Pass membership data in form_state for roles add/remove form.

og.api.php

@@ -9,6 +9,7 @@
 
 use Drupal\Core\Cache\CacheableMetadata;
 use Drupal\Core\Entity\EntityPublishedInterface;
+use Drupal\Core\Form\FormStateInterface;
 use Drupal\og\OgAccess;
 
 /**
@@ -54,6 +55,44 @@ function hook_og_user_access_alter(array &$permissions, CacheableMetadata $cache
   $cacheable_metadata->addCacheableDependency($config);
 }
 
+/**
+ * Implements hook_form_FORM_ID_alter().
+ */
+function hook_form_og_membership_remove_multiple_roles_action_form_alter(array &$form, FormStateInterface $form_state, string $form_id) {
+  // Get access to current group and selected memberships when we're on the role
+  // remove form.
+  /** @var \Drupal\og\OgMembershipInterface[] $memberships */
+  $memberships = $form_state->getTemporaryValue('selected_memberships');
+
+  $form['roles']['#options'] = array_filter($form['roles']['#options'], function ($key) use (&$form, $memberships) {
+    // Code to filter out options based on data from memberships and group.
+    $membership = reset($memberships);
+    $group = $membership->getGroup();
+    if ($group->id() != 9999) {
+      unset($form['roles']['#options'][$key]);
+    }
+  }, ARRAY_FILTER_USE_KEY);
+}
+
+/**
+ * Implements hook_form_FORM_ID_alter().
+ */
+function hook_form_og_membership_add_multiple_roles_action_form_alter(array &$form, FormStateInterface $form_state, string $form_id) {
+  // Get access to current group and selected memberships when we're on the role
+  // add form.
+  /** @var \Drupal\og\OgMembershipInterface[] $memberships */
+  $memberships = $form_state->getTemporaryValue('selected_memberships');
+
+  $form['roles']['#options'] = array_filter($form['roles']['#options'], function ($key) use (&$form, $memberships) {
+    // Code to filter out options based on data from memberships and group.
+    $membership = reset($memberships);
+    $group = $membership->getGroup();
+    if ($group->id() != 9999) {
+      unset($form['roles']['#options'][$key]);
+    }
+  }, ARRAY_FILTER_USE_KEY);
+}
+
 /**
  * @} End of "addtogroup hooks".
  */

src/Form/OgChangeMultipleRolesFormBase.php

@@ -93,6 +93,15 @@ public function buildForm(array $form, FormStateInterface $form_state) {
       '#value' => $this->t('Submit'),
     ];
 
+    // Set selected memberships in the form state. This can be used to alter
+    // the roles add/remove form.
+    $memberships = $this->getMemberships();
+    if (empty($memberships)) {
+      return $form;
+    }
+
+    $form_state->setTemporaryValue('selected_memberships', $memberships);
+
     return $form;
   }