Issue #2846890: Create a log entry when item is removed from cart or qty is changed programatically

modules/log/commerce_log.commerce_log_templates.yml

@@ -6,6 +6,10 @@ cart_item_removed:
   category: commerce_cart
   label: 'Removed from cart'
   template: '<p><em>{{ purchased_entity_label }}</em> removed from the cart.</p>'
+cart_item_quantity_changed:
+  category: commerce_cart
+  label: 'Quantity changed from cart'
+  template: '<p>Quantity of <em>{{ purchased_entity_label }}</em> changed in the cart from {{ original_quantity }} to {{ quantity }}.</p>'
 
 order_placed:
   category: commerce_order

modules/log/src/EventSubscriber/CartEventSubscriber.php

@@ -5,6 +5,7 @@
 use Drupal\commerce_cart\Event\CartEntityAddEvent;
 use Drupal\commerce_cart\Event\CartEvents;
 use Drupal\commerce_cart\Event\CartOrderItemRemoveEvent;
+use Drupal\commerce_cart\Event\CartOrderItemUpdateEvent;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 
@@ -34,6 +35,7 @@ public static function getSubscribedEvents() {
     $events = [
       CartEvents::CART_ENTITY_ADD => ['onCartEntityAdd', -100],
       CartEvents::CART_ORDER_ITEM_REMOVE => ['onCartOrderItemRemove', -100],
+      CartEvents::CART_ORDER_ITEM_UPDATE => ['onCartOrderItemUpdate', -100],
     ];
     return $events;
   }
@@ -66,4 +68,21 @@ public function onCartOrderItemRemove(CartOrderItemRemoveEvent $event) {
     ])->save();
   }
 
+  /**
+   * Creates a log when a quantity is updated.
+   *
+   * @param \Drupal\commerce_cart\Event\CartOrderItemUpdateEvent $event
+   *   The transition event.
+   */
+  public function onCartOrderItemUpdate(CartOrderItemUpdateEvent $event) {
+    $cart = $event->getCart();
+    $order_item = $event->getOrderItem();
+    $original_order_item = $event->getOriginalOrderItem();
+    $this->logStorage->generate($cart, 'cart_item_quantity_changed', [
+      'purchased_entity_label' => $order_item->getPurchasedEntity()->label(),
+      'original_quantity' => $original_order_item->getQuantity(),
+      'quantity' => $order_item->getQuantity(),
+    ])->save();
+  }
+
 }

modules/log/tests/src/Kernel/CartIntegrationTest.php

@@ -63,7 +63,6 @@ class CartIntegrationTest extends CommerceKernelTestBase {
     'commerce_log',
     'commerce_product',
     'commerce_order',
-    'commerce_test',
   ];
 
   /**
@@ -141,6 +140,24 @@ public function testRemovedFromCart() {
     $this->assertText("{$this->variation->label()} removed from the cart.");
   }
 
+  /**
+   * Tests that a log is generated when a quantity changed for an order item.
+   */
+  public function testQuantityChangedFromCart() {
+    $this->enableCommerceCart();
+    $cart = $this->cartProvider->createCart('default', $this->store, $this->createUser());
+    $order_item = $this->cartManager->addEntity($cart, $this->variation);
+    $order_item->setQuantity(2);
+    $this->cartManager->updateOrderItem($cart, $order_item);
+
+    $logs = $this->logStorage->loadByEntity($cart);
+    $log = end($logs);
+    $build = $this->logViewBuilder->view($log);
+    $this->render($build);
+
+    $this->assertText("Quantity of {$this->variation->label()} changed in the cart from 1.0 to 2.");
+  }
+
   /**
    * Enables commerce_cart for tests.
    *