinition['requiresEntity'] ?? FALSE;
+  }
+
   /**
    * {@inheritdoc}
    */

modules/core/quick/src/Plugin/QuickForm/QuickFormInterface.php

@@ -71,6 +71,14 @@ interface QuickFormInterface extends FormInterface {
    */
   public function getPermissions();
 
+  /**
+   * Whether the plugin requires a quick form instance configuration entity.
+   *
+   * @return bool
+   *   Boolean.
+   */
+  public function requiresEntity();
+
   /**
    * Checks access for the quick form.
    *

modules/core/quick/src/QuickFormInstanceManager.php

@@ -64,9 +64,10 @@ class QuickFormInstanceManager implements QuickFormInstanceManagerInterface {
         $instances += $entities;
       }
 
-      // If there are no config entities, create a new (unsaved) config entity
-      // with default values from the plugin.
-      else {
+      // Or, if this plugin does not require a quick form instance configuration
+      // entity, then add a new (unsaved) config entity with default values from
+      // the plugin.
+      elseif (empty($plugin['requiresEntity'])) {
         $instances[$plugin['id']] = QuickFormInstance::create(['id' => $plugin['id'], 'plugin' => $plugin['id']]);
       }
     }
@@ -86,9 +87,15 @@ class QuickFormInstanceManager implements QuickFormInstanceManagerInterface {
       return $entity;
     }
 
-    // Otherwise, create a new (unsaved) config entity with default values from
+    // Or, if this plugin does not require a quick form instance configuration
+    // entity, then add a new (unsaved) config entity with default values from
     // the plugin.
-    return QuickFormInstance::create(['id' => $id, 'plugin' => $id]);
+    elseif (empty($plugin['requiresEntity'])) {
+      return QuickFormInstance::create(['id' => $id, 'plugin' => $id]);
+    }
+
+    // No quick form could be instantiated.
+    return NULL;
   }
 
 }