Issue #3391677 by bohart: Added support both hook_form_BASE_FORM_ID_alter and hook_form_FORM_ID_alter hooks for MailerPolicy entity edit form.

src/Form/PolicyEditForm.php

@@ -10,6 +10,23 @@ use Drupal\Core\Form\FormStateInterface;
  */
 class PolicyEditForm extends EntityForm {
 
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    // Generates a unique form ID for each policy form. Examples/explanations:
+    // - mailer_policy_all_all_edit_form: for All/All policy.
+    // - mailer_policy_type_all_edit_form: for All policy of the type.
+    // - mailer_policy_type_subtype_edit_form: for other policies.
+    return implode("_", [
+      $this->getEntity()->getEntityTypeId(),
+      $this->getEntity()->getType() ?? "all",
+      $this->getEntity()->getSubType() ?? "all",
+      $this->operation,
+      "form",
+    ]);
+  }
+
   /**
    * {@inheritdoc}
    */

[Adam Shepherd]

I suggest we should use $this->getEntity()->id() instead of these two. It will include the type, sub-type and entity ID of the mailer policy, in a format that is already well-known.