Issue #2906028 by mglaman: Add theme suggestions for the checkout order summary and completion message templates

Author: mglaman

modules/checkout/commerce_checkout.module

@@ -45,16 +45,46 @@ function commerce_checkout_theme() {
   return $theme;
 }
 
+/**
+ * Implements hook_theme_suggestions_HOOK().
+ */
+function commerce_checkout_theme_suggestions_commerce_checkout_completion_message(array $variables) {
+  /** @var \Drupal\commerce_checkout\Entity\CheckoutFlowInterface $checkout_flow */
+  $checkout_flow = $variables['order_entity']->get('checkout_flow')->entity;
+  $original = $variables['theme_hook_original'];
+  $suggestions = [];
+  $suggestions[] = $original;
+  $suggestions[] = $original . '__' . $checkout_flow->getPluginId();
+  $suggestions[] = $original . '__' . $checkout_flow->id();
+}
+
+/**
+ * Implements hook_theme_suggestions_HOOK().
+ */
+function commerce_checkout_theme_suggestions_commerce_checkout_order_summary(array $variables) {
+  /** @var \Drupal\commerce_checkout\Entity\CheckoutFlowInterface $checkout_flow */
+  $checkout_flow = $variables['order_entity']->get('checkout_flow')->entity;
+  $original = $variables['theme_hook_original'];
+  $suggestions = [];
+  $suggestions[] = $original;
+  $suggestions[] = $original . '__' . $checkout_flow->getPluginId();
+  $suggestions[] = $original . '__' . $checkout_flow->id();
+}
+
 /**
  * Implements hook_theme_suggestions_HOOK().
  */
 function commerce_checkout_theme_suggestions_commerce_checkout_form(array $variables) {
   $original = $variables['theme_hook_original'];
   $suggestions = [];
   $suggestions[] = $original;
+  $suggestions[] = $original . '__' . $variables['form']['#plugin_id'];
+  $suggestions[] = $original . '__' . $variables['form']['#entity_id'];
   // If the checkout form has a sidebar, suggest the enhanced layout.
   if (isset($variables['form']['sidebar']) && Element::isVisibleElement($variables['form']['sidebar'])) {
     $suggestions[] = $original . '__with_sidebar';
+    $suggestions[] = $original . '__' . $variables['form']['#plugin_id'] . '__with_sidebar';
+    $suggestions[] = $original . '__' . $variables['form']['#entity_id'] . '__with_sidebar';
   }
 
   return $suggestions;

modules/checkout/src/Plugin/Commerce/CheckoutFlow/CheckoutFlowBase.php

@@ -257,6 +257,8 @@ public function buildForm(array $form, FormStateInterface $form_state, $step_id
 
     $steps = $this->getVisibleSteps();
     $form['#tree'] = TRUE;
+    $form['#entity_id'] = $this->entityId;
+    $form['#plugin_id'] = $this->pluginId;
     $form['#step_id'] = $step_id;
     $form['#title'] = $steps[$step_id]['label'];
     $form['#theme'] = ['commerce_checkout_form'];